Annalee Newitz writes on io9.com:
It’s a classic tale of how mediocrity is maintained. Evolutionary biologists in California have discovered that when males shower attractive females with attention, it actually undermines those females’ fitness as mothers. That means fit females don’t pass their genes on.
Today PLoS Biology published a study of fruit flies, a species where the male flies show a marked preference for mating with larger females because they are more fecund. The problem is that the males show such aggressive preferences that they basically badger the females constantly to mate. What this means is that the females are so harried that they have less time to search for food, which degrades their health. Also, among fruit flies, the mating process is itself damaging to the health of the females — fruit fly sperm is toxic.
As a result, the most-desired females become far less capable of generating healthy offspring. And the smaller, less fit females wind up bearing as many offspring as the fitter ones. In the end, the males’ aggressive mating with the fittest females ends up preventing their species from evolving into a much fitter group.
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