Sex-Starved Fruit Flies Turn to Drink
Male fruit flies that have been rejected by females drink significantly more alcohol than those that have mated freely, scientists say.
In an article in Science, researchers suggest that alcohol stimulates the flies’ brains as a “reward” in a similar way to sexual conquest.
The work points to a brain chemical called neuropeptide F, which seems to be regulated by the flies’ behaviour.
Human brains have a similar chemical, which may react in a similar way.
The connection between alcohol and this chemical, which in humans is known as neuropeptide Y, has already been noted in studies involving hard-drinking mice.
The new work explores the link between such reward-seeking and the study of social interactions, said the lead author of the report Galit Shohat-Ophir, now of the Howard Hughes Medical Institute in Virginia, US.
“It is thought that reward systems evolved to reinforce behaviours that are important for the survival of both individuals and species, like food consumption and mating,” Dr Shohat-Ophir told BBC News.
“Drugs of abuse kind of hijack the same neural pathways used by natural rewards, so we wanted to use alcohol - which is an extreme example of a compound that can affect the reward system - to get into the mechanism of what makes social interaction rewarding for animals.”
Working in the laboratory of Ulrike Heberlein at the University of California, San Francisco, Dr Shohat-Ophir and colleagues subjected a number of flies to a wide variety of fates.
In one set of experiments, male flies were put in a box with five virgin females, which were receptive to the males’ advances. In another, males were locked up with females that had already mated and which thus roundly rejected the males’ attempts at sex.
Offered either their normal food slurry or a version charged with 15% alcohol, the mated males avoided the alcohol, whereas the sexually deprived males went on a comparative bender