Sex-Deprived Fruit Flies Turn To Alcohol

Humans aren't the only ones who turn to alcohol for comfort. Bears, elephants, even tree shrews in the Malaysian rainforest have all been known to grab a drink or two when the time permits. A recent study shows that sex-deprived fruit flies turn to booze as well, and their behavior could help us understand human addictions better.

Half of the fruit flies were placed with female fruit flies ready to mate, while the other half was placed alongside females who had already mated and thus spurned any new advances.

"You see that the mated males actually have an aversion to the alcohol-containing food," Galit Shohat-Ophir said to Science, where her study was published. "And the rejected males have a high preference to that food with alcohol."

Shohat-Ophir originally thought that all flies would prefer the alcoholic food, but found out that sexual satisfaction played a role in determining the flies' tastes.

Neuropeptide F (NPF) is the reward chemical in a fly's brain that is released after sex. If the fly is rejected, levels of NPF drop in its brain, but come back up after the fly copes with a few drinks.

"Identifying the molecular and genetic mechanisms controlling the demand for reward in fruit flies could potentially influence our understanding of drug and alcohol abuse in humans, since previous studies have detailed similarities between signaling pathways in fruit flies and mammals," says Troy Zars, an associate professor of biological sciences at the University of Missouri and neurobiology expert.

Consuming alcohol activates reward pathways in the fly's brain and is a rather pleasurable and recreational experience for it. When sexually rejected, the flies consumed up to four times more alcohol on average.

When given NPF artificially, then the flies showed no preference for alcoholic foods, just as if they had mated.

The researchers also trained the flies to associate NPF with a particular smell, and found that flies would gravitate towards the smell just like how they would to alcohol.