Thermal resilience may shape population abundance of two sympatric congeneric Cotesia species (Hymenoptera: Braconidae)

Basal and plasticity of thermal tolerance determine abundance, biogeographical patterns and activity of insects over spatial and temporal scales. For coexisting stemborer parasitoids, offering synergistic impact to the efficacy of biological control, mismatches in thermal tolerance may influence their ultimate impact in biocontrol programs under climate variability. Using laboratory-reared congeneric parasitoid species Cotesia sesamiae and Cotesia flavipes Cameron (Hymenoptera: Braconidae), we examined basal thermal tolerance to understand potential impact of climate variability on their survival and limits to activity. We measured upper- and lower -lethal temperatures (ULTs and LLTs), critical thermal limits [CTLs] (CTmin and CTmax), supercooling points (SCPs), chill-coma recovery time (CCRT) and heat knock-down time (HKDT) of adults. Results showed LLTs ranging -5 to 5°C and -15 to -1°C whilst ULTs ranged 35 to 42°C and 37 to 44°C for C. sesamiae and C. flavipes respectively. Cotesia ...