Female guppies are selective about which males succeed in becoming their offspring's father, according to a new study.
Researchers at The University of Western Australia (UWA) have discovered that although female guppies can mate with several males, they are selective over which male eventually fathers their offspring.
The findings of the study was published in the October 3 issue of the journal Proceedings of the Royal Society B.
They arrived at this conclusion after conducting research that focused on the paternity success of pairs of rival males (how many eggs each male fertilised compared to the other) in two different settings. In the first, the female guppies were allowed to mate naturally with two male guppies each, and in the second, she was artificially inseminated with the sperm from the same two males.
The two results were strikingly different. In the first scenario, there was a clear choice towards a preferred male being chosen to be the father of most of the female's offspring. However, when the female was artificially inseminated and could not choose, paternity was shared equally between the two males.
"This demonstrates that females receive cues from males that they use to decide which male will fertilise their eggs," said co-author Associate Professor Jonathan Evans of the Centre for Evolutionary Biology at UWA's School of Biological Sciences.
The researchers did not investigate how the female guppies were able to select the sperm they wanted to utilise, but they suspect that the fish could somehow control how many sperm were retained for fertilisation.