ARC-supported researchers from The University of Western Australia have found that some fish species are highly selective when it comes to choosing the father of their offspring. ARC Discovery Early Career Researcher Award (DECRA) recipient, Dr Clelia Gasparini, and Associate Professor Jon Evans, have discovered that female Poecilia reticulata (guppy) fish may mate with several males—like many other species—but they also exercise great control over which males will ultimately be successful in fathering their offspring.

The researchers found that females can affect reproductive outcomes and fertilise their eggs by differentially using sperm from different males—speculating that the females may be controlling the way it is stored in their body after mating, as a way of sorting the ‘best’ from the ‘worst’.

The researchers say that the study provided a clear demonstration that female guppies have subtle but powerful control over what happens at the gamete (reproductive cells) level after mating. This research may have implications for our understanding of reproductive processes and evolutionary mechanisms across a range of animal species, and may have important applications to the fields of assisted reproductive technologies and fertility research.

The study has shown not only that sexual selection can continue after mating, but that the females can control this process.

Image: Aquarium fish guppies, male.