Looks That Kill: Being Attractive Linked to Species Extinction, New Study Says
Everyone wants to be more attractive, but it turns out that species that go to extremes to attract mates may be sealing their own genetic fate.
A new study from the Center for Ecology and Conservation at the University of Exeter has found that the phenomenon of sexual dimorphism, where opposite sexes of the same species begin to develop distinctive traits apart from their sexual organs, could increase the risk of an animal's extinction, rather than ensure their survival by making them more attractive mates.
The reason, the study suggests, is that overdeveloped sexual traits (for example, a triceratops' frills and horns, or a peacock's feathers) end up making the animal a bigger target for predators.
According to the research: "The evolutionary costs of such traits help to enforce the honesty of the associated displays, but can also reduce the fitness of populations in general and thereby increase the risk of [the] population."
The study examined ancient ostracods, specifically a type of seed shrimp that existed about 84 million years ago. Of the 93 species examine (all of which went extinct), the researchers found that the males developed extremely distinct appearances, apparently causing them to overspecialize so heavily that they might have kept breeding despite their inability to deal with their environment.
This clashes with another model of sexual dimorphism, which says that sexual selection ends up breeding out harmful mutation and encouraging adaptation to one's environment.
At least in this case of the seed shrimp, this didn't seem to be the case.
According to the text of the study: "We show that species with more pronounced sexual dimorphism, indicating the highest levels of male investment in reproduction, had estimated extinction rates that were 10 times higher than those of the species with the lowest investment. These results indicate that sexual selection can be a substantial risk factor for extinction."
So, if anyone asks, tell them you now have scientific proof that looks aren't everything.