Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2001
Publication Date: 10/15/2002
Citation: MENON,A., FLINN,P.W., DOVER,B.A., INFLUENCE OF TEMPERATURE ON THE FUNCTIONAL RESPONSE OF ANISOPTEROMALUS CALANDRAE (PTEROMALIDAE: HYMENOPTERA), A PARASITOID OF THE LESSER GRAIN BORER, RHYZOPERTHA DOMINICA (BOSTRICHIDAE: COLEOPTERA), JOURNAL OF STORED PRODUCTS RESEARCH 38: 463-469. 2002. Interpretive Summary: There is increasing concern over the adverse environmental and health risks of conventional chemical control in stored grain. This has resulted in greater interest in the use of biological control of stored grain insects. Laboratory studies were conducted to assess the effectiveness of the parasitoid wasp, Anisopteromalus calandrae for controlling lesser grain borer in wheat over a range of grain temperatures. Grain temperature is important, because other beneficial insects are often less efficient at low temperatures. We found that the parasitic wasps were most effective at 30 and 35 C. The wasps parasitized very few beetle larvae at 20 C. This research demonstrated that biological control using this parasitic wasp is more effective at grain temperatures ranging from 30 to 35 C. This species of parasitic wasps is often found naturally in grain stores, and grain is often stored at 30-35 C. The ability of A. calandrae to parasitize the lesser grain borer over a range of grain temperatures at which wheat is most likely to be stored during the summer makes it an excellent candidate for natural control.
Technical Abstract: The functional response of Anisopteromalus calandrae (Howard) parasitizing 4th instar Rhyzopertha dominica (Fabricius) on wheat was estimated over a range of temperatures and host densities. A functional response equation was used where a quadratic component that included temperature was substituted or handling time. The instantaneous search rate was found to increase with temperature. The maximum rate of parasitization was 13 larvae/24h period at 30 C and 35 C. Handling time was lowest at 30 C and highest at 20 C. Results from this study could be incorporated into existing expert systems for pest management in stored grain.