Submitted to: Great Lakes Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/1996
Publication Date: N/A
Interpretive Summary: Temperature is an important environmental variable that strongly influences the biology and population ecology of insects. We studied one native aphid parasite and two exotic Russian wheat aphid parasite species to determine how temperature fluctuations that might be encountered in the field in the Great Plains would affect the time required to develop from birth to adulthood. Results suggest that the two exotic parasites are adapted to th climate of the Southern Great Plains, at least with respect to the influence of temperature on immature development. Furthermore, the parasites' developmental response to temperature was similar to that of their aphid hosts, including the Russian wheat aphid, suggesting that developmental response to temperature will not limit the effectiveness of the parasites in biological control.
Technical Abstract: Temperature is an important variable influencing the biology and ecology of insects. Poor adaption to climate may reduce the effectiveness of parasitic insects in biological control. Native and Syrian Diaeretiella rapae (M'Intosh) and Argentinean Aphidius colemani Viereck were reared in growth chambers in three fluctuating temperature regimes with average daily temperatures of 12, 18, and 24 deg C. Estimates of temperature thresholds for immature development were 3.3, 3.5, and 2.8 deg C, for Oklahoma D. rapae, Syrian D. rapae, A. colemani, respectively. Estimates of thermal requirements for development from egg to adult were 297, 278, and 301 degree-days for the three parasitoids. Dry weights of adults reared in different fluctuating temperature regimes did not differ significantly among sexes, but adults from regimes with average temperatures of 12 and 18 deg C had significantly greater weights than those reared in a regime with an average temperature of 24 deg C. Results suggest that developmental response to temperature will not limit the effectiveness of the parasites in biological control.