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 degrees C, 20 degrees C, 25 degrees C, and 30 degrees C). Developmental time from egg to adult was inversely related to temperature. Egg to adult development time ranged from 188 days at 15 degrees C to 28 days at 30 degrees C. Complete development required 489 degree-days with a developmental threshold of 12.5 degrees C. Adult male and female longevity ranged from 43 days at 20 degrees C to 17 days at 30 degrees C. Maximum production of offspring per female (2626 +/- 152) was obtained at 25 degrees C. Sex ratios were female-biased at 15 degrees C (0.8 male:1 female), but were increasingly male-biased at higher temperatures to a maximum of 4.4 male:1 female at 30 degrees C. The highest net reproductive rate was 168.7 at 25 degrees C, whereas the highest intrinsic rate of increase and the shortest doubling time occurred at 30 degrees C.