In a study carried out withguppy fish(Poecilia reticulata), Australian scientists have found evidence that lLess attractive males have better sperm quality. The research, published in the journalProceedings of the Royal Society B, shows thatthe most striking and exuberantly colored specimens “invest” biologically in their appearance, sacrificing their fertility.
In thepolyandria-when a female mates with multiple males-, thereproductive successof a male depends so much on his ability toget a sexual partneras of theability of your sperm to competeeffectively to achievefertilization. Scientists from the Center for Evolutionary Biology at the University of Western Australia decided to study how these two characteristics are compensated for in males of the guppy fish, also known as the million fish, from Central America and known for its high rate of promiscuity and reproduction.
To mate, the researchers explain, male guppy fish often perform behaviors ranging from courtship, a kind of “ritual dance,” to non-consensual “stealth” mating. Comparing the genetic variations of the specimens with the behaviors they had, they discovered that the males who preferred to perform furtive mating were less conspicuous and were less ornate than those who performed courtship to mate. However,less attractive specimens had better sperm quality, with their sperm swimming faster.
According to Professor Jonathan Evans, who has led the research,These findings support the “sperm competition theory“, which argues that females mate with several males and it is the quality of the sperm and the speed of their sperm that will determine the father of their young.” The reproductive advantage enjoyed by the most attractive males could potentially be offset by the poor execution of his ejaculation during the competition of the sperm “, explains the researcher.
