Meeting Abstract
Survival of the Antarctic midge, Belgica antarctica, on the terrestrial habitats of the Antarctic Peninsula is promoted, not only by the adaptation to tolerate prolonged exposures, but also by their ability to respond to unpredictable changes in their environments. Rapid cold-hardening (RCH) describes the extremely swift acclimatory response of insect that occurs within minutes to hours. Most traditionally, the RCH response is induced by a brief exposure to mildly-low temperatures. However, a similar rapid acclimatory response can also be elicited by an exposure to drought. In this study, we characterized this drought-induced RCH response in larval B. antarctica. Compared to fully hydrated larvae, those desiccated at various relative humidity (R.H.) conditions for 2 h had a significantly greater survival to freezing at -14 °C by ~50%. Although the amount of water larvae lost varied between 4%-16%, all treatments were equally effective in eliciting the protective response against freezing stress, and its induction was evident within 30 min of desiccation at 85 or 0% R.H. conditions. Interestingly, the RCH protection induced by desiccation persisted after larvae were allowed to recover a significant portion of the lost water. Our results indicate that larval B. antarctica are highly sensitive to desiccation stress, capable of swiftly initiating physiological changes in response to a small reduction in their body water content. Supported by NSF grants PLP-1341385 and PLP-1341393.
