Coastal Restoration Trust of New Zealand

Coastal Dune Ecosystem Reference Database

Invasive paper wasp (Polistes chinensis) ecology and invertebrate conservation on Onetahua (Farewell Spit)

Author
Reason A
Year
2023
Journal / Source
MSc thesis
Publisher / Organisation
Victoria University of Wellington
Pages
115 pp
Summary
The Onetahua (Farewell Spit) Nature Reserve is a highly protected coastal site encompassing nationally rare habitat types and several at-risk plant and invertebrate species. During a 2019 BioBlitz, paper wasp abundance at this site was noted as likely threatening these diverse invertebrate communities. To inform decision-making on the potential need for local management of these wasps, I aimed to assess their distribution and population dynamics and identify species in their prey community. Over two austral summers, 2020 – 2021 and 2021 – 2022, I surveyed paper wasp colonies on Onetahua and tracked colony survival and development rates. Using wasp larvae gut samples, I conducted a CO1 metabarcoding analysis to identify prey species over a temporal gradient. During data and sample collection, I observed two species of entomopathogenic fungi fatally infecting P. chinensis wasps at their nests. Taking samples of these fungi, I identified each species using morphological and molecular methods, attempted to quantify their prevalence in the studied wasp population, and conducted infection bioassays with caged wasp nests to test fungal pathogenicity.