Early-life nutrition shapes adult responses to heat and cold in Ceratitis capitata (Diptera: Tephritidae)

Abstract Early-life (immature) nutrition can shape adult physiological traits, yet its effects on thermal stress tolerance in the Mediterranean fruit fly, remain poorly understood. This study investigated how larval diet brewer’s yeast content affects adult thermal tolerance, assessed through critical thermal limits (CTmin and CTmax) and chill coma recovery time (CCRT). Larvae were reared on a gel-based artificial diet containing six brewer’s yeast levels (1.25, 2.5, 5, 12.5, 25, and 50 g), corresponding to 2.5%, 5%, 10%, 25%, 50%, and 100% of the standard diet’s brewer’s yeast content, respectively. Pupation and adult emergence were recorded, and adults were subsequently tested for thermal tolerance under controlled laboratory conditions. Pupation rates were unaffected by brewer’s yeast level, whereas higher levels significantly shortened egg-to-pupae developmental duration. Adult emergence rates also varied with brewer’s yeast level, decreasing at higher levels. Brewer’s yeast level significantly affected CTmin, with each 1% increase associated with a reduction in CTmin, indicating improved cold tolerance. In contrast, CTmax was unaffected, while CCRT increased at higher brewer’s yeast levels. Sex and its interaction with brewer’s yeast level had no significant effects on any trait. These findings demonstrate that immature nutrition can influence adult cold tolerance and recovery from chill coma, highlighting the role of developmental conditions in shaping thermal physiology. Understanding these effects may improve predictions of pest responses to climate variability and inform pest management strategies.