Anupama Dahanukar and her team from the University of California, Riverside, examined the feeding preference of the common fruit fly for beer and other products of yeast fermentation.They found that a receptor, a protein that serves as a gatekeeper, which is associated with neurons located in the fly''s mouth-parts is instrumental in signalling a good taste for beer.“Insects use their taste system to glean important information about the quality and nutritive value of food sources,” Dahanukar said.“Sugars signal high nutritive value to flies, but little is known about which chemical cues flies use for food sources that are low in sugar content – such as beer,” she said.The receptor in question is Gr64e, and once a fly has settled on beer, the receptor detects glycerol and transmits this information to the fly’s neurons, which then influences the fly’s behavioural response.She also said that flies use other receptors in their sensory organs to find food from a distance.“Taste becomes important only after the fly makes physical contact with food.“A fly first locates food sources using its odour receptors – crucial for its long-range attraction to food. Then, after landing on food, the fly uses its taste system to sample the food for suitability in terms of nutrition and toxicity,” she added.The study has been published online in Nature Neuroscience.