Tiny vinegar flies fall in love with feces

So fall in love with small flies
In the world of flies, faeces are not only an excrement product but also a means to fall in love. Do vinegar flies settle on overripe fruit, but they take off small kothaufen. With this, they draw attention to their conspecifics. This is what scientists from the Max Planck Institute for Chemical Ecology in Jena found out.

For the study, various experiments were carried out with two to five-day-old vinegar flies (Drosophila melanogaster). Among other things, the scientists recorded traps of various fragrances and counted the flies baited in this way. In another experiment, they determined how attractive or deterrent a scent is. In addition, individual animals were placed in a glass tube into which various gases were introduced.

Small Kotballen let the mini-flying lie to attract attention. Image: Stefan Redel - fotolia

A fragrance was considered attractive when the fly moved against the wind, ie in the direction of the scent source. With the help of a chemical analysis, the scientists investigated the question of which substances in the feces are so attractive to the flies.

Essigfliegen find food sources through the scent of overripe fruits
The fruit is not only for food intake, but is also a place of dating and egg laying after mating. The evaluation of the data has shown that feces are an important communication tool. The excretions contain sexual fragrances that vary depending on the type and gender.

The volatile substances attract conspecifics, as the test in the glass tube confirmed: The flies went with scents from their feces always in the direction of fragrance source. Even the smallest amounts increase the attractiveness of the fruits drastically. At the same time, the flies eat more food, if the fruit can be found kuchenäufchen.

If especially many flies visit a fruit, more eggs are also deposited. The hatching fly larvae can benefit from the presence of other larvae. Presumably, it facilitates food intake, if the fruits are already "pre-digested" by microorganisms in the feces. This will be clarified by future studies. Furthermore, it would be interesting to see if the odor that needs getting used to influenced the mate choice, the courtship behavior and the oviposition of the flies. It remains unclear whether the results are transferable to related species such as the cherry vinegar fly. This important pest in fruit and viticulture mainly affects young fruits. (Sb)