DNA metabarcoding of prey reveals spatial, temporal, and diet partitioning of an island ecosystem by four invasive wasps

1. Invasive alien species can cause detrimental changes in native ecosystems, but our understanding of the interactions between multiple exotic species is limited. To evaluate the joint effect of multiple sympatric invaders on an ecosystem, we must first understand how they interact with each other.

2. Here, we quantified the spatial distribution, dietary composition and overlap of four invasive generalist vespid species (two Vespula and two Polistes) that co-occur on Ahuahu off the north-east coast of New Zealand. We used DNA metabarcoding of larval faecal material to identify prey species, and mapped the locations of nests.

3. We observed clear spatial partitioning, with different wasp species aggregating in different habitats. Diet differed both among wasp species (diet partitioning) and among seasons (temporal partitioning). There was stronger competition (highest diet overlap) between V. germanica and V. vulgaris than between other wasp species, but partitioning resources min...