Agencia SINC – Fear Can Model Populations and Foster Evolution. This is what happens with a species of rodent living in Western Europe and North Asia: the red vole (Myodes glareolus). When these rodents feel threatened by a predator, they produce more offspring .

The team of biologists from Finland and the Countries -Bas has studied the chemical reactions of these small mammals to understand their behavior. The results reveal, for example, that women exposed to predation produce litters whose offspring are 50% more numerous than mothers in safety.

"The most surprising thing about this study is that the cause The change in digital reproduction has been indirect," said Marko Haapakoski, postdoctoral researcher at Jyväskylä University in Finland. that the chemical signal of the predators – without the active presence of these – was sufficient to increase the offspring.

The smell also scares

Predators can also scare the dams up to They are hiding without being devoured. "Our study shows that the resulting fear alters the behavior and reproduction of these prey," says Kevin Matson of the Wageningen University in the Netherlands.

This book shows that a frightening experience like this one.It can be communicated to individuals of the same population, even when they have not seen, felt or heard the predator themselves. To reach these conclusions, The scientists conducted an experiment.

"When a separate group of male voleen-red males were exposed to a weasel, they produced chemical messages that could be detected and interpreted by the voles of our study," says Alwin. Hardenbol, lead author of the research and scientist at the Dutch University.

Females, if they felt that their chances of being eaten were large, produced more offspring, since might be their last litter . According to biologists, simple physiological mechanisms allow mothers to adjust the size of their litters.

"Until now, it has been suggested that highly fertile species such as voles react to high predation by offsetting reproduction," Danielle Lee, Ecologist, Southern Illinois University (USA) , who did not participate in these works. "This field study confirms that these responses are mediated by chemo-wave signals," he concludes.