All creatures have a hierarchy of needs, and at the top of the list are food and the drive to reproduce. And new research shows that once a male fruit fly has a full stomach, it starts to get other ideas.
A hormone molecule called DH-31 surely determined whether any fruit flies were celebrating Valentine's Day on Monday. We know this, thanks to a neurobiology professor at UC San Diego named Jing Wang, who has published his research in the journal Nature.
The molecule is carried from the gut to the brain, where it activates two neural circuits. One of them tells the fly to stop feeding.
“And the other circuit is to initiate courtship, and this hormone basically tells the fruit fly that now you have something else to do,” said Wang.
DH-31 is most easily produced when male flies eat a high-protein meal from rotting fruit. Wang said the next step, courtship, is made up of many familiar behaviors, including song.
“The male fly will perform a courtship song to entice the female to be receptive to the male’s courtship approach,” Wang said. “And if the female fly is in the right mood, the female fly will stop and the male fly will go through the next step of courtship behavior, including copulation.”
A female fruit fly will have several of these encounters, producing as many as 200 fertilized eggs during her two-week life span. Jing Wang’s research may be the first to show a direct neural relationship between eating and mating. Humans don’t have a DH-31 hormone, as far as we know. But Wang said the tiny bodies of fruit flies are not too different from ours.
“Therefore we can get a lot of insight into how the nervous system works. And some of which we can extrapolate to human systems,” he said.
For people, we know there are some foods, like oysters, that are considered to be aphrodisiacs. Such notions are little more than folk tales. But we know scientifically that a good meal has a very positive effect on love among fruit flies.
