Submitted to: Biological Control Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: July 20, 2005
Publication Date: September 20, 2005
Citation: Williams Iii, L.H., Roane, T.M., Beach, J.P. 2005. Gustatory acceptance, longevity, and utilization of nectar and honeydew sugars by anaphes iole, an egg parasitoid of lygus bugs. Biological Control Symposium Proceedings. Interpretive Summary: Plant bugs are serious pests of many crops, including cotton and soybean, in the United States. Beneficial insects are useful in killing plant bugs, but require additional food sources to maximize their potential. Food sources, such as nectar, supply beneficial insects with energy for flight and reproduction. Thus, a better understanding of the nutritional requirements of beneficial insects has important implications for plant bug control. We conducted experiments to evaluate the suitability of naturally occurring sugars and a commercial food source for a beneficial insect that attacks plant bugs. Our results indicate that the insect fed on all 15 of the sugars at the highest concentration tested. At this concentration, sucrose, glucose, maltose, melezitose, fructose, trehalulose, and erlose resulted in the strongest feeding response. Eliminade™, a commercial food supplement, was also readily accepted by the insect. The effect of sugar on the insect’s lifespan varied depending on food source and temperature during the experiment. Provision with sucrose led to the greatest increase in lifespan. Results from sugar digestion trials were consistent with those from feeding acceptance and lifespan trials, and suggested the presence of several digestive enzymes in the alimentary canal of the insect. The broad and sensitive range of feeding, coupled with enhanced longevity afforded by some sugars, might be helpful in the development of a food source for the beneficial insect that is not exploited by plant bugs.
Technical Abstract: Food sources, such as nectar and honeydew, supply natural enemies with energy for maintenance and reproduction. These foods are a critical requirement for many natural enemies, and can be manipulated via habitat management. Recent studies have shown that careful selection of food sources can reduce the likelihood of exploitation of these foods sources by pests. Detailed knowledge of the nutritional ecology of natural enemies and pests is crucial for selection of appropriate habitat management strategies. We evaluated the suitability of naturally occurring carbohydrates and a commercial food source 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. Eliminade™, a commercial food supplement, was readily accepted (92%) by A. iole. 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 those from gustatory discrimination and longevity trials, and suggested the presence of invertase in A. iole guts. The broad and sensitive range of gustatory perception, coupled with enhanced longevity afforded by some sugars, might be helpful in the development of a food source for A. iole that is not exploited by Lygus.