Antagonistic correlated responses in knockdown resistance to high temperature and chill-coma recovery after selecting for mating success at high temperature

GOMEZ F; STAZIONE L; SAMBUCETTI P; NORRY F

Buenos Aires

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

Itis known that reproductive traits such us mating success are widely affected bythermal stress. Artificial selection for thermal stress tolerance is a usefultool to evaluate thermal adaptation to warming environments. In this work weevaluated correlated responses to artificial selection in lines of Drosophila buzzatii that were successfully selected formating success at high temperature on two ecologically relevant thermotolerancetraits, knockdown resistance to high temperature (KRHT) and chill-coma recovery(CCR).. Selected lines (S lines) were generated in three replicates by allowingvirgin 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 threereplicated lines were maintained at 25 °C as control (C lines).  KRHT was measured as the time until the flieswere knocked down at 37 ° C in a glass column and CCR was measured as time untilindividuals were able to stand on their legs at 25°C after remaining placed for20 h to 0°C. Both traits were measured in flies that did not received hardeningpre-treatment as well as in flies that were heat/cold hardened respectively. Thermotolerancetraits showed significant correlated responses with higher KRHT in Sthan in C lines, both with and without a heat-hardening pre-treatment. CCR timewas longer in S than in C lines both with and without a cold-hardeningpre-treatment. Resultsshow that artificial selection affected both thermotolerance traits. KHRT andCCR showed antagonistic responses evidencing a previously observed trade‐off in Drosophila.Considering that mating success is an important fitness-related trait, correlatedresponses for its selection on  ecologicallyrelevant thermotolerance traits such us KRHT and CCR is key for adaptation to changingenvironmental temperature under the current scenario of global warming.