By generating starvation- resistant flies through experimental evolution, these researchers at UNLV were able to more closely observe the relationships between sleep behavior, feeding, foraging, and starvation resistance. Because sleep and feeding are related to metabolic rates, they could potentially contribute to Drosophila melanogaster resistance under starvation conditions. The flies used in this experiment have been bred over 60 generations in order to become starvation resistant. These flies were bred on an agar diet that was devoid of calories, and live around 18 days when under starvation conditions. Flies that have not been selected for starvation resistance survive around 2-3 days.
Through studying these starvation resistant flies, researchers found that these experimentally evolved flies were higher in body fat than their counterparts. It was found that this bodyweight increase occurred during larval development. Adult starvation resistant flies were found to have a reduced food intake, as well as longer sleep duration compared to normal flies. This longer sleep duration potentially results in energy conservation. An important variable in these experiments is Drosophila energy stores. Starvation selected flies have elevated energy stores, and this may affect the relationships between these traits. By selecting the food intake at certain stages in normal flies, and flies bred for starvation resistance, this variable was accounted for. A difference in traits between the two groups was still observed. This suggested that their findings are due to genetic differences, and not the higher energy stores in starvation flies.