Conserved role of juvenile hormone in regulating behavioural maturation and division of labour in a highly eusocial wasp

Juvenile hormone (JH) in insects plays a key role in regulating reproduction, but in some social insects it has also acquired secondary functions in regulating the age-related division of labour among the workers. Previous work has shown that JH regulates division of labour in honey bees, in several prim-itively eusocial paper wasps and in leafcutter ants, which comprise three independent origins of sociality. It remains unclear, however, to what degree JH could have a conserved role in regulating division of labour within these clades. To this end, we investigated whether JH also regulates division of labour in the highly eusocial Vespine wasp Vespula vulgaris, in which JH had previously been shown only to regulate reproduction and affect queen pheromone signalling. In line with JH having a conserved role in regulating division of labour in social wasps, we show that JH in this species indeed affected behavioural maturation and division of labour in the worker caste. In particular, topical application of the JH analogue methoprene onto workers accelerated behavioural maturation and hastened the onset of foraging, thereby significantly decreasing the time they spent conducting activities inside the nest. We discuss how this conserved role of JH in regulating division of labour could indicate the same conserved genetic toolkits being used to regulate division of labour across several independent origins of sociality. In addition, we examine the implications of JH having several pleiotropic effects in this species and discuss whether this could constrain the expression of reproductive conflicts in their societies.(c) 2023 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Automated summary

The juvenile hormone (JH) plays important roles in regulating reproduction and age-related division of labor in social insects. This study shows that JH also regulates behavioral maturation and division of labor in the highly eusocial Vespine wasp Vespula vulgaris.