Lack of genetic structuring, low effective population sizes and major bottlenecks characterise common and German wasps in New Zealand

Invasive species cause severe ecological and economic impacts in their introduced ranges. Vespula wasps, native to Eurasia, are a major threat to New Zealand native ecosystems. Understanding factors that influence the success of wasp invasion is pivotal for the development of control strategies. Here, we compare genetic diversity and structure of Vespula germanica and Vespula vulgaris between regions of their native and introduced ranges using microsatellite markers. Our study found lower diversity and lack of genetic structure for both invasive Vespula species within New Zealand. The significant reduction in allelic richness, gene diversity and effective population size illustrate a major bottleneck in New Zealand V. germanica and V. vulgaris populations. Strong signatures of population structure were found for both Vespula species with two clusters being identified as optimal k, approximately corresponding to the native and the invaded ranges. Our results highlight the fact that the lack of genetic diversity does not impede successful invasions in V. germanica and V. vulgaris and encourage further research into mechanisms that promote the success of invasive social insects. Overall, this study provides insights into the genetics of invasive Vespula wasps that can be useful for the development of efficient management strategies.