Enterobacter-based dietary supplements in both larvae and adult diet affect thermal response of sterile males

Thermal stress can affect the field performance of sterile males used in the sterile insect technique (SIT). We tested whether adding autoclaved Enterobacter as a dietary supplement improves thermal tolerance in sterile Vienna 8 genetic sexing strain males of Ceratitis capitata. Larval and adult diets were supplemented with autoclaved Enterobacter, and critical thermal limits - critical thermal minimum (CTmin), critical thermal maximum (CTmax), and chill-coma recovery time (CCRT) - were measured. Enterobacter supplementation affected neither CTmin nor CTmax. In contrast, CCRT was strongly influenced by larval diet: sterile males reared on the standard diet recovered faster than those reared on the Enterobacter-supplemented diet. Wild males showed a lower CTmax but a much faster CCRT than sterile males. Overall, Enterobacter supplementation did not improve thermal limits but affected chill-coma recovery, highlighting the importance of characterising the thermal profile of sterile males before release and the complex interplay between food quality, physiology, and mass-rearing in the successful application of SIT.