Gustatory Acceptance, Longevity, and Utilization of Nectar and Honeydew Sugars by Anaphes iole Second International Symposium on Biological Control of Arthropods

Habitat management is a component of conservation biological control that aims to improve the availability of resources required by natural enemies. Access to non-host foods is a critical requirement for many natural enemies, and one that can be manipulated via habitat management. Food sources, usually in the form of nectar (floral or extrafloral), pollen, and honeydew supply natural enemies with energy for maintenance and reproduction. These food sources have different chemical compositions, and studies on parasitoid acceptance, survival, and longevity have helped identify the compounds most important to parasitoids, and therefore, habitat management. While pests may also exploit food sources intended for natural enemies, recent studies have shown that careful selection of food sources can reduce this possibility. Therefore, detailed knowledge of the biology of the pests and natural enemies present in the agroecosystem in question is crucial for selection of appropriate habitat management strategies. The suitability of naturally occurring carbohydrates and a commercial food source was determined for A. iole. In a gustatory response study wasps responded to all 15 of the sugars at the highest concentration tested (2 M). At this concentration, sucrose, glucose, maltose, melezitose, fructose, trehalulose, and erlose all elicited >90% acceptance. Raffinose, trehalose, mannose, galactose, melibiose, rhamnose, stachyose, and lactose led to <50% gustatory response by the wasps at 2 M. EliminadeTM a commercial food supplement, was readily accepted (92%) by A. iole. With respect to gustatory response to nectar and honeydew sugars, A. iole differs markedly from other hymenopterans that have been studied in that this parasitoid accepted all the naturally occurring sugars with which it was tested. Moreover, for many of the sugars tested, this parasitoid had lower acceptance thresholds than other hymenopterans. Wasp survival varied depending on food source and temperature. Provision with sucrose led to the greatest increase in longevity over controls. Honeydew sugars were highly variable in their effect on survival. Results from sugar digestion trials were consistent with