The Evolution of Drosophila melanogaster as a Model for Alcohol Research In this paper, researchers investigate the relationship between ethanol and Drosophila in an ecological and evolutionary perspective. Fruit flies have many adaptations due to a prevalence of ethanol in their environment. Typically fruit flies are found near ripe food which can hold up to 5% ethanol. Flies metabolize ethanol and use it as an energy source. Fruit flies also contain a smaller version of Alcohol Dehydrogenase (ADH) which differs slightly from the longer vertebrate version of the protein, indicating that fruit flies had an earlier ecological change to ethanol in ripe fruit. ADH is also necessary for survival on ethanol foods. Researchers found that having ethanol as the only source of calories induced a longer survival rate indicating that ethanol is a strong source of calories for Drosophila. Behavioral studies of Drosophila have shown that fruit flies with a longer and stronger exposure to ethanol ...