start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250616 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Leg-biting fights reduce the number of sperm transferred by the loser and in draws in Zophobas atratus en-subtitle= kn-subtitle= en-abstract= kn-abstract=Intra-sexual selection has been observed across a wide range of species. Male-male combat can not only determine the winner and loser but also affect subsequent reproductive success. The effects of combat outcomes on reproduction are thought to depend on the reproductive ecology of the target species. However, to our knowledge, studies examining the impact of combat outcomes on sperm competition and fitness remain limited. In the giant mealworm (Zophobas atratus), male’s combat involves biting each other's hind legs. Females mated to the losers of leg-biting contests had significantly fewer eggs and fewer offspring than females mated to males that were not in a contest. Possible explanations for this fitness reduction include the inability of males to transfer sperm effectively due to the combat outcome or the inability of their sperm to fertilize eggs due to female cryptic sperm choice, and the mechanisms underlying this reduction remain unclear. Previous studies have observed distorted mating postures in losing males, leading us to hypothesize that leg-biting during combat might affect sperm transfer. To test this, we allowed uncontested males, winners, losers, and males with a draw outcome to mate with females and compared the number of sperm within the female’s spermatheca. Additionally, we examined the correlation between combat duration and sperm count. Results showed that losers and males with draw transferred fewer sperm than non-combat males. Moreover, the longer the combat duration, the fewer sperm males were able to transfer. These findings suggest that the reduction in sperm transferred was affected by both losing in combat and prolonged combat duration in leg-biting encounters. en-copyright= kn-copyright= en-aut-name=MatsuuraTeruhisa en-aut-sei=Matsuura en-aut-mei=Teruhisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil=Faculty of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Faculty of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= en-keyword=Male combat kn-keyword=Male combat en-keyword=Male-male competition kn-keyword=Male-male competition en-keyword=Sperm transfer kn-keyword=Sperm transfer en-keyword=Sperm biology kn-keyword=Sperm biology END start-ver=1.4 cd-journal=joma no-vol=25 cd-vols= no-issue=1 article-no= start-page=16 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250215 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Behavior, behavioral syndromes, and metabolism: the effects of artificial selection for death-feigning on metabolic rate en-subtitle= kn-subtitle= en-abstract= kn-abstract=Death-feigning, or thanatosis, is an anti-predator behavioral strategy in many animals. Because individuals remain immobile while feigning death, individuals with longer durations of death feigning often show lower locomotor activity. Thus, metabolic rate, which is closely related to locomotor activity, may also be related to the intensity of death feigning. If there is a genetic correlation between death feigning and metabolism, metabolic rate may respond to selection on death-feigning behavior. Here, we tested for a relationship between metabolic rate and death-feigning using replicated populations of the red flour beetle (Tribolium castaneum) subjected to artificial bidirectional selection on the duration of death-feigning behavior. The results indicated that metabolic rate did not differ between populations selected for increased or decreased death feigning, although locomotor activity was significantly different between these treatments; populations selected for reduced death-feigning durations tended to be more active. These results suggest that death-feigning behavior is not genetically correlated with metabolic rate in T. castaneum. en-copyright= kn-copyright= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HoskenDavid J. en-aut-sei=Hosken en-aut-mei=David J. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NodaTomohito en-aut-sei=Noda en-aut-mei=Tomohito kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SharmaManmohan D. en-aut-sei=Sharma en-aut-mei=Manmohan D. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Centre for Ecology and Conservation, Faculty of Environment, Science and Economy, University of Exeter kn-affil= affil-num=3 en-affil=Centre for Ecology and Conservation, Faculty of Environment, Science and Economy, University of Exeter kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=5 en-affil=Centre for Ecology and Conservation, Faculty of Environment, Science and Economy, University of Exeter kn-affil= en-keyword=anti-predator behavior kn-keyword=anti-predator behavior en-keyword=artificial selection kn-keyword=artificial selection en-keyword=death-feigning kn-keyword=death-feigning en-keyword=metabolic rate kn-keyword=metabolic rate en-keyword=personality kn-keyword=personality en-keyword=Tribolium kn-keyword=Tribolium END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250209 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effects of caffeine on the longevity and locomotion activity of the common green bottle fly, Lucilia sericata (Diptera: Calliphoridae) en-subtitle= kn-subtitle= en-abstract= kn-abstract=The common green bottle fly, Lucilia sericata (Meigen) (Diptera: Calliphoridae), is a promising and useful managed pollinator for greenhouse agricultural crops. The fly can pollinate at lower and higher temperatures than European honeybee. However, management of the longevity of pollinators is important for growers using greenhouses. Previous studies using other insects showed that caffeine affects insect longevity and behaviors. For instance, European honeybee live longer and have increased memory after caffeine consumption. How caffeine affects the longevity and behavior of pollinators is worth investigating because it can affect pollinator’s behavior, extend longevity, or be an insecticide against pollinators. In the present study, therefore, the longevity and locomotion of L. sericata were investigated when they were given different caffeine concentrations. First, the longevity of L. sericata with five different caffeine concentrations was compared to the control. The results showed that higher concentrations of caffeine (2%, 1%, and 0.5%) significantly decreased the life span compared to lower concentrations (0.05% and 0.01%). Second, the locomotion activities of L. sericata were examined at those two caffeine concentrations with treated and control male and female flies utilizing a Drosophila Activity Monitor (DAM). Treatment with 0.05% caffeine dramatically reduced locomotion, but treatment of 0.01% caffeine did not. We also compared lipid concentrations of flies: flies treated with 0.05% caffeine had a lower lipid concentration compared to flies treated with 0% and 0.01% caffeine. These results indicate that caffeine had negative effects on the longevity and locomotion activities of the pollinator L. sericata in laboratory conditions. en-copyright= kn-copyright= en-aut-name=NaingShine Shane en-aut-sei=Naing en-aut-mei=Shine Shane kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FujiokaHaruna en-aut-sei=Fujioka en-aut-mei=Haruna kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MatsuuraTeruhisa en-aut-sei=Matsuura en-aut-mei=Teruhisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= en-keyword=Caffeine kn-keyword=Caffeine en-keyword=Life span kn-keyword=Life span en-keyword=Locomotor activity kn-keyword=Locomotor activity en-keyword=Pollinator kn-keyword=Pollinator END start-ver=1.4 cd-journal=joma no-vol=37 cd-vols= no-issue=2 article-no= start-page=152 end-page=158 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240801 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Death Feigning in Larvae of Scorpionflies (Mecoptera: Panorpidae): Frequency and Postural Changes Based on Larval Instars en-subtitle= kn-subtitle= en-abstract= kn-abstract=Death feigning is thought to have evolved primarily as a predator avoidance behavior, and has been reported in 10 of the 31 orders of insects. However, there have been no reports of death-feigning behavior in Mecoptera species. We found that larvae of two scorpionfly species, Panorpa japonica and P. pryeri, showed death feigning in response to external stimuli by brush poking stimulation. First, we examined the frequencies of death-feigning postures. The two species showed two different postures of death feigning, “straight” and “ball.” Most of the 1st instar larvae of P. japonica and P. pryeri adopted the straight death-feigning posture. Next, we examined duration of death feigning. As the larval instar progressed, the death-feigning posture shifted from straight to ball in both Panorpa species. In P. japonica, the longest durations of death feigning were found in the 2nd to 3rd instars, while the longest duration of death feigning was found in the late 4th instar in P. pryeri larvae. en-copyright= kn-copyright= en-aut-name=IshiharaRyo en-aut-sei=Ishihara en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= en-keyword=Anti-predator behavior kn-keyword=Anti-predator behavior en-keyword=freezing kn-keyword=freezing en-keyword=larvae kn-keyword=larvae en-keyword=thanatosis kn-keyword=thanatosis en-keyword=tonic immobility kn-keyword=tonic immobility END start-ver=1.4 cd-journal=joma no-vol=42 cd-vols= no-issue=3 article-no= start-page=177 end-page=185 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240718 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Reduced fitness in losers of leg-biting male combat compared to uncontested males in Zophobas atratus en-subtitle= kn-subtitle= en-abstract= kn-abstract=Sexual dimorphism and male combat are observed in many species. Often, the outcome of male combat affects the outcome of subsequent combats, mating success, number of sperm, and fitness of the male’s offspring. Also, the quantity and quality of sperm may be regulated by winning or losing, depending on species ecology and mating system. However, very few studies have experimentally examined the influence of fight outcomes on male offspring fitness. We studied male combat in the giant mealworm (Zophobas atratus) in which males bite each other’s hind legs. We hypothesized that subsequent fitness could