LIFE-HISTORY OF TRICHOGRAMMATOIDEA BACTRAE (HYMENOPTERA, TRICHOGRAMMATIDAE), AN EGG PARASITOID OF PINK-BOLLWORM (LEPIDOPTERA, GELECHIIDAE),WITH EMPHASIS ON PERFORMANCE AT HIGH-TEMPERATURES

Selected life history characteristics of Trichogrammatoidea bactrae Na garaja, a newly imported egg parasitoid of pink bollworm, Pectinophora gossypiella (Saunders), were studied at constant and fluctuating temp eratures, with emphasis on high temperatures typical of desert cotton production areas in Arizona and southern California. Developmental tim es from egg to adult ranged from 11 to just over 7 d at mean temperatu res of 22.5 and 29.5-degrees-C, respectively Development was delayed u nder fluctuating temperatures with maximums greater-than-or-equal-to 3 3.5-degrees-C. Survivorship was >90% under all but a fluctuating 25/40 -degrees-C regime. Similar results were found for Trichogramma pretios um Riley, an established species in the southwestern United States. Me an female longevity of T. bactrae adults ranged from 138 h at a consta nt 15-degrees-C to 1.5 h at 40-degrees-C. Mean fecundity peaked at 25- degrees-C (55 progeny per female), but modest fecundity (14-23 progeny per female) was maintained at temperatures from 30-35-degrees-C. The majority of eggs oviposited by newly emerged adults within the first 2 4 h of exposure to hosts were laid in the first 3 h and >90% were laid within 12 b. The 24-b rate of oviposition was a nonlinear function of female age and temperature that was maximal for 10-h-old females at a lmost-equal-to 25-degrees-C. The time of day that females of equal age were initially exposed to hosts did not significantly affect 24-h ovi position rates. T. bactrae appears well adapted to high temperatures; this environmental factor should not significantly hinder the efficacy of this biological control agent in the field.