Comparison of overwintering survival and fertility between Zaprionus indianus (Diptera: Drosophilidae) flies from native and invaded range.

MENSCH, J.; LAVAGNINO, N. J.; FANARA, J. J.

Simposio; 8°International Symposium on the Environmental Physiology of Ectotherms and Plants; 2019

Zaprionus indianus is a fly species native to the Afrotropical biogeographic region that invaded the South American continent 20 years ago. From its initial report in Brazil, its southernmost record in the South American continent is around a latitude of 34 degrees south in areas with temperate climates with cold winters. We aimed to search for traits responses to winter like abiotic conditions that may be relevant in Z. indianus invasion towards the southern boundaries of its distribution in the South American continent. For this we performed a characterization of female reproductive traits (ovarian maturation and fertility) and survival in response to cold treatments with summer and winter photoperiods. Overwintering survival and fertility were also compared between native and invasive range wild-derived flies. Results showed that Z. indianus females arrested ovarian maturation followed by fertility recovery when exposed to hard abiotic conditions. Critical temperature for ovarian maturation of this species is intermediate between tropical and temperate drosophilids species. Photoperiod acted as modulator of ovarian maturation arrest, but only for invaded range flies. Intraspecific differences among native and invaded flies in overwintering performance of ovarian maturation and fertility do not support the hypothesis of local adaptations for invasive range populations. On the contrary, a higher cold tolerance of native range is consistent with a scenario of local adaptations or phenotypic plasticity in native range population. All in all, we found a set of physiological tools considered as necessary conditions for Z. indianus expansion to temperate and cold areas and also results that are compatible with a limitation to the invasion process toward southern latitudes were also found.