The native and exotic prey community of two invasive paper wasps (Hymenoptera: Vespidae) in New Zealand as determined by DNA barcoding

Social wasps are invasive in many regions around the world. In their new communities, introduced predators such as these wasps may be beneficial as consumers of exotic pests, but they will also consume native species. Here, we examined the diet of the exotic European paper wasp (Polistes dominula) and the closely related congener, Polistes chinensis, in a region of New Zealand where they co-occur. DNA barcoding was used to analyse their diet. The diet of both wasp species was largely Lepidopteran but other orders such as Hemiptera, Diptera and Coleoptera were also represented. Our analysis showed substantial site-to-site variation in diet. The two wasps differed significantly in their prey, although these differences appear to be driven by taxa identified from a small number of DNA reads in a small number of samples. Native and introduced fauna were represented in the diets of both wasps and included important agricultural pests. Of the 92 prey taxa able to be identified to species level, 81 were identified as exotic or introduced to New Zealand. The remaining 11 were species native to New Zealand. However, our estimates suggest over 50% of the prey DNA in the wasp diet is derived from native species. These wasps are abundant in some coastal and urban habitats, where they are likely to consume pest species as well as native species of conservation importance. The ecosystem services or costs and benefits provided by these invasive species are likely to be contingent on the prey communities and habitats they occupy.