differ between winners and losers in the escalated male combat of this species. We measured several fitness traits including the number of eggs laid by mated females, and the number of hatches sired by uncontested males, winners, and losers in escalated and non-escalated combat, and compared the fitness of each winner and loser to that of an uncontested male. We also measured mating duration. The numbers of eggs and the percentages of hatched eggs of losers in the escalated combat were significantly reduced compared to that of the uncontested males. This reduction may be due to injuries from escalated leg- biting fights and a result of the sperm amount of the uncontested males being greater than that of the loser males. en-copyright= kn-copyright= en-aut-name=MatsuuraTeruhisa en-aut-sei=Matsuura en-aut-mei=Teruhisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= en-keyword=Beetle kn-keyword=Beetle en-keyword=Offspring fitness kn-keyword=Offspring fitness en-keyword=Male combat kn-keyword=Male combat en-keyword=Hind leg kn-keyword=Hind leg en-keyword=Weapon kn-keyword=Weapon END start-ver=1.4 cd-journal=joma no-vol=59 cd-vols= no-issue=3 article-no= start-page=267 end-page=271 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240508 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Body-size-dependent predation by some jumping spider species (Araneae: Salticidae) on Tribolium castaneum (Coletptera: Tenebrionidae) en-subtitle= kn-subtitle= en-abstract= kn-abstract=We examined the predation of two synanthropic jumping spiders, Hasarius adansoni (Araneae: Salticidae) and Plexippus paykulli (Araneae: Salticidae), on Tribolium castaneum (Herbst) (Coletptera: Tenebrionidae), a grain storage pest, that is sometimes found with these species to determine whether the predatory success of synanthropic and grassland jumping spiders on T. castaneum differs. We examined the predation of two synanthropic and three grassland jumping spiders on T. castaneum adults and larvae. We found that the two synanthropic species preyed on T. castaneum adults and larvae, while the three grassland species never attacked T. castaneum adults. The success or failure of predation on T. castaneum adults also depended on the body size of the jumping spiders. en-copyright= kn-copyright= en-aut-name=HayashiToma en-aut-sei=Hayashi en-aut-mei=Toma kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=77 cd-vols= no-issue=7 article-no= start-page=85 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=202307 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Latitudinal cline in reproductive traits in the red flour beetle Tribolium castaneum en-subtitle= kn-subtitle= en-abstract= kn-abstract=Several previous studies have reported geographic variation and/or latitudinal clines of morphological sexual characteristics, but there are few studies that consider reproductive traits that are not morphological. Here, we measured the proportion of females fertilized by males, frequency of reproductive failure in males, and number of female copulations of the red flour beetle Tribolium castaneum collected from fields in Japan to investigate the relationship between reproductive traits and latitude. Our results show substantial differences in the reproductive traits of both sexes among field populations. We identified latitudinal clines for reproductive traits in males, but not females. Moreover, female, but not male, reproductive traits were correlated with body size. Our study suggests that selection for male reproductive traits varies with latitude in T. castaneum. en-copyright= kn-copyright= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=WakabayashiKyosuke en-aut-sei=Wakabayashi en-aut-mei=Kyosuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KawakamiRenya en-aut-sei=Kawakami en-aut-mei=Renya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Faculty of Agriculture, Kagawa University kn-affil= affil-num=4 en-affil=Graduate School of Environmental, Life Science and Technology, Okayama University kn-affil= en-keyword=Sexual selection kn-keyword=Sexual selection en-keyword=Sexual conflict kn-keyword=Sexual conflict en-keyword=Geographic variation kn-keyword=Geographic variation en-keyword=Tribolium castaneum kn-keyword=Tribolium castaneum END start-ver=1.4 cd-journal=joma no-vol=14 cd-vols= no-issue=1 article-no= start-page=67 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240102 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Transcriptomic comparison between populations selected for higher and lower mobility in the red flour beetle Tribolium castaneum en-subtitle= kn-subtitle= en-abstract= kn-abstract=Movement is an important behavior observed in a wide range of taxa. Previous studies have examined genes controlling movement using wing polymorphic insects and genes controlling wing size. However, few studies have investigated genes controlling movement activity rather than morphological traits. In the present study, we conducted RNA sequencing using populations with higher (WL) and lower (WS) mobility established by artificial selection in the red flour beetle Tribolium castaneum and compared gene expression levels between selected populations with two replicate lines. As a result, we found significant differences between the selected populations in 677 genes expressed in one replicate line and 1198 genes expressed in another replicate line, of which 311 genes were common to the two replicate lines. Furthermore, quantitative PCR focusing on 6 of these genes revealed that neuropeptide F receptor gene (NpF) was significantly more highly expressed in the WL population than in the WS population, which was common to the two replicate lines. We discuss differences in genes controlling movement between walking activity and wing polymorphism. en-copyright= kn-copyright= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OnumaTakafumi en-aut-sei=Onuma en-aut-mei=Takafumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KondoShinji en-aut-sei=Kondo en-aut-mei=Shinji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NoguchiHideki en-aut-sei=Noguchi en-aut-mei=Hideki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=UchiyamaHironobu en-aut-sei=Uchiyama en-aut-mei=Hironobu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=YajimaShunsuke en-aut-sei=Yajima en-aut-mei=Shunsuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=SasakiKen en-aut-sei=Sasaki en-aut-mei=Ken kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil=Graduate School of Environment, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Agriculture, Tamagawa University kn-affil= affil-num=3 en-affil=Center for Genome Informatics, Research Organization of Information and Systems, Joint Support-Center for Data Science Research kn-affil= affil-num=4 en-affil=Center for Genome Informatics, Research Organization of Information and Systems, Joint Support-Center for Data Science Research kn-affil= affil-num=5 en-affil=NODAI Genome Research Center, Tokyo University of Agriculture kn-affil= affil-num=6 en-affil=NODAI Genome Research Center, Tokyo University of Agriculture kn-affil= affil-num=7 en-affil=Graduate School of Agriculture, Tamagawa University kn-affil= affil-num=8 en-affil=Graduate School of Environment, Life, Natural Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=78 cd-vols= no-issue=3 article-no= start-page=34 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240224 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Experimental quantification of genetic and ontogenetic effects on fighting behavior in the broad-horned flour beetle en-subtitle= kn-subtitle= en-abstract= kn-abstract=Most animal behaviors show large within- and among-individual variation, and this includes competitive male behaviors. With male fighting for example, aggressiveness often correlates with dominance, and contest duration varies with age. However, few studies have directly quantified how mean aggressiveness and contest duration, the variation among individuals in both traits, and the relationship among them, vary with age. Here we address these gaps and examine the effect of male age and genotype on two key aspects of male fighting behavior - aggressiveness (here measured as latency to fight) and contest duration - and the relationship between them. We do this using isogenic lines of the broad-horned flour beetle Gnatocerus cornutus. We observed fighting behavior of paired males of similar body size and age. Using uni- and multivariate mixed models, we show that although there was a significant difference between younger and older males in contest duration, mean aggressiveness was not affected by male age. However, the variation in aggression and fight duration varied with age, being greater in younger and older males respectively. Additionally, although there was a positive correlation between aggressiveness and contest duration in younger males, this relationship was not found in older males. Finally, the only significant genetic effect was for aggression in younger males. Our study shows that age differentially shapes key components of male fighting behavior as well as the relationship among them, highlighting the dynamic nature and context-dependence of fighting. en-copyright= kn-copyright= en-aut-name=NishitaniToshiki en-aut-sei=Nishitani en-aut-mei=Toshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=PostmaErik en-aut-sei=Postma en-aut-mei=Erik kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SharmaManmohan Dev en-aut-sei=Sharma en-aut-mei=Manmohan Dev kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HoskenDavid J en-aut-sei=Hosken en-aut-mei=David J kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural and Technology, Okayama University kn-affil= affil-num=3 en-affil=Centre for Ecology & Conservation, University of Exeter, Penryn Campus kn-affil= affil-num=4 en-affil=Centre for Ecology & Conservation, University of Exeter, Penryn Campus kn-affil= affil-num=5 en-affil=Centre for Ecology & Conservation, University of Exeter, Penryn Campus kn-affil= affil-num=6 en-affil=Graduate School of Environmental, Life, Natural and Technology, Okayama University kn-affil= en-keyword=Male-male contest kn-keyword=Male-male contest en-keyword=Contest kn-keyword=Contest en-keyword=Aggressiveness kn-keyword=Aggressiveness en-keyword=Aging kn-keyword=Aging en-keyword=Genetics kn-keyword=Genetics en-keyword=Beetle kn-keyword=Beetle END start-ver=1.4 cd-journal=joma no-vol=59 