Eusocial wasps are excellent models for understanding polyethism and division of labor among castes in social insects. However, little is known about the mechanisms controlling caste determination in eusocial wasps. E...Eusocial wasps are excellent models for understanding polyethism and division of labor among castes in social insects. However, little is known about the mechanisms controlling caste determination in eusocial wasps. Evidence suggests that the phenotype of queens in independent-founding (IF) eusocial wasps of the subfamily Polistinae can be partly fixed in the larval stage;however, this hypothesis has not yet been investigated. In this study we evaluate whether juvenile hormone (JH) affects pre-imaginal caste determination in the IF eusocial wasp Mischocyttarus consimilis (Hymenoptera: Vespidae). Analyzing morphometric and behavioral data, we demonstrated experimentally that females emerging from larvae that were treated with JH in the third instar had a significantly larger body size, spent more time in the nest, and were subject to less physical aggression from nestmates compared with females emerging from untreated control larvae. These results indicate that phenotype differences among castes in IF eusocial wasps can be partly fixed in the pre-adult stage and influenced by variations in the JH titer.展开更多
In social insects,it has been suggested that reproduction and the production of particular fertilitylinked cuticular hydrocarbons(CHC)may be under shared juvenile hormone(JH)control,and this could have been key in pre...In social insects,it has been suggested that reproduction and the production of particular fertilitylinked cuticular hydrocarbons(CHC)may be under shared juvenile hormone(JH)control,and this could have been key in predisposing such cues to later evolve into full-fledged queen pheromone signals.However,to date,only few studies have experimentally tested this“hormonal pleiotropy”hypothesis.Here,we formally test this hypothesis using data from four species of Polistine wasps,Polistes dominula,Polistes satan,Mischocyttarus metathoracicus,and Mischocyttarus cassununga,and experimental treatments with JH using the JH analogue methoprene and the anti-JH precocene.In line with reproduction being under JH control,our results show that across these four species,precocene significantly decreased ovary development when compared with both the acetone solvent-only control and the methoprene treatment.Consistent with the hormonal pleiotropy hypothesis,these effects on reproduction were further matched by subtle shifts in the CHC profiles,with univariate analyses showing that in P.dominula and P.satan the abundance of particular linear alkanes and mono-methylated alkanes were affected by ovary development and our hormonal treatments.The results indicate that in primitively eusocial wasps,and particularly in Polistes,reproduction and the production of some CHC cues are under joint JH control.We suggest that pleiotropic links between reproduction and the production of such hydrocarbon cues have been key enablers for the origin of true fertility and queen signals in more derived,advanced eusocial insects.展开更多
文摘Eusocial wasps are excellent models for understanding polyethism and division of labor among castes in social insects. However, little is known about the mechanisms controlling caste determination in eusocial wasps. Evidence suggests that the phenotype of queens in independent-founding (IF) eusocial wasps of the subfamily Polistinae can be partly fixed in the larval stage;however, this hypothesis has not yet been investigated. In this study we evaluate whether juvenile hormone (JH) affects pre-imaginal caste determination in the IF eusocial wasp Mischocyttarus consimilis (Hymenoptera: Vespidae). Analyzing morphometric and behavioral data, we demonstrated experimentally that females emerging from larvae that were treated with JH in the third instar had a significantly larger body size, spent more time in the nest, and were subject to less physical aggression from nestmates compared with females emerging from untreated control larvae. These results indicate that phenotype differences among castes in IF eusocial wasps can be partly fixed in the pre-adult stage and influenced by variations in the JH titer.
基金This research was funded by the Research Foundation Flanders to C.A.O.(postdoctoral fellowship FWO-12V6318N,international mobility grant FWO V449117N and research grant 1513219N)R.C.d.S.was funded by the S~ao Paulo Research Foundation(FAPESP)under the grant 2018/22461-3 and Coordenac¸~ao de Aperfeic¸oamento de Pessoal de Nı´vel Superior,Brasil(CAPES),Finance Code 001+1 种基金C.A.O.,H.M.F.,and T.W.were funded by the research grant(FWO-G064120N)All authors were funded by Bilateral grant FWO-FAPESP(FWO GOF8319N and FAPESP 2018/10996-0)。
文摘In social insects,it has been suggested that reproduction and the production of particular fertilitylinked cuticular hydrocarbons(CHC)may be under shared juvenile hormone(JH)control,and this could have been key in predisposing such cues to later evolve into full-fledged queen pheromone signals.However,to date,only few studies have experimentally tested this“hormonal pleiotropy”hypothesis.Here,we formally test this hypothesis using data from four species of Polistine wasps,Polistes dominula,Polistes satan,Mischocyttarus metathoracicus,and Mischocyttarus cassununga,and experimental treatments with JH using the JH analogue methoprene and the anti-JH precocene.In line with reproduction being under JH control,our results show that across these four species,precocene significantly decreased ovary development when compared with both the acetone solvent-only control and the methoprene treatment.Consistent with the hormonal pleiotropy hypothesis,these effects on reproduction were further matched by subtle shifts in the CHC profiles,with univariate analyses showing that in P.dominula and P.satan the abundance of particular linear alkanes and mono-methylated alkanes were affected by ovary development and our hormonal treatments.The results indicate that in primitively eusocial wasps,and particularly in Polistes,reproduction and the production of some CHC cues are under joint JH control.We suggest that pleiotropic links between reproduction and the production of such hydrocarbon cues have been key enablers for the origin of true fertility and queen signals in more derived,advanced eusocial insects.
