Meeting Abstract

P1.10  Tuesday, Jan. 4  Dried eggs: consequences of plant microclimate for Manduca sexta embryos POTTER, K.A.*; WILSON, K.; WOODS, H.A.; Univeristy of Montana, Missoula; Univeristy of Montana, Missoula; Univeristy of Montana, Missoula kap15@cornell.edu

A primary physiological challenge for terrestrial insects is to conserve sufficient water. This challenge is exacerbated during the egg stage because eggs have large surface:volume ratios and most are laid with finite supplies of water. Our research focuses on how egg physiology and leaf microclimates interact across mesic-xeric gradients. Eggs laid on plants experience microclimates that can vary considerably from the surrounding air. Using the model insect Manduca sexta we are examining (1) how leaf microclimate affects embryo performance and (2) how eggs have evolved to cope with variable environmental aridity. At our primary field site in the Chihuahuan Desert, both of M. sexta’s host plants, and particularly Proboscidea parviflora, provide relatively cool, moist microclimates for eggs [also see companion poster by K. Wilson]. Preliminary results suggest that eggs of desert M. sexta are robust to desiccation, whereas eggs from more mesic populations are more susceptible to desiccation stress. A combination of host plant buffering plus adaptations in egg traits (e.g., percent water content) helps embryos cope with variable risks of desiccation across environments.