Juvenile hormone regulates reproductive physiology and the production of fertility cues in the swarm-founding wasp Polybia occidentalis

Juvenile hormone (JH) has important functions that regulate insect life. In adult individuals, it induces gonadotropic and behavioral changes. Manipulating JH levels helps to understand how it influences insect physiology. The effects of JH on Epiponini swarm-founding wasps have shown contrasting results, affecting reproduction, chemical compound expression, behavior, and age polyethism. In this study, we investigated whether JH affects reproductive physiology and production of fertility cues in a swarm-founding wasp species Polybia occidentalis in an age-controlled experimental setup. We treated newly emerged females with methoprene (JH analogue) and precocene-I (JH inhibitor) to determine their effects on ovary activation and cuticular hydrocarbon (CHC) expression. Furthermore, we compared the chemical profiles of treated workers with those of queens. Our results show that methoprene and precocene-I affected the CHC production in P. occidentalis. Additionally, females treated with methoprene were chemically more similar to queens than precocene- and acetone-treated females. Methoprene affected ovarian status (increasing ovary activation). These results suggest that different levels of JH reflect changes in chemical and reproductive traits in P. occidentalis females. Furthermore, we point out the existence of fertility cues in this Epiponini wasp.