A Nutritional Profile of the Trap-Nesting Wasp Trypoxylon lactitarse (Hymenoptera: Crabronidae): Comparison of Sexes and Overwintering and Non-Overwintering Generations

Abstract

The wasp Trypoxylon lactitarse Saussure is a bivoltine trap-nesting species that possesses a non-overwintering generation (G1) and a generation that overwinters as a prepupa (G2). Thus, the nutritional needs of the G1 individuals were predicted to be different than the G2 because the latter generation needs to store energy prior to diapause. Trap-nesting Trypoxylon are also of interest because, unlike most Hymenoptera, the males guard the nest while females forage. Thus, males may lose nutrients as they stay and guard the nest. In this study, a nutritional profile was created for T. lactitarse to compare the macronutrient (protein, carbohydrates, and lipids) and micronutrient (Ca, Cu, Fe, K, Mg, Mn, Na, and Zn) levels of the different life stages of the wasp and compare individuals of the G1 and G2 generations. There were distinct changes in the nutrient levels relative to the original food source as individuals metamorphosed into larvae, pupae, and adults. G1 larvae had higher levels of carbohydrates than G2 larvae. G2 larvae had higher levels of lipids and K than G1 larvae, indicating possible differences in energy storage. In adults, there was an increase in levels of carbohydrates and Mn. Parental males, which stay and guard the nest, were found to have higher levels of carbohydrates at the end of the nesting period than females and emerging adults. One possible implication is that females may feed males during the nesting period, as the females are the only individuals to forage.