In defence of the annoying fruit fly Premium

Today, thousands of neuroscientists use fruit flies to study learning, memory, sleep, aggression, addiction and neural disorders – not to mention cancer and ageing, processes of development, the gut microbiome, stem cells, muscles and the heart.

Fruit flies can be truly annoying when they are buzzing around your living room or landing in your wine. But we have much to thank these tiny nuisances for – they revolutionised biological and medical science.

Flies and mosquitoes both belong to Diptera, the group of insects that have only two wings (from the Greek di meaning two and pteron meaning wing). However, just as most people accept the bothersome as well as the positive traits of their friends, we shouldn’t judge flies for their negative behaviour alone.

We should open our eyes to their enormous economic and environmental importance, as entomologist Erica McAlister argues in her book The Secret Life of Flies. For example, many plants (including the cacao plant that gives us chocolate) rely on Diptera as pollinators. Or try to imagine a world without flies to decompose dead animals.

I will argue from a different angle, though, to win your respect for one specific dipteran: the fruit or vinegar fly (Drosophila melanogaster).

Drosophila may be smaller than a fingernail but it can be a big nuisance in summer when it hovers over maturing fruit or emerges in swarms from litter bins. The species Drosophila was first mentioned by German entomologist Johann Meigen in 1830 and has since earned a celebrity status among scientists. It has become the best-understood animal organism on the planet and a powerhouse of modern medical research. Ten scientists working on Drosophila have been awarded a Nobel Prize in physiology or medicine.

Science’s partnership with flies started during the early 1900s when biologist Thomas Hunt Morgan at Columbia University in New York decided to test evolutionary theories, such as how genetic mutations are linked to other characteristics, and the rediscovery in 1900 of Gregor Mendel’s theories of inheritance, published 1865. Mendel remains the acknowledged father of genetics today.

Morgan was not the first to work with Drosophila. But his idea to harness the fly’s cheap husbandry (pieces of banana kept in milk bottles), and rapid reproduction (one generation in about ten days; about 100 eggs per female per day) would make it possible to study evolution in the laboratory. This is because it’s easier to see evolutionary changes in large populations of a species with high turnover.