The sexual adventures of flatworms

Aditya Rengaswamy | Weird Science

Thinking about animals and sexuality can bring up quite peculiar facts. Those that study animals realize how bizarre some mating rituals are. Some birds act like home decorators, and use objects of one color to decorate their nests and attract mates.

Some animals dance, some animals sing, and Adelie penguins offer engagement stones for choosing female mates! Just when I thought things couldn’t get any weirder, I learned about flatworms. Flatworms are hermaphrodites, which mean they can act as females or males during reproduction. These animals can reproduce asexually or sexually.

Asexual reproduction is achieved through fragmentation and budding. The worm will just split up into multiple animals, effectively creating a clone of itself.

Their ritual for sexual production can be as simple as just having physical contact for sperm to enter an egg. This is similar to human methods, but some species of flatworm use another, more violent method. Let’s take a moment and explore the most bizarre flatworm adventure into sexuality.

A flatworm is squirming around, looking to produce some children. As it eyes its mate, it gets closer. Within moments, both flatworms have positioned themselves to…you guessed it…fence with male genitals. A fierce fight takes place with slashing and dashing. Finally, one of the male organs is pierced, leaving it unable to produce sperm.

However, since flatworms can be both male and female, the “defeated male” becomes the host of the male sperm, and bears the children. These children will be wrapped in a cocoon within the body, and released into the environment later, where they will hatch.

After reading about this and seeing videos to confirm such behavior, I was in awe. I don’t know, nor will I ever know what bearing a child is like (the whole being a male thing), but if a species is willing to “fight” to be the male – I can’t even imagine.

Parents.com put it well when a survey result stated, “[o]ver and over again, many of our respondents used similar images to describe labor pain: intense menstrual cramps combined with internal twisting.” I have no clue what that feels like – but my respect for women who put up with having children has increased tenfold. Well done ladies, well done.

Join me next time as we continue to explore the weird of our universe. From the vast monuments erected by mankind to the peculiar discovery of scientific phenomena, there is plenty left to discover around us.

Aditya Rengaswamy is a sophomore accounting student at CWRU. He enjoys doing various service projects like Kids Against Hunger, being a part of USG, and hanging out with his brothers in OX.