Meeting Abstract
P1.82 Monday, Jan. 4 Evolutionary Genetics of Heat Shock Cognate 70 in the Leafcutting Bee, Megachile apicalis (Hymenoptera: Megachilidae) MARGOTTA, J.W.*; HRANITZ, J.M.; BARTHELL, J.F.; BRUBAKER, K.D.; Bloomsburg Univ., PA; Bloomsburg Univ., PA; Univ. Central Oklahoma, Edmond; Bloomsburg Univ., PA jwm10722@huskies.bloomu.edu
Among members of a solitary bee community in the Central Valley of California, differences in nesting niche, HSP70 expression, offspring survival of abiotic stress, and geographic distribution suggest interspecific variation in thermotolerance. Two leafcutting bees, Megachile apicalis and M. rotundata, in this community display eurythermal nesting niches and differences in offspring HSP70 expression as well as survival to heat stress. Because HSP70 plays a pivotal role stress protein pathways, interspecific differences in temperature at the onset of expression and offspring survival suggest that HSP70 may function at different temperatures in each species. The goal of this project was to evaluate how interspecific variation in thermotolerance may be related to Hsc70 gene structure. We cloned and sequenced 1418 bp of the Hsc70 gene of four M. apicalis larvae and compared sequences to three other hymenopteran Hsc70 sequences (M. rotundata, Apis mellifera, and Pteromalus puparum) in a bioinformatic analysis. This analysis showed relatively small nucleotide variation between the two leafcutting bees. Interestingly, the honey bee differed substantially (139 aa substitutions, 3 deletions and 1 insertion) from the leafcutting bees and wasp at the Hsc70 gene.In M. apicalis, conserved Hsc70 gene regions contained seven protein motifs. Tajima’s D revealed stabilizing selection at 10 regions within the Hsc70 gene for M. apicalis. In contrast to honey bees, leafcutting bees may possess highly conserved (pleisomorphy) Hsc70 gene structure and function. Alternatively, comparisons with solitary bees adapted to cooler habitats may reveal the similarities between leafcutting bees and the wasp outgroup to be caused by convergent evolution in similar habitats.
