Worms Mating with Different Species Live Shorter than those Mating with Same Species

Most of the time mating of two different species fails in producing an offspring. However, when researchers mated female worms with different species, they found that the female worm lived for less time than the females who mated within the same species.

When the researchers examined the transparent worm under a microscope, they observed that the foreign sperm in the ovaries had broken through the uterus. After that, still they were fertilizing eggs in the ovaries which were unable to develop into offspring. The sperm destroyed the organs and moved further into the female body. It resulted in damage to other organs and ultimately, death.

Though experts already know about these worms, they've evolved to be as different as humans and mice, said study author Asher Cutter, Associate Professor of ecology and evolutionary biology at the University of Toronto. This experiment has shown one big difference in their growth. Every species encounters the same problem, whether group of sperm belongs to one male or several, there is a need to compete with each other to fertilize an egg.

Different strategies have been formed by these species.

"Punishing cross-species mating by sterility or death would be a powerful evolutionary way to maintain a species barrier", senior study author Eric Haag, an evolutionary biologist at the University of Maryland, said in a statement.

The reason behind the aggressiveness of the sperms was the competition with other male worms of the species.