Integrating biochemical and behavioral approaches to develop a bait to manage the invasive yellow paper wasp Polistes versicolor (Hymenoptera, Vespidae) in the Galápagos Islands

It is estimated that more than 500 species of insects have been introduced to the Galápagos Islands via human activities. One of these insect invaders is the yellow paper wasp, Polistes versicolor (Olivier) (Hymenoptera: Vespidae), a social wasp native to continental South America. In Galápagos, these wasps are voracious predators of insect larvae, compete with native species for insect prey or for floral resources and are a human nuisance. Wasp suppression methods currently in use are inefficient and attract non-target species, calling for the development of species-specific attractants that can be used in baits to lure and kill wasps. To evaluate the potential for using wasp semiochemicals in baits, we determined the biochemical composition of the head, thorax, Dufour's and venom glands of P. versicolor foragers via gas chromatography/mass spectrometry (GC/MS). Male and female wasps were tested for behavioral responses to body segment extracts from both sexes. Female body extracts consistently elicited more behavioral responses in both male and female wasps than male extracts. Females reacted to female head, thorax and abdomen (the Dufour's and venom glands are located in the abdomen) extracts, whereas males reacted significantly to female head and thorax extracts. One male body extract, the head, elicited two significant behaviors: female wasps groomed more often, and males touched the filter paper more often compared to the blank control. Head extracts consistently changed the behavior of female and male wasps and, together with female thorax extracts, have potential as species-specific lures for yellow paper wasps. Heads were mainly composed of hydrocarbon lipids and oleamide, a ligand for odorant-binding proteins. The thorax consisted of fatty aldehydes, long-chain alkanes and fatty amide lipids. Field trials of blends of these compounds in high wasp density areas of Galápagos are the next step to confirm if any of these compounds are attractive to P. versicolor. The yellow paper wasp, Polistes versicolor, is an invasive species in the Galápagos Islands. In addition to its ecological impact, this wasp is a nuisance to residents and visitors alike as they affect tourism and activities in human settlements. We studied the biochemical composition and behavior of P. versicolor wasps to find attractants (sex or aggregation pheromones) useful for developing baits or lures to control this pest. Panel a shows a P. versicolor nest built alongside a touristic