I would like to know about the flatworms please
Absolutely!! Flatworms are so wonderfully weird. For starters, as far as I’m aware, all flatworms have both ovaries and testes, which already makes them very different from animals most folks are familiar with. More specifically, the free-living marine flatworms in genus Pseudobiceros, part of the order Polycladida have a really unique way of reproduction.
A few Pseudobiceros species include Bedford’s flatworm (Pseudobiceros bedfordi), below:
And one of my personal favorites, Hancock’s flatworm (Pseudobiceros hancockanus), below:
So! With flatworms having both ovaries AND testes, the issue becomes how to decide who will inseminate whom, and how. This genus’s answer is…..penis fencing!
Flatworms in genus Pseudobiceros use penis fencing to decide which individual will play which role in reproduction. They spar with their penises until one successfully touches and inseminates the other. Sperm is either absorbed through pores in the skin or wounds, or is deposited directly into the loser’s body.
The winner of the duel is the “father,” fertilizes the loser, and leaves. The loser becomes the “mother,” and carries the fertilized eggs. It’s more advantageous to win these duels because it takes a lot of energy to create, carry, and care for the fertilized eggs.
Definitely one of the stranger ways animals reproduce, but I think it’s really interesting! Thank you for asking!
TL,DR; marine flatworms fence with their worm dicks to determine who tops
