DEVELOPMENTAL RATE AS A FUNCTION OF TEMPERATURE IN NORTHERN CORN-ROOTWORM (COLEOPTERA, CHRYSOMELIDAE)

Development of immature northern corn rootworm, Diabrotica barberi Smi th & Lawrence, was studied at 7 constant temperatures ranging from 15 to 31.5 degrees C. Development occurred at all temperatures, however, survival was lowest at 15 and 31.5 degrees C for both males and female s. The proportion of time spent in each life stage from hatch to adult emergence was independent of sex and approximate to 15% for Ist insta rs, 18% for 2nd instars, 41% for 3rd instars, and 25% for the pupal st age. Developmental times, from hatch to adult emergence, between males and females were substantially different. A developmental threshold o f 10.2 degrees C was estimated for development from hatch to adult eme rgence. Development from hatch to adult emergence was fastest al 30 de grees C, taking approximate to 28 d, and slowest at 15 degrees C takin g 98 d.