Wednesday, 20 November 2002 - 1:24 PM
1075

This presentation is part of : Ten-Minute Papers, Section B. Physiology, Biochemistry, Toxicology, and Molecular Biology

Life cycle oxygen consumption in the managed pollinators Megachile rotundata and Osmia lignaria

William P. Kemp, USDA ARS, Bee Biology & Systematics Laboratory, 5310 Old Main Hill, Utah State University, Logan, UT, Jordi Bosch, Utah State University, Department of Biology, Logan, UT, and Brian Dennis, University of Idaho, Department of Fisheries & Wildlife, College of Forestry, Wildlife, and Range Sciences, Moscow, ID.

We studied the oxygen consumption of two megachilid bees (Hymenoptera: Megachilidae), Megachile rotundata (F.) and Osmia lignaria Say, at selected, biologically-relevant intervals throughout their respective lifecycles. The U-shaped oxygen consumption curve and the static weights of wintering (non-feeding) prepupae that we observed for M. rotundata support previous arguments for a winter diapause similar to that observed in other Hymenoptera. For O. lignaria, which overwinters as an adult, we found increasing oxygen consumption temperature sensitivity and continuous weight loss throughout the wintering period. However, our observations on adult O. lignaria wintering requirements are consistent with the previously published results of for overwintering M. rotundata prepupae, and reveal sharply increasing survival rates for both species when wintered for a minimum of three mo. In spite of the observed trends in temperature sensitivity of wintering O. lignaria, we interpret the greatly reduced survival in both M. rotundata and O. lignaria, as an indication that a critical biological process, diapause, is disrupted among individuals wintered for less than three mo. In the continued development of these two species as commercial scale pollinators on an ever-increasing list of target crops, any similarities or contrasts observed between the “summer bee,” M. rotundata, and the “spring bee,” O. lignaria, while being of interest from a biological perspective, will likely have important implications in the continued development of sustainable population management protocols.

Species 1: Hymenoptera Megachilidae Megachile rotundata (alfalfa leafcutting bee)
Species 2: Hymenoptera Megachilidae Osmia lignaria (blue orchard bee)
Keywords: diapause, wintering

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