Widespread polyandry in an invasive beetle species (Aethina tumida)

Biological invasions may induce adaptive shifts in traits that increase individual reproductive success, thereby accelerating population growth and amplifying ecological impacts. One such trait is polyandry, i.e. multiple mating by females, which may vary between endemic and invasive populations due to variation in demographic and environmental factors that alter the costs and benefits of multiple mating. Despite polyandry being widespread across taxa, comparative studies among multiple endemic and invasive populations of invasive species remain scarce. Here, we estimated the prevalence of polyandry in two endemic and five invasive populations of small hive beetle (Aethina tumida), a globally invasive parasite affecting bee health. Using DNA microsatellite genotyping of field-sampled females and their offspring to estimate mating frequencies, we show that polyandry varies in SHB populations and females mate with 1–13 males. However, the polyandry levels were not significantly different across the endemic and invasive populations compared. These results suggest that polyandry in SHB may be a stable reproductive trait rather than a plastic response to invasion-related factors. Our work supports further research on how multiple mating may improve both individual reproductive success and population viability in the context of biological invasions.