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

Juvenile hormone (JH) affects multiple physiological traits in insects. In social insects, besides development, JH has been demonstrated to influence caste determination and production of chemical compounds. In social wasps, JH triggers behavioural maturation, gonadotropic effects and hydrocarbons modulation. Here, we investigated whether JH displays the same function, previously shown in <em>Vespula vulgaris</em>, in females of the German wasp <em>Vespula germanica</em>. By experimentally treating workers with JH-analogue, an anti-JH, and acetone, we tested whether JH modulates the cuticular chemical expression (CHCs), the <em>Dufour</em> gland chemical composition<em>, </em>and hence the compounds found over egg’s surface. Additionally, we explored whether JH has a gonadotropic effect in workers. Workers treated with the JH-analogue acquired a chemical profile that made them resemble the queen. Interestingly, the same pattern was also seen in the <em>Dufour</em> glands and eggs, although more subtle. Furthermore, workers treated with the JH-analogue were more fertile than compared to the controls, supporting the fact that JH indeed acts as a gonadotropic hormone. Our results indicate a similar function of JH in the societies of related species <em>V. germanica</em> and <em>V</em>. <em>vulgaris</em>.