INCREASED THERMOTOLERANCE TO HEAT BY SELECTING FOR MATING SUCCESS AT HIGH TEMPERATURE

NORRY F; STAZIONE L; SAMBUCETTI P

Foz do Iguacu, Paraná, Brazil

Congreso; XXII International Congress of Genetics (ICG), in Foz do Iguacu, Paraná, Brazil, September 10 to 14, 2018.; 2020

Reproductive fitness components such us mating success are strongly influenced by environmental temperature. Under the current scenario of global warming, the knowledge about how organisms? reproduction could be affected by thermal stress is a relevant issue for predicting potential evolutionary responses to increasing temperature. In this study, we evaluated the responses to artificial selection on mating success at high temperature in D. buzzatii and their effects on an ecologically relevant themotolerance trait, the knockdown resistance to high temperature (KRHT). Selected lines were generated in three replicates by allowing virgin flies to mate for four hours at 33 °C. Then, females were returned at 25 °C in empty bottles to lay eggs and obtain the next generation. Other three replicated lines were maintained at 25 °C as control. Once selection was finished, KRHT was measured as the time taken until flies were knocked down at 37 °C in a glass column. After ten generations of selection, selected lines showed higher mating success at 33 °C than control lines in a competitive assay. Furthermore, thermotolerance was also affected by selection as KRHT was higher in selected lines than in controls. The results show that mating success can evolve as response of increasing environmental temperature. This response could be partially explained by an indirect selection on thermotolerance phenotypes such us KRHT. Considering that reproductive success is one of the most inclusive measures of overall fitness, this potential response is crucial for adapting to increasing environmental temperature in natural populations.