cd-vols= no-issue=2 article-no= start-page=117 end-page=126 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240221 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Spatio-temporal distribution of adults and eggs of the West Indian sweetpotato weevil Euscepes postfasciatus (Coleoptera: Curculionidae) on sweet potato stems en-subtitle= kn-subtitle= en-abstract= kn-abstract=The West Indian sweetpotato weevil, Euscepes postfasciatus, a serious pest of sweet potatoes, is being eradicated by sterile insect technique (SIT) in the south-western islands of Japan. Information on the diurnal movement of the target pests on host plants and where mating and egg-laying behavior occurs on the host is important for the application of SIT, which eradicates the target pest through mating of released sterile males and wild females. However, little such information is available on this species. In this study, male and female adults were released on host plants to examine the diurnal distribution on seedlings according to sex, as well as the sites where mounting behavior and egg laying occurs. The results showed that females left the host plant more frequently at night, whereas males were more likely to remain on the host plant at night. Both males and females stayed on the nodes of the host plant during the daytime. Mounting behavior also tended to occur more often at nodes. Furthermore, compared to unmated females, mated females stayed at the vertical top of the seedlings. However, it was found that eggs were often laid close to the roots rather than at the top of the vertical stems, even when the seedlings were placed upside down. The results of previous studies and this study will be discussed from the perspective of the application of SIT against E. postfasciatus. en-copyright= kn-copyright= en-aut-name=UrasakiKimiko en-aut-sei=Urasaki en-aut-mei=Kimiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Okinawa Prefectural Plant Protection Center kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= en-keyword=Diurnal pattern kn-keyword=Diurnal pattern en-keyword=Eggs kn-keyword=Eggs en-keyword=Mating system kn-keyword=Mating system en-keyword=Mounting kn-keyword=Mounting en-keyword=Weevil kn-keyword=Weevil END start-ver=1.4 cd-journal=joma no-vol=42 cd-vols= no-issue=1 article-no= start-page=71 end-page=75 dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230913 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Aggregation pheromone interrupts death feigning in the red flour beetle Tribolium castaneum en-subtitle= kn-subtitle= en-abstract= kn-abstract=Death feigning is a behavior in which a prey is rendered motionless due to stimulation or threat by a predator. This anti-predator defense mechanism has been observed across a wide range of animal taxa and is considered adaptive. However, long durations of death feigning can decrease opportunities for feeding and reproduction, and therefore is a fitness cost as compared to environments without predators. Because death feigning is thought to be affected by the balance between survival and other fitness costs, selection pressure may drive individuals who are capable of plastic changes in the intensity of death feigning. Pheromones, which are important semiochemicals that affect foraging and reproductive success, may be one of the factors influencing the intensity of death-feigning behavior. In this study, we investigated the effect of an aggregation pheromone on the death-feigning behavior of the red flour beetle Tribolium castaneum. We found that beetles exposed to the pheromone showed a significantly shorter duration of death feigning than beetles that were not exposed to the pheromone. Therefore, our results suggest that an aggregation pheromone can plasticly alter the death-feigning behavior in T. castaneum. en-copyright= kn-copyright= en-aut-name=IshikawaMotoya en-aut-sei=Ishikawa en-aut-mei=Motoya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= en-keyword=Anti-predator strategies kn-keyword=Anti-predator strategies en-keyword=Death feigning kn-keyword=Death feigning en-keyword=Aggregation pheromone kn-keyword=Aggregation pheromone en-keyword=Sexual selection kn-keyword=Sexual selection en-keyword=Tribolium castaneum kn-keyword=Tribolium castaneum END start-ver=1.4 cd-journal=joma no-vol=58 cd-vols= no-issue=3 article-no= start-page=257 end-page=263 dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230607 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Sex and strain-specific spectral attraction of Tribolium castaneum (Coleoptera: Tenebrionidae): behavioral studies en-subtitle= kn-subtitle= en-abstract= kn-abstract=We examined the attraction of adults to six LEDs in the red flour beetles, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), which is widespread as a stored grain insect. In the experiment, bluish green and green were more attractive than the two UVs, blue, and red LEDs only in females. On the other hand, no difference was found in attraction among the six LEDs in males. Next, we investigated the relationship between light intensity and attractiveness. No sexual difference in attractiveness in different light intensities was found, but the strongest light intensity was more attractive than other light intensities. Finally, we investigated the relationship between light attraction and strains artificially selected for the duration of death feigning. Short-strain beetles were more attracted to UV lights than long-strain beetles. en-copyright= kn-copyright= en-aut-name=SoneSota en-aut-sei=Sone en-aut-mei=Sota kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= en-keyword=Behavior kn-keyword=Behavior en-keyword=LED kn-keyword=LED en-keyword=Light response kn-keyword=Light response en-keyword=Photoresponse kn-keyword=Photoresponse en-keyword=Red flour beetle kn-keyword=Red flour beetle en-keyword=Stored insects kn-keyword=Stored insects END start-ver=1.4 cd-journal=joma no-vol=25 cd-vols= no-issue=4 article-no= start-page=101999 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=202212 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Longevity of Lucilia sericata (Meigen, 1826) used as pollinator en-subtitle= kn-subtitle= en-abstract= kn-abstract=Pollinators play an important role in the production of many agricultural products. Honeybees, Apis mellifera L., are leading pollinators, but the number of honeybees in the world is declining. Finding alternatives is beginning to be important. In the present study, we compared the longevity of Lucilia sericata (Meigen, 1826), which is used as a pollinator, in cages in the laboratory and in a vinyl greenhouse under controlled feeding conditions. First, we showed that the longevity of the flies was significantly extended (c.a. 40 days) in the laboratory when water and sugar were supplied compared to the cases without sugar and/or water. Second, we found that the average longevity was 20 days with water and sugar in cages kept in a vinyl greenhouse during the summer. Finally, we released marked flies into a vinyl greenhouse where strawberries were cultivated without feeding water or sugar in the spring. As a result, fewer than 10% of the flies survived 10 days after release. Based on the result, we discuss the use of this species as a pollinator in the context of its survival rate. en-copyright= kn-copyright= en-aut-name=ShimomaeKoichi en-aut-sei=Shimomae en-aut-mei=Koichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SatoTakuya en-aut-sei=Sato en-aut-mei=Takuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YoshidaYuichi en-aut-sei=Yoshida en-aut-mei=Yuichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NaingShine Shane en-aut-sei=Naing en-aut-mei=Shine Shane kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Japan Maggot Company, Co. Ltd. kn-affil= affil-num=3 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=Diptera kn-keyword=Diptera en-keyword=Lifespan kn-keyword=Lifespan en-keyword=Pollination kn-keyword=Pollination en-keyword=Quality control kn-keyword=Quality control END start-ver=1.4 cd-journal=joma no-vol=128 cd-vols= no-issue= article-no= start-page=453 end-page=460 dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220329 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Artificial selections for death-feigning behavior in beetles show correlated responses in amplitude of circadian rhythms, but the period of the rhythm does not en-subtitle= kn-subtitle= en-abstract= kn-abstract=One of the most important survival strategies of organisms is to avoid predators. Studying one of such strategies, namely, death-feigning behavior, has recently become more common. The success or failure of this antipredator strategy will be affected by the circadian rhythms of both prey and predator because death feigning sometimes has a diurnal rhythm. However, few studies have analyzed the effects of differences in circadian rhythms on predator-avoidance behavior at the genetic level. Recently, the relationship between genes relating to circadian rhythm and death-feigning behavior, an antipredator behavior, has been established at the molecular level. Therefore, in this study, we compared three circadian rhythm-related traits, the free-running period of rhythms, amplitude of circadian rhythms, and total activity of strains of three Tribolium species that were artificially selected for the death-feigning duration: short (S-strains) and long (L-strains) durations. As a result, the amplitude of circadian rhythms and total activity were significantly different between S- and L-strains, but there was no difference in the free-running periods of the rhythm between the strains in T. castaneum, T. confusum, and T. freemani. Although the relationship between death-feigning behavior and activity has been reported for all three species, a genetic relationship between the duration of death feigning and the amplitude of circadian rhythms has been newly found in the present study. It is important to investigate the relationship between antipredator strategies and circadian rhythms at the molecular level in the future. en-copyright= kn-copyright= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=S. AbeMasato en-aut-sei=S. Abe en-aut-mei=Masato kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YoshiiTaishi en-aut-sei=Yoshii en-aut-mei=Taishi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Center for Advanced Intelligence Project, RIKEN kn-affil= affil-num=3 en-affil=Laboratory of