Juvenile hormone affects age polyethism, ovarian status and cuticular hydrocarbon profile in workers of the waspPolybia occidentalis

Abstract

Division of labor is one of the most striking features in the evolution of eusociality. Juvenile hormone (JH) mediates reproductive status and aggression among nestmates in primitively eusocial Hymenoptera (species without morphologically distinct castes). In highly social species it has apparently lost its gonadotropic role and primarily regulates the division of labor in the worker caste. Polybia occidentalis, a Neotropical swarm-founding wasp, is an ideal model to understand how JH levels mirror social context and reproductive opportunities because of the absence of a clear morphological caste dimorphism. In this study, we tested the hypothesis that JH influences division of labor, ovary activation and cuticular hydrocarbon profiles of workers. Our observations confirmed that JH analog (methoprene) and precocene affected the cuticular chemical profile associated with the age polyethism. Also, methoprene and precocene-I influenced differently ovarian activation of treated females (individuals treated with methoprene expressed more activated ovaries while precocene treatment did not have significant effect). These results suggest that different hormonal levels induce a differential expression in the cuticular chemical profiles associated with the workers’ age polyethism, which may be essential for keeping the social cohesion among workers throughout their lives in the colony. Furthermore, JH is likely to play a gonadotropic role in P. occidentalis. JH has apparently undergone certain modifications in social Hymenoptera, presenting multifaceted functions in different species.

Juvenile hormone modulates hydrocarbon expression and reproduction in the german wasp Vespula germanica

“…The chemical changes were more pronounced in the CHC samples, whereas the variation for egg and Dufour's gland samples were more subtle. These results provide additional support for the hypothesis that JH has pleiotropic properties, being responsible for regulating several processes in social wasps, such as ovary activation, behavioral maturation, oviposition, and the modulation of chemical compounds (Oliveira et al, 2017;Oi et al, 2021a,b;Prato et al, 2021). JH not only modulates the production of CHCs, as it has been previously demonstrated for wasp species (Oliveira et al, 2017;Oi et al, 2021a,b;Prato et al, 2021), but also can potentially modulate other components, such as the Dufour's gland composition.…”

“…Besides regulating chemical production, here we also report that JH has likely conserved gonadotropic effects in V. germanica, similar to its sister species V. vulgaris (Oliveira et al, 2017;Oi et al, 2020Oi et al, , 2021b. JH is responsible for regulating reproductive traits in primitively and swarmfounding wasp species (Tibbetts and Sheehan, 2012;Kelstrup et al, 2014;Walton et al, 2020;Prato et al, 2021) and in highly eusocial species. Altogether, JH may have a gonadotropicconserved function across the lineage of wasps.…”

“…In primitively eusocial species, JH displays a gonadotropic effect in females in Polistes annularis (Barth et al, 1975), Ropalidia marginata (Agrahari and Gadagkar, 2003), Polistes metricus (Tibbetts and Sheehan, 2012), Polistes canadensis (Giray et al, 2005), Polistes fuscatus (Walton et al, 2020), and Polistes dominula (Oi et al, 2021b); JH regulates behavior (onset of foraging and aggressive acts) in P. canadensis (Giray et al, 2005) and P. dominula (Shorter and Tibbetts, 2009;Tibbetts and Izzo, 2009;Tibbetts et al, 2013); and JH affects the production of chemical compounds in Mischocyttarus consimilis (Neves et al, 2020), P. dominula (Oi et al, 2021b), Polistes satan (Oi et al, 2021b), Mischocyttarus cassununga (Oi et al, 2021b;Ferreira et al, 2022), and Mischocyttarus cerberus (Ferreira et al, 2022). In swarm-founding species, JH has been reported to control behavioral maturation in Polybia occidentalis (Prato et al, 2021), and ovary activation and chemical expression of CHCs in P. occidentalis (Prato et al, 2021) and Synoeca surinama (Kelstrup et al, 2014). In highly eusocial wasps, JH effects have been well studied so far in a single species, namely Vespula vulgaris, and one of the roles is being associated with regulating reproductive traits in females, leading to modification of certain cuticular compounds over the cuticle (Oliveira et al, 2017;Oi et al, 2020Oi et al, , 2021a.…”

Early Life Exposure to Queen Mandibular Pheromone Mediates Persistent Transcriptional Changes in the Brain of Honey bee Foragers

“…To further investigate QMP treatment effects on specific genes, we focused on candidate genes involved in key individual and social behaviors and traits. We compiled lists of genes and molecular pathways associated with foraging behavior and division of labor in honey bees (52,(60)(61)(62)(63)(64)(65)(66)(67)(68)(69)(70)(71)(72)(73)(74). Furthermore, we searched for genes that play roles in aging (52,(75)(76)(77)(78), immunity (79,80), and reproduction (33,34), i.e.…”

A Technique for Transferring Nests of Polybia (Hymenoptera: Vespidae: Epiponini) Wasps in Anthropized Environment

“…During this process, there was only a small loss of individuals, the ones that already were over the nest surface when the procedure started. The nests that were transferred were monitored for one month to verify the efficiency of the procedure; furthermore, the P. occidentalis nests were used inother experiments, hence they were followed for three months (Prato, 2018;Prato et al, 2021).…”