Highlights•Complementary sex determination leads to inbreeding costs in social
Hymenoptera.•Traits preserving sex locus diversity after founder events increase invasive
success.•Social and reproductive behaviours mitigate the impacts of low sex locus
diversity.•Secondary introductions or post-invasion mutations can restore sex locus
diversity.•Further research into CSD will result in greater understanding of invasion
dynamics.Invasive populations are often established from a small number of individuals, and …