Flatworm Injects Sperm Into its Head if Mate Unavailable
Posted on July 2, 2015
Scientists have discovered that the flatworm species Macrostomum hystrix may inject its sperm directly into its head if it fails to find a mate. The discovery was made by researchers at the Universities of Basel and Bielefeld observing the highly transparent creatures.
A self-fertilization known as selfing is sometimes used by animals that are hermaphrodites when there is no other way to reproduce. The flatworm has an unusual selfing procedure where it injects sperm kept in its tail region into its head using its needle-like male copulatory organ. The sperm then migrate through the flatworm's body towards the eggs. The flatworm's head is located on the left side in the above image and the eggs are located in the #4 and #5 regions.
Dr. Steven Ramm, the lead author of the study, says in a statement, "As far as we know, this is the first described example of hypodermic self-injection of sperm into the head. To us this sounds traumatic, but to these flatworms it may be their best bet if they cannot find a mate but still want to reproduce."
The scientists say the unique injecting sperm into head method is needed because there are no internal connections between the worm's male and female reproductive systems. A research on the self-fertilization method was published here on the Proceedings of the Royal Society B.