Population differences in reproductive resource allocation and heterosis in the invasive vector Aedes albopictus

Background: An understanding of the traits that favour biological invasions has been considered to be an essential step in predicting which species would become successful invaders. Classical approaches test for differences between invasive versus non-invasive species and emphasize reproduction as a critical phenotype for successful establishment of an invasive species. However, cross-species comparisons underestimate intra-species differences, which may be relevant in species with complex invasion histories. Methods: We capitalize on the well-characterized invasion history of the arboviral vector Aedes albopictus, which has resulted in genetically distinct native, old and invasive populations, and compared the reproductive capacity (fertility and fecundity), development (timing of egg hatching, oviposition patterns and egg hatching) and physiology (blood digestion and nutrient movement during oogenesis) across populations. Results: The results show that invasive populations are larger in size compared to the Ae. albopictus reference Foshan population and have a higher reproductive output than both an old population and the reference Foshan population. The higher reproductive capacity of invasive mosquitoes has both a physiological and genetic basis, and is accompanied by hybrid vigour, albeit at varying degrees across populations. Conclusions: These findings highlight population-level differences in reproductive traits of Ae. albopictus populations that may be associated with their invasion success.