Animal sex signals—communications between partners to show health and the ability to produce offspring—are key to the survival of the species.
Experts assumed these signals were naturally passed down from generation to generation, but new research shows sex signal aren’t always passed on to offspring—and can actually adaptively disappear.
“This means that certain organisms, particularly those that rely on signaling to do any mating or to tell their species apart from others, may be in more danger of extinction or hybridizing with another species if they lose signals, particularly because signal loss can happen so fast,” says Emily Weigel, a doctoral candidate with the BEACON Center for the Study of Evolution in Action at Michigan State University.
Why is signaling lost?
“In nature, it looks like signaling can still disappear, not just sometimes but often,” Weigel says. “And we don’t have a good understanding of exactly how and why it is lost in many populations.”
Studying the deficit in nature is difficult because scientists are trapped by the practical problem of having to know an animal population is already losing a signal to study its loss. They don’t get a good idea of what factor—such as population size, how genes are structured in relation to one another, and how strongly organisms respond to signals—start and influence the loss.
“We also don’t know how these factors interact, or how they change based on whether animals must signal to mate, or if it’s just an optional strategy,” Weigel says.
To conduct the study, published in the journal Ecology and Evolution, researchers evolved populations in Avida, a software environment in which self-replicating computer programs compete and evolve. Their digital populations varied in different combinations of these characteristics. They found signaling is indeed quite hard to lose in some scenarios, but not all.
How strongly the receiver prefers the signal is a huge component of whether signals are lost or not. In addition, the factor of optional or required signaling turned out to change the importance of every other factor.
“So, when we’re looking at nature, a lot of the loss might have to do with the specific pressures on an organism from its social and physical environment, and whether its biology allows for wiggle room,” Weigel says.
Outside factors can include being able to detect a mating call in a loud environment or being rendered helpless by the extra noise.
Others researchers from Michigan State and from the University of Wisconsin are coauthors of the study.
Source: Michigan State University