In what could offer new insight into how the many species on the earth remain distinct from one another, researchers have found that mating with its different species make some worms sterile and even results in their death.
"The results suggest the interaction between sperm and the female reproductive tract as a novel reason for failed mating in worms," said Eric Haag, associate professor of biology at University of Maryland, US.
When researchers mated caenorhabditis worms of different species, they found that the lifespan of the female worms and their number of progeny were drastically reduced compared with females that mated with the same species.
In addition, females that survived cross-species mating were often sterile, even if they subsequently mated with their own species.
When the researchers observed the sterile and dying female worms under a microscope using a fluorescent stain to visualise sperm in live worms, they discovered that the foreign sperm had broken through the sphincter of the worm's uterus and invaded the ovaries.
There, the sperm prematurely fertilised the eggs, which were then unable to develop into viable offspring.
The sperm eventually destroyed the ovaries, resulting in sterility. It then travelled farther throughout the worm's body, resulting in tissue damage and death.
"The findings may be worth investigating in other species as well, because similar coordination problems may be relevant to infertility in other organisms," Haag added.
The study appeared in the journal PLOS Biology.