Temperature dependent development of the egg-larval parasitoid Chelonus oculator on the factitious host, Ephestia cautella

Development, fecundity, and longevity of the egg-larval parasitoid Chelonus oculator Panzer (Hymenoptera: Braconidae) were studied on the factitious host, Ephestia cautella (Walker) (Lepidoptera: Pyralidae) at 4 different temperatures (15 °C, 20 °C, 25 °C, and 30 °C). Developmental time from egg to adult was inversely related to temperature. Egg to adult development time ranged from 188 days at 15 °C to 28 days at 30 °C. Complete development required 489 degree-days with a developmental threshold of 12.5 °C. Adult male and female longevity ranged from 43 days at 20 °C to 17 days at 30 °C. Maximum production of offspring per female (2626 ± 152) was obtained at 25 °C. Sex ratios were female-biased at 15 °C (0.8♂:1♀), but were increasingly male-biased at higher temperatures to a maximum of 4.4♂:1♀ at 30 °C. The highest net reproductive rate was 168.7 at 25 °C, whereas the highest intrinsic rate of increase and the shortest doubling time occurred at 30 °C.