entomology, Faculty of Agriculture kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=biological clock kn-keyword=biological clock en-keyword=coleoptera kn-keyword=coleoptera en-keyword=death feigning kn-keyword=death feigning en-keyword=thanatosis kn-keyword=thanatosis en-keyword=tonic immobility kn-keyword=tonic immobility END start-ver=1.4 cd-journal=joma no-vol=12 cd-vols= no-issue=2 article-no= start-page=e8533 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220207 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Freezing or death feigning? Beetles selected for long death feigning showed different tactics against different predators en-subtitle= kn-subtitle= en-abstract= kn-abstract=Prey evolve antipredator strategies against multiple enemies in nature. We examined how a prey species adopts different predation avoidance tactics against pursuit or sit-and-wait predators. As prey, we used three strains of Tribolium beetles artificially selected for short (short strain) or long (long strain) duration of death feigning, and a stock culture (base population). Death feigning is known to be effective for evading a jumping spider in the case of the long strains, while the present study showed that the long-strain beetles used freezing against a sit-and-wait type predator, Amphibolus venator, in this study. The short- strain beetles were more easily oriented toward predators. The time to predation was also shorter in the short strains compared to the long strains. The results showed that, as prey, the short strains displayed the same behavior, escaping, against both types of predators. Traditionally, death feigning has been thought to be the last resort in a series of antipredator avoidance behaviors. However, our results showed that freezing and death feigning were not parts of a series of behaviors, but independent strategies against different predators, at least for long-strain beetles. We also examined the relationship between a predator's starvation level and its predatory behavior. In addition, the orientation behavior toward and predation rate on the prey were observed to determine how often the predatory insect attacked the beetles. en-copyright= kn-copyright= en-aut-name=AsakuraMasaya en-aut-sei=Asakura en-aut-mei=Masaya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=IshiharaRyo en-aut-sei=Ishihara en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Agriculture, Kagawa University kn-affil= affil-num=3 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=animal hypnosis kn-keyword=animal hypnosis en-keyword=death feigning kn-keyword=death feigning en-keyword=freezing kn-keyword=freezing en-keyword=predation kn-keyword=predation en-keyword=thanatosis kn-keyword=thanatosis en-keyword=tonic immobility kn-keyword=tonic immobility END start-ver=1.4 cd-journal=joma no-vol=11 cd-vols= no-issue=1 article-no= start-page=21816 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20211108 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Genomic characterization between strains selected for death-feigning duration for avoiding attack of a beetle en-subtitle= kn-subtitle= en-abstract= kn-abstract=Predator avoidance is an important behavior that affects the degree of adaptation of organisms. We compared the DNA variation of one of the predator-avoidance behaviors, the recently extensively studied "death-feigning behavior", between the long strain bred for feigning death for a long time and the short strain bred for feigning death for a short time. To clarify how the difference in DNA sequences between the long and short strains corresponds to the physiological characteristics of the death-feigning duration at the transcriptome level, we performed comprehensive and comparative analyses of gene variants in Tribolium castaneum strains using DNA-resequencing. The duration of death feigning involves many gene pathways, including caffeine metabolism, tyrosine metabolism, tryptophan metabolism, metabolism of xenobiotics by cytochrome P450, longevity regulating pathways, and circadian rhythm. Artificial selection based on the duration of death feigning results in the preservation of variants of genes in these pathways in the long strain. This study suggests that many metabolic pathways and related genes may be involved in the decision-making process of anti-predator animal behavior by forming a network in addition to the tyrosine metabolic system, including dopamine, revealed in previous studies. en-copyright= kn-copyright= en-aut-name=TanakaKeisuke en-aut-sei=Tanaka en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SasakiKen en-aut-sei=Sasaki en-aut-mei=Ken kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YajimaShunsuke en-aut-sei=Yajima en-aut-mei=Shunsuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=NODAI Genome Research Center, Tokyo University of Agriculture kn-affil= affil-num=2 en-affil=Graduate School of Agriculture, Tamagawa University kn-affil= affil-num=3 en-affil=Graduate School of Agriculture, Kagawa University kn-affil= affil-num=4 en-affil=NODAI Genome Research Center, Tokyo University of Agriculture kn-affil= affil-num=5 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=169 cd-vols= no-issue= article-no= start-page=959 end-page=965 dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=202175 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Selection for age at reproduction changes pre‐mating period and mating frequency in Zeugodacus cucurbitae : impacts on insect quality control en-subtitle= kn-subtitle= en-abstract= kn-abstract=In the mass-rearing of insects for sterile insect technique (SIT), it is important to maintain the quality of mass-reared males so that they can compete with wild males in mating with wild females. Mass-reared insects sometimes have shorter pre-mating periods and higher mating frequencies than their wild conspecifics. Indeed, this was the case for mass-reared individuals of the melon fly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae), used in the SIT program to eradicate the melon fly on the Southwest Islands of Japan. Therefore, I hypothesized that divergent artificial selection for age at reproduction altered these traits in the melon fly as well. To examine the effects of eggs produced by younger parents on each generation, six artificially selected lines were established, for which eggs were collected from young (Y lines) and old (O lines) females. Then, the pre-mating periods and mating frequencies in males and females of the selected lines were compared. The results show a decreased pre-mating period and an increased mating frequency in younger lines compared to older lines, which was driven by males rather than females. These traits ensure efficient offspring production in mass-rearing, and are likely advantageous to the success of SIT programs. The impact of artificially selecting for these traits, especially in males, on insect quality and the efficiency of SIT is discussed. en-copyright= kn-copyright= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= affil-num=1 en-affil=Laboratory of Evolutionary Ecology, Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=Zeugodacus cucurbitae kn-keyword=Zeugodacus cucurbitae en-keyword=mass-rearing kn-keyword=mass-rearing en-keyword=mating kn-keyword=mating en-keyword=melon fly kn-keyword=melon fly en-keyword=quality 16 control kn-keyword=quality 16 control en-keyword=sterile insect technique kn-keyword=sterile insect technique en-keyword=SIT kn-keyword=SIT en-keyword=Diptera kn-keyword=Diptera en-keyword=Tephritidae kn-keyword=Tephritidae en-keyword=correlated responses kn-keyword=correlated responses END start-ver=1.4 cd-journal=joma no-vol=24 cd-vols= no-issue=1 article-no= start-page=376 end-page=382 dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210201 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Swarming and mating behavior in Ephemera orientalis Mclachlan, 1875 (Ephemeroptera: Ephemeridae) with morphological analyses en-subtitle= kn-subtitle= en-abstract= kn-abstract=Swarming and mating behaviors of a mayfly species, Ephemera orientalis Mclachlan, 1875 were observed in 2015, 2016, and 2018 at a river bank of the Asahi River, Japan. Males started to make swarms between late April and middle May in 2016 and 2018. The numbers of mated pairs in a swarm correlated with the numbers of flying males in a swarm in 2016 and 2018. Swarms were formed during a limited period at dusk most probably because that interval is free from natural enemies. Males competed with each other to copulate with females in swarms. We clarified the function of the forelegs of males, which are significantly longer than those of females. Males used their forelegs to hold up a female from below. Besides forelegs, males have longer tails than females. We will discuss why sexual differences are found in these traits. Our results represent the first observation of swarm mating behavior in E. orientalis. en-copyright= kn-copyright= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SugeTaichi en-aut-sei=Suge en-aut-mei=Taichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SuzakiShunsuke en-aut-sei=Suzaki en-aut-mei=Shunsuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=TanabeShintaro en-aut-sei=Tanabe en-aut-mei=Shintaro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=IshiharaRyo en-aut-sei=Ishihara en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=Aquatic insect kn-keyword=Aquatic insect en-keyword=Emergence kn-keyword=Emergence en-keyword=Copulation kn-keyword=Copulation en-keyword=Foreleg kn-keyword=Foreleg en-keyword=Mayfly kn-keyword=Mayfly en-keyword=Swarm kn-keyword=Swarm END start-ver=1.4 cd-journal=joma no-vol=158 cd-vols= no-issue=2 article-no= start-page=123 end-page=133 dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210111 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Age-dependent walking and feeding of the assassin bug Amphibolus venator en-subtitle= kn-subtitle= en-abstract= kn-abstract=Animal behaviours often dependent on age. In many insect species, walking shows an age-dependent decline, and food intake may also be dependent on age. However, few studies have investigated the relationship between age and walking or food intake. In the present study, we compared walking traits and food intake among individuals of different ages in the assassin bug Amphibolus venator (Hemiptera, Reduviidae). The present results showed an age-dependent decline in walking, similar