This image depicts an instance of cross-species breeding gone awry. Fluorescence microscopy reveals sperm, in red, invading a female worm’s body. (Photo credit: Gavin Woodruff)
In Caenorhabditis worms, sperm from a foreign species can attack the organs of a female, rendering her sterile or even killing her according to new research.
Researchers believe the ‘killer sperm’ may be the result of a divergence in the evolution of worm species’ sexual organs. For example, hermaphrodite worms—which produce their own sperm and fertilize their own eggs to reproduce—were especially susceptible to sterility and death when mated with males of other species.
The research team believes that the hermaphrodite uterus may have evolved to tolerate ‘gentler’ sperm, but not the larger, more active sperm of non-hermaphrodite species.
Original research paper published in the PLoS Biology on July 29, 2014.
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