CONICET | Buscador de Institutos y Recursos Humanos

Zaprionusindianus is a fly species native to the Afrotropical biogeographic region thatinvaded the South American continent 20 years ago. From its initial report inBrazil, its southernmost record in the South American continent is around alatitude of 34 degrees south in areas with temperate climates with cold winters.We aimed to search for traits responses to winter like abiotic conditions thatmay be relevant in Z. indianus invasion towards the southern boundaries of itsdistribution in the South American continent. For this we performed acharacterization of female reproductive traits (ovarian maturation andfertility) and survival in response to cold treatments with summer and winterphotoperiods. Overwintering survival and fertility were also compared betweennative and invasive range wild-derived flies. Results showed that Z. indianusfemales arrested ovarian maturation followed by fertility recovery when exposedto hard abiotic conditions. Critical temperature for ovarian maturation of thisspecies is intermediate between tropical and temperate drosophilids species.Photoperiod acted as modulator of ovarian maturation arrest, but only forinvaded range flies. Intraspecific differences among native and invaded fliesin overwintering performance of ovarian maturation and fertility do not supportthe hypothesis of local adaptations for invasive range populations. On thecontrary, a higher cold tolerance of native range is consistent with a scenarioof local adaptations or phenotypic plasticity in native range population. Allin all, we found a set of physiological tools considered as necessaryconditions for Z. indianus expansion to temperate and cold areas and alsoresults that are compatible with a limitation to the invasion process towardsouthern latitudes were also found.