Gustatory response by the hymenopteran parasitoid Cotesia glomerata to a range of nectar and honeydew sugars

The feeding response of food-deprived Cotesia glomerata to solutions of 14 naturally occurring sugars was determined. Glucose, fructose, sucrose, maltose, erlose, melezitose, trehalose, and stachyose all elicited a feeding response. The sugars differed, however, with respect to the lowest concentration at which they were accepted (acceptance threshold). The parasitoids showed no feeding response when presented with 2 M solutions of galactose, mannose, rhamnose, lactose, raffinose, and melibiose. Sugars from the latter group did not show a deterrent effect when offered to water-deprived parasitoids. When mannose, rhamnose, melibiose, or raffinose were combined with low molar solutions of either fructose or sucrose, sucrose acceptance was affected by mannose and raffinose, whereas no negative interactions were found in mixtures with fructose. Compared to acceptance thresholds reported in other insect systems, the responses of C. glomerata differ considerably with respect to both the range of saccharides accepted as well as the acceptance thresholds. The novel finding that the parasitoid accepts a number of sugars that fail to elicit a feeding response in its herbivorous hosts is of particular interest to the use of (selective) food supplements in biological control programs.[PUBLICATION ABSTRACT]