How to cope with rejection...the love life of a fruit fly.
Ever noticed those fruit flies buzzing around your overly ripe bananas? Only a couple of millimetres long, these tiny flies are attracted to rotting, fermenting fruit for food and a place to lay their eggs. Small, rapidly reproducing with a short life span, this humble fly is a geneticist’s dream.
In our Love Island episode, we mentioned a project which investigated the human brain’s reward systems. The researchers found that male fruit fly who were rejected by females drank four times as much alcohol as those who had sex. Never mind the love life of the fruit fly, why did the researchers use them to investigate the human brain?
Why are fruit flies used in so many research projects? Researchers use the common fruit fly (Drosophila melanogaster) as a genetic model for several human diseases, including Parkinson’s and Alzheimer’s disease, as well as a way to study the mechanisms of drug addiction. They are one of the most studied species on the planet, used in many different research projects, from wound repair and infection prevention, to cognitive development and memory. The common fruit fly shares 60% of its genome with humans, this means they can be used to study the relationship between natural and drug rewards in the body.
So what about the love life of a fruit fly? It turns out male fruit fly have a sexy courtship routine to try and attract females, including a song made by vibrating their wings. Females become receptive about 8-12 hours after they have emerged, but can reject males by moving away or kicking them.
What did the research find? Male fruit fly who were deprived of sex, chose food containing a higher percentage of ethanol. This happened because of the levels of a neuropeptide in the body; mating increased and sexual deprivation reduced the levels of this neuropeptide. This meant they reached the same level of ‘high’ after drinking the alcohol, as they would have done after sex. It turns out rejected fruit fly turn to alcohol as a substitute to sex, maybe they are more like humans than we think.