The critical impact of sub- and supra-optimal temperatures on male fertility potential of an invasive fruit fly

This study investigates the impact of temperature on male fertility in the
invasive pest Drosophila suzukii, focusing on both developmental and
post-emergence temperature effects. We exposed flies to 11 temperatures
(10-30°C) over varying durations, revealing asymmetrical thermal
performance curves. Developmental temperatures between 9.8–29°C and adult
temperatures between 10.05–34.8°C defined fertility limits (TFmin and
TFmax). Males exposed to sub- or supra-optimal temperatures were sterile
at emergence, with sterility persisting across life stages. Supra-optimal
temperatures in adults induced sterility within days, while sub-optimal
temperatures at adulthood prevented fertility. Cold-acclimated males, in
reproductive quiescence, progressively regained fertility when transferred
to 20°C, showing anatomical recovery but reduced mating attractiveness.
This study defines male sterility thermal limits and highlights the
partial fertility recovery in cold-acclimated males, providing insights
into D. suzukii population dynamics after winter.