to findings in many animal species. On the other hand, food intake showed a positive correlation with age. Therefore, the decline in walking did not lead to a decline in feeding. The positive relationship between food intake and age may be related to the type of predation, sit-and-wait, used by A. venator via alterations in investment in reproductive traits with age. en-copyright= kn-copyright= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=IwayaMana en-aut-sei=Iwaya en-aut-mei=Mana kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NagayaNaohisa en-aut-sei=Nagaya en-aut-mei=Naohisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=FujisawaRyusuke en-aut-sei=Fujisawa en-aut-mei=Ryusuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Faculty of Agriculture, Okayama University kn-affil= affil-num=3 en-affil=Kyoto Sangyo University kn-affil= affil-num=4 en-affil=Kyushu Institute of Technology kn-affil= affil-num=5 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=age-dependent kn-keyword=age-dependent en-keyword=walking kn-keyword=walking en-keyword=food intake kn-keyword=food intake en-keyword=sit-and-wait predator kn-keyword=sit-and-wait predator en-keyword=Amphibolus venator kn-keyword=Amphibolus venator END start-ver=1.4 cd-journal=joma no-vol=16 cd-vols= no-issue=1 article-no= start-page=e0245115 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20210114 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Amplitude of circadian rhythms becomes weaken in the north, but there is no cline in the period of rhythm in a beetle en-subtitle= kn-subtitle= en-abstract= kn-abstract=Many species show rhythmicity in activity, from the timing of flowering in plants to that of foraging behavior in animals. The free-running periods and amplitude (sometimes called strength or power) of circadian rhythms are often used as indicators of biological clocks. Many reports have shown that these traits are highly geographically variable, and interestingly, they often show latitudinal or longitudinal clines. In many cases, the higher the latitude is, the longer the free-running circadian period (i.e., period of rhythm) in insects and plants. However, reports of positive correlations between latitude or longitude and circadian rhythm traits, including free-running periods, the power of the rhythm and locomotor activity, are limited to certain taxonomic groups. Therefore, we collected a cosmopolitan stored-product pest species, the red flour beetle Tribolium castaneum, in various parts of Japan and examined its rhythm traits, including the power and period of the rhythm, which were calculated from locomotor activity. The analysis revealed that the power was significantly lower for beetles collected in northern areas than southern areas in Japan. However, it is worth noting that the period of circadian rhythm did not show any clines; specifically, it did not vary among the sampling sites, despite the very large sample size (n = 1585). We discuss why these cline trends were observed in T. castaneum. en-copyright= kn-copyright= en-aut-name=AbeMasato S. en-aut-sei=Abe en-aut-mei=Masato S. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YoshiiTaishi en-aut-sei=Yoshii en-aut-mei=Taishi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Center for Advanced Intelligence Project, RIKEN kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil= Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=127 cd-vols= no-issue=1 article-no= start-page=45 end-page=49 dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=202101 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effects of caffeine on mating behavior and sperm precedence in Tribolium castaneum en-subtitle= kn-subtitle= en-abstract= kn-abstract=Biogenic amines such as dopamine are physiologically neuroactive substances that affect behavioral and physiological traits in invertebrates, and it has long been known that these substances affect mating behavior in insects. Caffeine is a dopamine activator and thus enhances dopamine receptor activity. However, the effects of caffeine intake on insect mating behavior have been largely unexplored. Therefore, we examined the effect of caffeine on mating behavior in the red flour beetle Tribolium castaneum. Caffeine, which activates dopamine, affected the mating behavior of T. castaneum males. Males who orally ingested caffeine courted faster than males who did not, resulting in faster mounting of females and less time to a male's external aedeagus protrusion. However, the present results showed no difference in sperm precedence measured as a P2 value between males fed caffeine and males not fed caffeine. We discuss the effects of caffeine on insect mating and the possibility that caffeine consumption may cause males to mate with more females in the laboratory. en-copyright= kn-copyright= en-aut-name=JiYuhao en-aut-sei=Ji en-aut-mei=Yuhao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=RyujiYuki en-aut-sei=Ryuji en-aut-mei=Yuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Faculty of Agriculture, Kagawa University kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=mating latency kn-keyword=mating latency en-keyword=mounting behavior kn-keyword=mounting behavior en-keyword=number of mating kn-keyword=number of mating en-keyword=red flour beetle kn-keyword=red flour beetle en-keyword=reproductive success kn-keyword=reproductive success en-keyword=sperm competition kn-keyword=sperm competition END start-ver=1.4 cd-journal=joma no-vol=39 cd-vols= no-issue= article-no= start-page=107 end-page=113 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20201020 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Arousal from death feigning by vibrational stimuli: comparison of Tribolium species en-subtitle= kn-subtitle= en-abstract= kn-abstract=Death feigning (or tonic immobility) is an effective antipredator strategy. However, prolonged immobility on the ground increases the risk of being parasitized or eaten by predators, and thus, insects must rouse themselves when appropriate stimulation is provided. Very few studies on the effect of stimulus intensity on arousal from death feigning have been conducted. A previous study using Tribolium castaneum showed an existing threshold for the intensity of the stimulus that causes arousal from death feigning. Whether there are differences between species in the threshold for arousal is an interesting question. In the present study, we, therefore, compared the effect of stimulus strength on arousal from death feigning in two closely related species, namely, T. confusum and T. freemani, which are established strains that have been artificially selected for longer duration of death feigning. Also, part of the study was to determine whether there was a positive association between intensity of stimulus needed to rouse and the duration of death feigning. We discuss why there is a difference in the strength of the stimulus needed for arousal from death feigning among Tribolium species, for which we included the data for T. castaneum from a previous study. en-copyright= kn-copyright= en-aut-name=IshiharaRyo en-aut-sei=Ishihara en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=JonesJordan Elouise en-aut-sei=Jones en-aut-mei=Jordan Elouise kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YuhaoJi en-aut-sei=Yuhao en-aut-mei=Ji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=FujisawaRyusuke en-aut-sei=Fujisawa en-aut-mei=Ryusuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NagayaNaohisa en-aut-sei=Nagaya en-aut-mei=Naohisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Department of Evolutionary Ecology, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Evolutionary Ecology, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Department of Evolution, Ecology and Behaviour, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool kn-affil= affil-num=4 en-affil=Department of Evolutionary Ecology, Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=5 en-affil=School of Computer Science and Systems Engineering, Kyushu Institute of Technology kn-affil= affil-num=6 en-affil=Faculty of Information Science and Engineering, Kyoto Sangyo University kn-affil= affil-num=7 en-affil=Department of Evolutionary Ecology, Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=Beetle kn-keyword=Beetle en-keyword=Death feigning kn-keyword=Death feigning en-keyword=Selection experiment kn-keyword=Selection experiment en-keyword=Species comparison kn-keyword=Species comparison en-keyword=Thanatosis kn-keyword=Thanatosis en-keyword=Tonic immobility kn-keyword=Tonic immobility en-keyword=Tribolium kn-keyword=Tribolium END start-ver=1.4 cd-journal=joma no-vol=130 cd-vols= no-issue=1 article-no= start-page=34 end-page=40 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200507 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Genetic variation and phenotypic plasticity in circadian rhythms in an armed beetle, Gnatocerus cornutus (Tenebrionidae) en-subtitle= kn-subtitle= en-abstract= kn-abstract=Circadian rhythms, their free-running periods and the power of the rhythms are often used as indicators of biological clocks, and there is evidence that the free-running periods of circadian rhythms are not affected by environmental factors, such as temperature. However, there are few studies of environmental effects on the power of the rhythms, and it is not clear whether temperature compensation is universal. Additionally, genetic variation and phenotypic plasticity in biological clocks are important for understanding the evolution of biological rhythms, but genetic and plastic effects are rarely investigated. Here, we used 18 isofemale lines (genotypes) of Gnatocerus cornutus to assess rhythms of locomotor activity, while also testing for temperature effects. We found that total activity and the power of the circadian rhythm were affected by interactions between sex and genotype or between sex, genotype and temperature. The males tended to be more active and showed greater increases in activity, but this effect varied across both genotypes and temperatures. The period of activity varied only by genotype and was thus independent of temperature. The complicated genotype?sex?environment interactions we recorded stress the importance of investigating circadian activity in more integrated ways. en-copyright= kn-copyright= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=AbeMasato S en-aut-sei=Abe