The role of priority effects in limiting the success of the invasive tiger mosquito, Aedes albopictus

Priority effects (PE), wherein species colonizing a habitat early have a negative impact on later colonizers, can have profound and legacy effects on community organization. In temperate zones, larval mosquito habitats are emptied each year in the winter and recolonized in the spring. There are phenological differences among common species but the role of PE in these communities is largely unexplored. Aedes albopictus, the invasive tiger mosquito, is considered a superior competitor to resident species during the larval phase when conditions are initiated with same-staged heterospecific larvae. However in nature, Ae. albopictus hatches, and resumes activity, later in the spring than other species, suggesting it encounters larger later developed individuals, and denser populations, of species such as Aedes triseriatus. Additionally, despite their competitive inferiority, these species often coexist with Ae. albopictus in larval habitats, with Ae. albopictus often occurring at relatively low abundances in sylvan habitats. Using lab and near field experiments, we tested the hypothesis that PE with early hatching species reduces survivorship and population growth for the invasive Ae. albopictus. When Ae. albopictus larvae encountered larger, later developed heterospecific larvae at greater densities, under controlled lab conditions and in artificial and natural mesocosms, they experienced significant reductions in survival and estimated finite rate of population increase. Additionally, we found that intraguild predation of Ae. triseriatus on Ae. albopictus may be an important mechanism through which PE works. We conclude that PE is a potential mechanism for coexistence between invasive and resident mosquitoes and should be further explored.