Delete that Tinder app, plover birds. A new study says that promiscuity can sometimes slow down the evolution of your species (if you’re a shorebird, that is).
You might assume that promiscuity is a good thing from an evolutionary perspective. In theory, more sex could mean more rapid diversification and genetic diversity, which means a species might be more likely to adapt to an environment and form a new species. However, new research led by the University of Bath’s Milner Centre for Evolution says that’s not the case.
“We’re very excited about these findings as this theory completely overturns conventional wisdom,” professor Tamás Székely, from the University of Bath’s Milner Centre for Evolution, said in a statement.
In a study published in the journal Evolution, they put forward evidence to say that certain species might be held back by their polygamous behavior.
They analyzed the genetic structure of 79 populations of 10 different species of plover, a shorebird, from across the world. Plovers are an interesting choice to study when it comes to different mating systems, as six of the species they studied were monogamous and the other four were polygamous.
Their findings showed significantly fewer subspecies for polygamous species than for monogamous species. Polygamous species were also shown to have notably less genetic structure than their monogamous cousins.
The team behind the study said this is most likely because polygamous behavior can dilute genetic differences across geographic areas. If a species is monogamous, then their offspring will remain more genetically distinct compared to the offspring whose parents have spread their genes among many other partners. This means that they would be more prepared to “drift off” and form a new species through a process of speciation, as their genetic differences are more concentrated.
As lead author Josie D’Urban Jackson explains: “Our findings suggest that because of the pressure to find more than one mate, polygamous shorebirds may search large areas and therefore spread their genes as they go. This means they effectively mix up the gene pool by diluting any genetic differences between geographically distant locations, so that populations are less likely to diversify into new species over time.”
“In contrast, monogamous species only have to find one partner to pair with each season and tend to come back to the same breeding sites over time. This means they can gradually adapt to their local environment which increases the chance that they will split off and form a new species.”