en-aut-mei=Masato S kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SharmaManmohan D en-aut-sei=Sharma en-aut-mei=Manmohan D kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=HoskenDavid J en-aut-sei=Hosken en-aut-mei=David J kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YoshiiTaishi en-aut-sei=Yoshii en-aut-mei=Taishi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Center for Advanced Intelligence Project, RIKEN kn-affil= affil-num=3 en-affil=Centre for Ecology and Conservation, School of Biosciences, University of Exeter kn-affil= affil-num=4 en-affil=Centre for Ecology and Conservation, School of Biosciences, University of Exeter kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=circadian rhythm kn-keyword=circadian rhythm en-keyword=Gnatocerus cornutus kn-keyword=Gnatocerus cornutus en-keyword=isofemale line kn-keyword=isofemale line en-keyword=power of circadian rhythm kn-keyword=power of circadian rhythm END start-ver=1.4 cd-journal=joma no-vol=33 cd-vols= no-issue=8 article-no= start-page=1120 end-page=1128 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200519 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Death feigning as an adaptive anti‐predator behaviour: Further evidence for its evolution from artificial selection and natural populations en-subtitle= kn-subtitle= en-abstract= kn-abstract=Death feigning is considered to be an adaptive antipredator behaviour. Previous studies on Tribolium castaneum have shown that prey which death feign have a fitness advantage over those that do not when using a jumping spider as the predator. Whether these effects are repeatable across species or whether they can be seen in nature is, however, unknown. Therefore, the present study involved two experiments: (a) divergent artificial selection for the duration of death feigning using a related species T. freemani as prey and a predatory bug as predator, demonstrating that previous results are repeatable across both prey and predator species, and (b) comparison of the death‐feigning duration of T. castaneum populations collected from field sites with and without predatory bugs. In the first experiment, T. freemani adults from established selection regimes with longer durations of death feigning had higher survival rates and longer latency to being preyed on when they were placed with predatory bugs than the adults from regimes selected for shorter durations of death feigning. As a result, the adaptive significance of death‐feigning behaviour was demonstrated in another prey?predator system. In the second experiment, wild T. castaneum beetles from populations with predators feigned death longer than wild beetles from predator‐free populations. Combining the results from these two experiments with those from previous studies provided strong evidence that predators drive the evolution of longer death feigning. en-copyright= kn-copyright= en-aut-name=KonishiKana en-aut-sei=Konishi en-aut-mei=Kana kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SakunoWataru en-aut-sei=Sakuno en-aut-mei=Wataru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Environmental and life Science, Okayama University kn-affil= en-keyword= Amphibolus venator kn-keyword= Amphibolus venator en-keyword= antipredator behaviour kn-keyword= antipredator behaviour en-keyword= artificial selection kn-keyword= artificial selection en-keyword= locomotor activity kn-keyword= locomotor activity en-keyword= thanatosis kn-keyword= thanatosis en-keyword= tonic immobility kn-keyword= tonic immobility en-keyword= Tribolium freemani kn-keyword= Tribolium freemani END start-ver=1.4 cd-journal=joma no-vol=38 cd-vols= no-issue= article-no= start-page=233 end-page=239 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200314 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Relationships between mating tactics and male traits such as body size and fluctuating asymmetry in the Japanese scorpionfly en-subtitle= kn-subtitle= en-abstract= kn-abstract=Fluctuating asymmetry (FA) is defined as small, random deviations from perfect bilateral symmetry in a morphological trait. It has sometimes been used as an indicator of male quality because it affects male mating success. In the Japanese scorpionfly, Panorpa japonica, males are known to use two mating tactics, donation of nuptial gifts and forced mating. In P. japonica, low FA males are more likely to win a competition with another male, and females prefer low FA male sex pheromones. However, no studies have been conducted on the effect of FA on the mating tactics adopted by males. In the present study, we first observed the mating behaviors of P. japonica and classified these into three patterns: (1) nuptial gifting, (2) forced mating, and (3) feeding mating. Second, we investigated the relationships between mating tactics and male traits, including body size, FA, and weapon size. The results showed a positive correlation between absolute FA and mating duration only in the case of feeding mating. We discuss the reasons why this significant correlation was found in P. japonica. en-copyright= kn-copyright= en-aut-name=IshiharaRyo en-aut-sei=Ishihara en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil=raduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and life Science, Okayama University kn-affil= en-keyword=Copulation kn-keyword=Copulation en-keyword=Courtship kn-keyword=Courtship en-keyword=Mating duration kn-keyword=Mating duration en-keyword=Panorpa japonica kn-keyword=Panorpa japonica END start-ver=1.4 cd-journal=joma no-vol=38 cd-vols= no-issue=1 article-no= start-page=14 end-page=22 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190228 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Individual and Sexual Differences in Time to Habituate to Food-stimuli Presentation of Potential Prey in Hyla japonica en-subtitle= kn-subtitle= en-abstract= kn-abstract= The traits of many animal species exhibit individual and sexual differences. Individuals repeatedly receiving a stimulus without harm become habituated to it. However, few studies have been conducted on individual and sexual differences in the process of habituation to unfamiliar food stimuli. Therefore, we hypothesized that individual differences or sexual differences would be observed in reaction to an in-lab food-stimuli presentation of potential prey items (after that "food stimuli"). We tested the hypothesis using the Japanese tree frog Hyla japonica, and conducted statistical analyses of these results. A generalized linear model (GLM) showed individual and sexual differences in time to get used to the food stimuli. Females habituated more rapidly to food stimuli than males. The difference between sexes is discussed in view of two ultimate and one proximate reasons. en-copyright= kn-copyright= en-aut-name=TanabeShintaro en-aut-sei=Tanabe en-aut-mei=Shintaro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KasuyaEiiti en-aut-sei=Kasuya en-aut-mei=Eiiti kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Department of Biology, Faculty of Sciences, Kyushu University kn-affil= affil-num=3 en-affil=Graduate School of Environmental and life Science, Okayama University kn-affil= en-keyword=Habituation kn-keyword=Habituation en-keyword=Hyla japonica kn-keyword=Hyla japonica en-keyword=individual variation kn-keyword=individual variation en-keyword=sexual difference kn-keyword=sexual difference en-keyword=predation kn-keyword=predation END start-ver=1.4 cd-journal=joma no-vol=157 cd-vols= no-issue=1 article-no= start-page=17 end-page=31 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=201910 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Lines selected for different durations of tonic immobility have different leg lengths in the red flour beetle Tribolium castaneum en-subtitle= kn-subtitle= en-abstract= kn-abstract= Tonic immobility is an adaptive anti-predator behaviour observed in many species. This anti-predator behaviour is often correlated with a species' movement motivation, so a relationship between the duration of tonic immobility and morphological traits supporting movement would be expected. Using the red flour beetle, Tribolium castaneum, we carried out two-way artificial selection for the duration of tonic immobility over more than 43 generations, establishing populations with longer (L) and shorter (S) tonic immobility durations compared to those of a non-selected control (C) population. Here, we investigated differences in walking motivation and leg length between the selected populations. Walking motivation was significantly higher in beetles from the S population than that in those from the L population. Moreover, S-population beetles of both sexes had significantly longer legs than those from L and C populations. The present results suggest the evolution of longer legs in response to selection pressure for a shorter duration of tonic immobility in T. castaneum. en-copyright= kn-copyright= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil=Graduate School of Environmental and life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and life Science, Okayama University kn-affil= en-keyword=anti-predator strategy kn-keyword=anti-predator strategy en-keyword=tonic immobility kn-keyword=tonic immobility en-keyword=artificial selection kn-keyword=artificial selection en-keyword=leg kn-keyword=leg en-keyword=Tribolium castaneum kn-keyword=Tribolium castaneum END start-ver=1.4 cd-journal=joma no-vol=36 cd-vols= no-issue=2 article-no= start-page=161 end-page=168 dt-received= dt-revised= dt-accepted= dt-pub-year=2018 dt-pub=20180404 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Responses to relaxed and reverse selection in strains artificially selected for duration of death-feigning behavior in the red flour beetle, Tribolium castaneum en-subtitle= kn-subtitle= en-abstract= kn-abstract= Divergent lines selected artificially for many generations make it possible to answer two questions: (1) whether genetic variation still exists within the selected population; and (2) whether the selection itself is costly for the selected strain. In previous studies, the red flour beetle Tribolium castaneum was divergently selected artificially for duration of death-feigning, and strains selected for longer (L-strain) and shorter (S-strain) durations of death-feigning have been established (Miyatake et al. 2004, 2008). Because the selection experiments have been conducted for more than 27 generations, genetic