A decades-old theory that claimed males are genetically wired to be promiscuous while females are naturally more choosy is being disputed by a researcher at UCLA who claims the original study was flawed and should never have been published.
Angus John Bateman's 1948 study involved placing six fruit flies (three of each gender) with visibly large mutations, such as curly wings or thick bristles, in a jar, reports Science News. When the fruit flies mated and multiplied, he was then able to determine how many had been parented by which fly, based on the progeny's inherited mutations. He concluded "males produced many more offspring from multiple mates while females produced the same number of adult children whether with one mate or many," reports the Daily Mail.
But Patricia Adair Gowaty, a professor of ecology and evolutionary biology at UCLA, recreated the experiment with modern, DNA-analysis technology and found that flies with two large mutations were less likely to survive, thereby skewing the results of the experiment since not all offspring were accounted for.
She concluded by saying the original theory — one that has been cited in more than 2,000 papers over the years — is inherently flawed. In fact, her report found that females can be just as promiscuous as their male counterparts.
But not everyone is convinced of Gowaty's challenge to evolutionary biology theory.
"Bateman's theory can not be incorrect. Males are promiscuous," says Rama Singh, a biology professor at McMaster University whose book, Rapidly Evolving Genes and Genetic Systems, debuts on Canadian shelves next week.
Singh maintains that while Bateman's experimental design of using mutations with large effects may have been flawed, the conclusions he came to are accurate.
"His conclusion that males are promiscuous is an everyday phenomenon," says Singh. "It's not something one has to prove. Sometimes science does experiments to prove what is common sense. It is common sense in most organisms, especially … insects, mammals, that males are continuously trying to mate."
Singh says his own research takes the theory a step further by arguing that not only are males more promiscuous than females, they are always actively trying to mate. He says males will court, manoeuvre, fight off other males — whatever is necessary to win the female.
"The male's heightened sexual activity was noticed by Darwin and this is what, in our own work, we have called 'male sex drive,'" says Singh. "Male sex drive allows males to sire more progenies by way of inducing females to lay more eggs, as well as by being able to mate with the next generation females. This is because on the average males have longer fertile life spans.
"Molecular evidence shows that male-biased genes (genes expressed in males) tend to evolve faster than female-biased genes. This can only be explained by the Male Sex Drive Theory," he says.
As for why males are constantly on the prowl for female companionship?
"Males are mating all the time because it's fun," explains Singh.
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