Meeting Abstract
P3.90 Monday, Jan. 6 15:30 Effect of Cooling Rate on the Rapid Cold Hardening Response in Drosophila melanogaster ELLER, OC*; EGGE, AR; MORGAN, TJ; Kansas State University; Kansas State University; Kansas State University oceller@ksu.edu
Climate is a significant environmental factor that influences the distribution and abundance of most organisms on Earth. One constantly changing component of climate is temperature and we are interested in how organisms respond to stress brought on by temperature fluctuations coupled with cold stress. Drosophila melanogaster is a cosmopolitan species that inhabits many different environments throughout the world and exhibits a wide-range of physiological thermal adaptations. Rapid cold hardening (RCH) is a short-term acclimation response in which an organism is exposed to a non-lethal cold temperature before being exposed to an extreme cold temperature. This non-lethal pretreatment improves cold survival for individuals that have the ability to acclimate over a short period of time. Previous experiments investigating the RCH response have directly transferred flies from rearing temperature to pretreatment to extreme cold exposure. These direct shifts do not translate to natural conditions where organisms are gradually exposed to new temperatures. Our goal was to compare experimental environments of a more natural context to see if or how the RCH response changed in relation to direct transfer experiments. We used thermal ramping to cool the experimental environment at two ecologically natural but different rates and then compared survivorship after an extreme cold shock between flies that received a ramping pretreatment and flies that received a direct transfer pretreatment. Our results indicate that neither the speed of cooling nor direct transfer pretreatment have a significant effect on an individual’s ability to acclimate and survive extreme cold temperatures. These results are significant as they demonstrate that direct and ramping RCH pretreatments are both ecologically relevant measures of thermal performance.
