Venom volatiles of the paper wasp social parasite <Emphasis Type="Italic">Polistes sulcifer</Emphasis> elicit intra-colonial aggression on the nest of the host species <Emphasis Type="Italic">Polistes dominulus</Emphasis>

Insect social parasites rely on host workers to rear and protect their own brood. To conquer a host colony, a parasite must overcome the defensive mechanisms of the host, often by exploiting its chemical communication system. A widespread strategy involves the production of specific allomones (the so-called “propaganda pheromones”) to facilitate the usurpation process by manipulating the defensive behavior of the host. Polistes sulcifer is the obligate and permanent social parasite of the congeneric paper wasp Polistes dominulus. In this study, we investigated if the venom volatiles, well known to be alarm pheromones in the host species, could be used by the parasite to manipulate the host defense. We thus performed laboratory bioassays, to evaluate the possible effect of the venom volatile compounds of the parasite on the host. Our results show that host colony members reacted to the venom volatiles extract of the parasite with an increase in intra-colonial aggression compared to the reaction induced by the venom volatiles extract of the host foundress. Besides, a re-analysis of previously published chemical data showed that the parasite venom volatiles profile differs from that of the host: the spiroacetals are absent, whilst the amides are very abundant in the parasite venom when compared with that of the host. Similar to other insect social parasites, Polistes wasp parasites might be able to increase their invasion success by using venom volatile pheromones to distract the host defenders.