variation may be eroded. Furthermore, because another previous study reported physiological costs to L-strains, the L-strains selected artificially for longer duration of death-feigning may have suffered more costs than the S-strains. In the present study, therefore, we relaxed the selection pressure after the 27th or 30th generation of S- and L-strains. We also carried out reverse selection during the most recent eight generations of S- and L-strains. The results showed that each strain clearly responded to relaxation of selection and reverse selection, suggesting that (1) additive genetic variation still existed in both strains after long-term selection, and (2) selection for shorter and longer duration of death-feigning was costly. These results suggest that anti-predator behavior is controlled by many loci, and longer or shorter duration of death-feigning is costly in a laboratory without predators. en-copyright= kn-copyright= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=Artificial selection kn-keyword=Artificial selection en-keyword=Quantitative trait kn-keyword=Quantitative trait en-keyword=Relaxation of selection kn-keyword=Relaxation of selection en-keyword=Reverse selection kn-keyword=Reverse selection en-keyword=Tonic immobility kn-keyword=Tonic immobility en-keyword=Tribolium castaneum kn-keyword=Tribolium castaneum END start-ver=1.4 cd-journal=joma no-vol=30 cd-vols= no-issue=6 article-no= start-page=1522 end-page=1529 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190705 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Artificial selection on walking distance suggests a mobility-sperm competitiveness trade-off en-subtitle= kn-subtitle= en-abstract= kn-abstract= Securing matings is a key determinant of fitness, and in many species, males are the sex that engages in mate searching. Searching for mates is often associated with increased mobility. This elevated investment in movement is predicted to trade-off with sperm competitiveness, but few studies have directly tested whether this trade-off occurs. Here, we assessed whether artificial selection on mobility affected sperm competitiveness and mating behavior, and if increased mobility was due to increased leg length in red flour beetles (Tribolium castaneum). We found that, in general, males selected for decreased mobility copulated for longer, stimulated females more during mating, and tended to be better sperm competitors. Surprisingly, they also had longer legs. However, how well males performed in sperm competition depended on females. Males with reduced mobility always copulated for longer than males with high mobility, but this only translated into greater fertilization success in females from control populations and not the selection populations (i.e. treatment females). These results are consistent with a mate-searching/mating-duration trade-off and broadly support a trade-off between mobility and sperm competitiveness. en-copyright= kn-copyright= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=ArcherC Ruth en-aut-sei=Archer en-aut-mei=C Ruth kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=Hosken David J en-aut-sei=Hosken en-aut-mei= David J kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Centre for Ecology & Conservation, University of Exeter kn-affil= affil-num=3 en-affil=Centre for Ecology & Conservation, University of Exeter kn-affil= affil-num=4 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=leg length kn-keyword=leg length en-keyword=mate searching kn-keyword=mate searching en-keyword=morphology kn-keyword=morphology en-keyword=sperm competition, kn-keyword=sperm competition, en-keyword=trade-off kn-keyword=trade-off en-keyword=Tribolium castaneum kn-keyword=Tribolium castaneum en-keyword=walking kn-keyword=walking END start-ver=1.4 cd-journal=joma no-vol=49 cd-vols= no-issue=5 article-no= start-page=478 end-page=483 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190621 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Arousal from Tonic Immobility by Vibration Stimulus en-subtitle= kn-subtitle= en-abstract= kn-abstract= Tonic immobility (TI) is an effective anti-predator strategy. However, long immobility status on the ground increases the risk of being eaten by predators, and thus insects must rouse themselves when appropriate stimulation is provided. Here, the strength of vibration causing arousal from the state of TI was examined in strains artificially selected for longer duration of TI (L-strains: long sleeper) in a beetle. We provided different strengths of vibration stimuli to the long sleepers in Tribolium castaneum. Although immobilized beetles were never awakened by the stimuli from 0.01 to 0.12 mm in amplitude, almost of the beetles were aroused from immobilized status by the stimulus at 0.21 mm. There was a difference in sensitivity of individuals when the stimuli of 0.14 mm and 0.18 mm were provided. F2 individuals were also bred by crossing experiments of the strains selected for shorter and longer duration of TI. The arousal sensitivity to vibration was well separated in the F2 individuals. A positive relationship was observed between the duration of TI and the vibration amplitude, suggesting that immobilized beetles are difficult to arouse from a deep sleep, while light sleepers are easily aroused by even small vibrations. The results indicate a genetic basis for sensitivity to arousal from TI. en-copyright= kn-copyright= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KitayamaRyota en-aut-sei=Kitayama en-aut-mei=Ryota kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=OtsukiKeiichi en-aut-sei=Otsuki en-aut-mei=Keiichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=JiYuhao en-aut-sei=Ji en-aut-mei=Yuhao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=FujisawaRyusuke en-aut-sei=Fujisawa en-aut-mei=Ryusuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=NagayaNaohisa en-aut-sei=Nagaya en-aut-mei=Naohisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Department of Evolutionary Ecology, Graduate School of Environmental and Life ScienceOkayama University kn-affil= affil-num=2 en-affil=Department of Evolutionary Ecology, Graduate School of Environmental and Life ScienceOkayama University kn-affil= affil-num=3 en-affil=Department of Evolutionary Ecology, Graduate School of Environmental and Life ScienceOkayama University kn-affil= affil-num=4 en-affil=Faculty of Computer Science and Engineering Kyoto Sangyo University kn-affil= affil-num=5 en-affil=Department of Evolutionary Ecology, Graduate School of Environmental and Life ScienceOkayama University kn-affil= affil-num=6 en-affil=School of Computer Science and Systems EngineeringKyushu Institute of Technology kn-affil= affil-num=7 en-affil=Faculty of Computer Science and Engineering Kyoto Sangyo University kn-affil= en-keyword=Beetle kn-keyword=Beetle en-keyword=Crossing experiment kn-keyword=Crossing experiment en-keyword=Death feigning kn-keyword=Death feigning en-keyword=Selection experiment kn-keyword=Selection experiment en-keyword=Thanatosis kn-keyword=Thanatosis en-keyword=Tribolium kn-keyword=Tribolium END start-ver=1.4 cd-journal=joma no-vol=54 cd-vols= no-issue= article-no= start-page=459 end-page=464 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190913 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effects of temperature during successive generations on life-history traits in a seed beetle Callosobruchus chinensis (Chrysomelidae: Coleoptera) en-subtitle= kn-subtitle= en-abstract= kn-abstract= Temperature is an important environmental factor for life-history traits in poikilothermic animals. Many of experiments on evolution have been conducted using Drosophila species, and effects on life-history traits vary depending on the study. On the other hand, few studies have been conducted on the effects of temperature on life-history traits in the other insect species. In the present study, we reared adzuki bean beetles under two different temperatures, high and low, for 2 years (20 generations), and compared life-history traits including body size of females, fecundity, egg size, rate of egg hatching, emergence rate, development time, and wing length. No differences in responses were found in these traits between selection strains, except the rate of egg hatching. That is, the rates of egg hatching in high-temperature (32 °C) selection strains were significantly higher than those in low-temperature (24 °C) selection strains. We discuss the cause of change in egg hatchability during successive generations under different temperature treatments from the following viewpoints including evolutionary adaptation to high temperature and the experimental protocol. en-copyright= kn-copyright= en-aut-name=TeradaKenji en-aut-sei=Terada en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Environmental and Life ScienceOkayama University kn-affil= en-keyword=Temperature kn-keyword=Temperature en-keyword=Experimental evolution kn-keyword=Experimental evolution en-keyword=Hatching rate Seed beetle kn-keyword=Hatching rate Seed beetle en-keyword=Callosobruchus chinensis kn-keyword=Callosobruchus chinensis END start-ver=1.4 cd-journal=joma no-vol=9 cd-vols= no-issue=1 article-no= start-page=14001 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190930 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Transcriptomic comparison between beetle strains selected for short and long durations of death feigning en-subtitle= kn-subtitle= en-abstract= kn-abstract= The molecular basis of death feigning, an antipredator behavior that has received much attention recently, was analyzed. We compared the gene expression profiles of strains with different behaviors, i.e., different durations of death feigning, in the beetle Tribolium castaneum. Beetles artificially selected for short (S) and long (L) durations of death feigning for many generations were compared thoroughly by RNA sequencing. We identified 518 differentially expressed genes (DEGs) between the strains. The strains also showed divergence in unexpected gene expression regions. As expected from previous physiological studies, genes associated with the metabolic pathways of tyrosine, a precursor of dopamine, were differentially expressed between the S and L strains; these enzyme-encoding genes were expressed at higher levels in the L strain than in the S strain. We also found that several genes associated with insulin signaling were expressed at higher