Fruit flies fear lion feces

May 30, 2018, Lund University
Fruit fly (Drosophila melanogaster). Credit: Marcus Stensmyr

A new doctoral thesis from Lund University in Sweden shows how fruit flies use their sense of smell and humidity to find food, avoid dehydration and discover the best place to lay their eggs—in overripe marula fruits. Faeces from herbivores are also suitable, but the flies reject carnivore excrement.

Summer is high season for tiny (Drosophila melanogaster). Overripe fruit is their favourite haunt, and if the fruit is in a relatively humid location, the fruit flies like it even more.

On Friday 1 June, Suzan Mansourian will publicly defend her thesis Drosophila sensory neuroethology, in which she examined fruit fly behaviour and the nerves and neural pathways that govern this seemingly simple organism. Together with colleagues, Suzan Mansourian investigated and mapped the receptors on the fruit fly's antennae, which it uses to locate food, humidity, reproductive partners, and a good place to lay its eggs. Some receptors detect fragrance molecules from the fermentation process in rotting fruit—a fragrance that signifies food for the fruit fly.

Other receptors react to the smell of phenol, which is released by the pathogenic bacteria in the excrement of predators. When the fruit fly identifies the smell of phenol, it avoids laying its eggs in the location, as it is a dangerous place for the larvae. Mansourian made the discovery in connection with fieldwork in Africa. Her results show that fruit flies shun the excrement of lions, but have no objections to laying their eggs in giraffe faeces.

In her thesis, she also describes the fruit fly's humidity receptors, located behind the antennae. These receptors function like a sixth sense for the fruit fly, helping it to find environments where it can avoid dehydration. These humidity enable the fruit fly to find its way into kitchens, for example, where the humidity in the air is usually relatively high, around 70 per cent.

Although the fruit fly is a generalist and manages to survive well in widely diverse environments, Suzan Mansourian reveals that it thrives best of all in the vicinity of overripe marula fruits, which are plentiful for parts of the year in the whole of southern Africa. Her conclusion is that marula is the original host plant of the fruit fly.

The findings in the thesis increase knowledge of the fly's senses of smell and , as well as their underlying mechanisms.

"These results could lead to new approaches and strategies in combating mosquitoes and insect pests", says Suzan Mansourian.

Explore further: Freeloading orchid relies on mushrooms above and below ground

Related Stories

How to kill fruit flies, according to a scientist

August 9, 2017

As a researcher who works on fruit flies, I often get asked how to get them out of someone's kitchen. This happens to fly researchers often enough that we sit around fly conferences (these actually exist) and complain about ...

Researchers discover fruit fly aphrodisiac

September 29, 2011

(PhysOrg.com) -- People, mostly of the male persuasion, have been searching the world for a true aphrodisiac for pretty much all of recorded history, unfortunately, the search has been mostly fruitless, which makes this latest ...

Behavioral biology: Ripeness is all

March 10, 2017

In contrast to other members of the Drosophila family, the spotted-wing fly D. suzukii deposits its eggs in ripe fruits. Biologists from Ludwig-Maximilians-Universitaet (LMU) in Munich have now elucidated the sensory basis ...

Recommended for you

Researchers capture 'key' to deadly malaria infection

December 13, 2018

An international team led by Institute researchers has visualised the unique molecular 'key' used by the world's deadliest malaria parasite, Plasmodium falciparum, to enter and infect human blood cells.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.