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The yellow paper wasp (Polistes versicolor) was first recorded in Galapagos on Floreana Island in 1988, probably entering by cargo ship. Currently, it is one of the most invasive insects in Galapagos. It is a voracious predator of larvae and adults of other insects and competes for this resource with endemic and native insectivorous vertebrates of the islands. It also visits and collects nectar from flowers in search of sugars, which has made it a dominant pollinator.
Control methods for P. versicolor tested to date have not been effective in reducing wasp numbers in the long term. For this reason, researchers from the Charles Darwin Foundation (CDF), in collaboration with the Galapagos National Park Directorate (GNPD), are investigating baits that can be transported by wasps to their nests to kill developing larvae.
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The diet of P. versicolor is made up mainly of lepidopteran larvae (butterflies and moths). It has been estimated that they capture an average of 16 medium to large moth larvae per day to feed a nest of 120 to 150 wasp larvae. Its diet represents strong competition for resources for 15 species of land birds, 9 species of geckos, and 9 species of lizards. They have also been recorded visiting flowers of at least 93 plant species in Galapagos, including 27 introduced species. Studies are required to confirm the degree of competition with native pollinators.
Nest of the yellow paper wasp Polistes versicolor. Photo: Juan Manuel García, CDF.
CDF researchers, in collaboration with the GNPD, coordinate efforts to develop a bait that is attractive to P. versicolor and that, together with an insecticide, can be transported to the nest and shared with larvae and other members of the colony.
Our main objective is to have an effective tool to reduce the impact of the yellow paper wasp, Polistes versicolor, with low risk to non-target species.
Laboratory tests carried out by CDF scientists have shown that the bait based on bananas, sugar and hydrolyzed protein is attractive to this species of wasp. Likewise, observations of their behavior show that the wasps transport the bait with their jaws or regurgitate it to feed their larvae and other members of the colony (trophallaxis).
Wasps sharing food by trophallaxis. Photo: Juan Manuel Garcia, CDF.
Scientists are currently conducting trials to improve the attraction of the bait to wasps, identify the proper concentration of insecticide to be combined with the bait, and assess whether the bait is effective in killing the colony and whether it can be attracted and ingested by non-target species.
Research assistant setting baited traps in the field. Photo: Jacqueline Rodríguez, CDF.
Installation of a wasp nest in a breeding cage. Photo: Julia Bolaños, CDF.
On the other hand, a recent study with collaborators from the University of Victoria, Wellington, found that extracts (semiochemicals) from the head and thorax of female P. versicolor could serve as potential species-specific baits for this species. With this information, and the results obtained from the investigations being carried out at the CDF, it is expected to develop a specific bait for P. versicolor, which can be used in traps to control populations of this species..
Keywords: bait, control, wasp, non-target species
Bulgarella, M., Mieles, A. E., Rodríguez, J., Campaña, Y., Richardson, G. M., Keyzers, R. A., Causton, C. E., & Lester, P. J. (2022). Integrating biochemical and behavioral approaches to develop a bait to manage the invasive yellow paper wasp Polistes versicolor (Hymenoptera, Vespidae) in the Galápagos Islands. Neotropical Biodiversity, 8(1), 271–280. https://doi.org/10.1080/23766808.2022.2098575
Hervías-Parejo, S., & Traveset, A. (2018). Pollination effectiveness of opportunistic Galápagos birds compared to that of insects: From fruit set to seedling emergence. American Journal of Botany, 105(7), 1142–1153. https://doi.org/10.1002/ajb2.1122
Linsey, E., Rick, C., & Stephens, S. (1996). Observations on the floral relationships of the Galápagos carpenter bee (Hymenoptera: Apidae). Pan-Pac. Entomol, 42, 1–18.
Mieles, A. (2021). Reporte de avances de proyecto Establecimiento de Métodos para el Control de la Avispa Invasora Polistes versicolor en las Islas Galápagos. Fundación Charles Darwin.
Parent, C. E., Peck, S. B., Causton, C. E., Roque-Albelo, L., Lester, P. J., & Bulgarella, M. (2020). Polistes versicolor (Hymenoptera: Vespidae), an Introduced Wasp in the Galapagos Islands: Its Life Cycle and Ecological Impact. Environmental Entomology, 49(6), 1480–1491. https://doi.org/10.1093/ee/nvaa110
These studies are being carried out in collaboration with the Galapagos National Park Directorate, the University Victoria of Wellington, the Universidad del Sur de Manabí, and the Escuela Superior Politécnica de Chimborazo, Ecuador.