levels in the S strain than in the L strain. Quantitative real-time PCR analysis showed that the relative expression levels of Tchpd (encoding 4-hydroxyphenylpyruvate dioxygenase, Hpd) and Tcnat (encoding N-acetyltransferase, Nat) were significantly higher in the L strain than in the S strain, suggesting the influence of these enzymes on the supply of dopamine and duration of death feigning. en-copyright= kn-copyright= en-aut-name=UchiyamaHironobu en-aut-sei=Uchiyama en-aut-mei=Hironobu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SasakiKen en-aut-sei=Sasaki en-aut-mei=Ken kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HinosawaShogo en-aut-sei=Hinosawa en-aut-mei=Shogo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=TanakaKeisuke en-aut-sei=Tanaka en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MatsumuraKentarou en-aut-sei=Matsumura en-aut-mei=Kentarou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=YajimaShunsuke en-aut-sei=Yajima en-aut-mei=Shunsuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=NODAI Genome Research Center, Tokyo University of Agriculture kn-affil= affil-num=2 en-affil=Graduate School of Agriculture, Tamagawa University kn-affil= affil-num=3 en-affil=Graduate School of Agriculture, Tamagawa University kn-affil= affil-num=4 en-affil=NODAI Genome Research Center, Tokyo University of Agriculture kn-affil= affil-num=5 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=7 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=8 cd-vols= no-issue=12 article-no= start-page=e83278 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2013 dt-pub=20131227 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Male Courtship Behavior and Weapon Trait as Indicators of Indirect Benefit in the Bean Bug, Riptortus pedestris en-subtitle= kn-subtitle= en-abstract= kn-abstract=Females prefer male traits that are associated with direct and/or indirect benefits to themselves. Male?male competition also drives evolution of male traits that represent competitive ability. Because female choice and male?male competition rarely act independently, exploring how these two mechanisms interact is necessary for integrative understanding of the evolution of sexually selected traits. Here, we focused on direct and indirect benefits to females from male attractiveness, courtship, and weapon characters in the armed bug Riptortus pedestris. The males use their hind legs to fight other males over territory and perform courtship displays for successful copulation. Females of R. pedestris receive no direct benefit from mating with attractive males. On the other hand, we found that male attractiveness, courtship rate, and weapon size were significantly heritable and that male attractiveness had positive genetic covariances with both courtship rate and weapon traits. Thus, females obtain indirect benefits from mating with attractive males by producing sons with high courtship success rates and high competitive ability. Moreover, it is evident that courtship rate and hind leg length act as evaluative cues of female choice. Therefore, female mate choice and male?male competition may facilitate each other in R. pedestris. This is consistent with current basic concepts of sexual selection. en-copyright= kn-copyright= en-aut-name=SuzakiY? en-aut-sei=Suzaki en-aut-mei=Y? kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KatsukiMasako en-aut-sei=Katsuki en-aut-mei=Masako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=OkadaYasukazu en-aut-sei=Okada en-aut-mei=Yasukazu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Environmental Science, Okayama University affil-num=2 en-affil= kn-affil=Faculty of Life and Environmental Science, University of Tsukuba affil-num=3 en-affil= kn-affil=Graduate School of Environmental and Life Science, Okayama University affil-num=4 en-affil= kn-affil=Department of General Systems Studies, University of Tokyo END start-ver=1.4 cd-journal=joma no-vol=25 cd-vols= no-issue=1 article-no= start-page=49 end-page=55 dt-received= dt-revised= dt-accepted= dt-pub-year=2007 dt-pub=20071001 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Interpopulation variation in female remating is attributable to female and male effects in Callosobruchus chinensis en-subtitle= kn-subtitle= en-abstract= kn-abstract=

The evolution of female multiple mating is best understood by consideration of male and female reproductive perspectives. Females should usually be selected to remate at their optimum frequencies whereas males should be selected to manipulate female remating to their advantage. Female remating behavior may therefore be changed by variation of male and female traits. In this study, our objective was to separate the effects of female and male strains on female remating for the adzuki bean beetle, Callosobruchus chinensis, for which there is interstrain variation in female remating frequency. We found that interstrain variation in female remating is primarily attributable to female traits, suggesting genetic variation in female receptivity to remating in C. chinensis. Some interstrain variation in female remating propensity was attributable to an interaction between female and male strains, however, with the males of some strains being good at inducing nonreceptivity in females from one high-remating strain whereas others were good at inducing copulation in nonvirgin females from the high-remating strain. There is, therefore, interstrain variation in male ability to deter females from remating and in male ability to mate successfully with nonvirgin females. These results suggest that mating traits have evolved along different trajectories in different strains of C. chinensis.

en-copyright= kn-copyright= en-aut-name=HaranoTomohiro en-aut-sei=Harano en-aut-mei=Tomohiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil=Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and life Science, Okayama University kn-affil= en-keyword=polyandry kn-keyword=polyandry en-keyword=multiple mating kn-keyword=multiple mating en-keyword=sexual conflict kn-keyword=sexual conflict en-keyword=sexual selection kn-keyword=sexual selection en-keyword=genetic variation kn-keyword=genetic variation en-keyword=Callosobruchus chinensis kn-keyword=Callosobruchus chinensis END start-ver=1.4 cd-journal=joma no-vol=25 cd-vols= no-issue=3 article-no= start-page=255 end-page=261 dt-received= dt-revised= dt-accepted= dt-pub-year=2007 dt-pub=20071001 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Ownership-dependent mating tactics of minor males of the beetle Librodor japonicus (Nitidulidae) with intra-sexual dimorphism of mandibles en-subtitle= kn-subtitle= en-abstract= kn-abstract=

Intra-sexual dimorphism is found in the weapons of many male beetles. Different behavioral tactics to access females between major and minor males, which adopt fighting and alternative tactics, respectively, are thought to maintain the male dimorphism. In these species major males have enlarged weapons that they use in fights with rival males. Minor males also have small weapons in some of these species, and it is unclear why these males possess weapons. We examined the hypothesis that minor males might adopt a fighting tactic when their status was relatively high in comparison with that of other males (e.g., ownership of a territory). We observed the behavioral tactics of major and minor males of the beetle Librodor japonicus, whose males have a dimorphism of their mandibles. Major males fought for resources, whereas minor males adopted two status-dependent tactics, fighting and sneaking, to access females, depending on their ownership of a sap site. We suggest that ownership status-dependent mating tactics in minor males may maintain the intra-sexual dimorphism in this beetle.

en-copyright= kn-copyright= en-aut-name=OkadaKensuke en-aut-sei=Okada en-aut-mei=Kensuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil= en-keyword=allometry kn-keyword=allometry en-keyword=alternative phenotype kn-keyword=alternative phenotype en-keyword=exaggerated trait kn-keyword=exaggerated trait en-keyword=male competition kn-keyword=male competition en-keyword=status-dependent selection kn-keyword=status-dependent selection END start-ver=1.4 cd-journal=joma no-vol=91 cd-vols= no-issue=1 article-no= start-page=61 end-page=69 dt-received= dt-revised= dt-accepted= dt-pub-year=2002 dt-pub=200202 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Genetic Quality Control in Mass-Reared Melon Files kn-title=大量増殖されたウリミバエの遺伝的虫質管理 en-subtitle= kn-subtitle= en-abstract=ウリミバエ根絶後の大量増殖における虫質管理について,人為選択実験の結果に基づいて考察した.まずミバエ類の大量増殖における虫質管理の簡単な歴史について触れた.沖縄県で現在飼育されている大量増殖虫は,野生虫と比べて多くの形質が異なっている.そこで現在飼育されている大量増殖虫の特質を明らかにし,なぜそのような違いが生じたのかについて考えた.その結果,形質の変化には大量増殖方法による選択圧が大きく関与していると考えられた.そこで,大量増殖虫のいくつかの形質に対する人為選択実験の結果をレビューした.さらに,大量増殖虫の繁殖と寿命に関わる形質を人為的に操作することに成功した沖縄県の事例を紹介した.以上の結果をふまえて,ウリミバエ根絶後の大量増殖における虫質管理の方向性について考察した. kn-abstract=Quality control in mass-reared melon files, Bactricera cucurbitae, after eradication is discussed, based on the results of artificial selection experiments. First, a brief history of quality control in mass-rearing of insects is described. In practical mass-rearing of melon fly, many traits habe already been differentiated between mass-reared and wild files. These differing traits are reviewed and the factors which caused these differences are considered. It was considered that the differences between wild and mass-reared melon files depended on the selection pressures from the mass-rearing method. Next, the results of several artificial selection experiments using the melon fly are reviewed. Finally, consideration is given to some correlated responses to artificial selection in mass-rearing. Longevity that is correlated to early fecundity was successfully controlled by artificial selection for reproduction in the mass-rearing system. On the basis of these results, an improved method for quality control in mass-reared melon fly with considerations for quantitative genetics is discussed. en-copyright= kn-copyright= en-aut-name=MiyatakeTakahisa en-aut-sei=Miyatake en-aut-mei=Takahisa kn-aut-name=宮竹貴久 kn-aut-sei=宮竹 kn-aut-mei=貴久 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 en-keyword=Bactrocera cucurbitae kn-keyword=Bactrocera cucurbitae en-keyword=eradication kn-keyword=eradication en-keyword=genetic correlation kn-keyword=genetic correlation en-keyword=mass-rearing kn-keyword=mass-rearing en-keyword=selection kn-keyword=selection END