How Do Worms Mate?

Hermaphrodites vs. Parthenogenesis

Ancient Greek mythology has given us story after story that has somehow managed to work its way into our everyday language, or at least our everyday world. The tale of Hermaphroditus is about the son of a god who went swimming in a magical pond. The guard of this body of water fell in love with him, but the love was not reciprocated. In the guard's anger, she cast a curse on Hermaphroditus, which gave him both male and female reproductive organs. This is how the word hermaphrodite has slipped into the English lexicon. A hermaphrodite is a biological organism that has both male and female parts, and they occur fairly often in nature. Worms are a natural hermaphrodite, which leads to the common misunderstanding that they fertilize themselves to reproduce. Some earthworms actually do this, though it is certainly not the norm. The earthworms that can fertilize themselves fall under the category of parthenogenesis. That is the scientific work for the process of self-fertilization, which is a much more uncommon practice in the natural world.

Ready to Mate

Worms are relatively simple creatures, meaning that they don't have a bunch of special parts used in the mating process. While this may be true, they certainly have some unique parts that aren't found on other animals or insects. Located about 1/3 of the way down a worm's body is a soft fleshy ring that is thicker than the rest of the body. This ring is called the clitellum, and it is very important in the mating process of a worm. When a worm is ready to mate, the clitellum changes colors. Normally a fleshy pink color like the rest of the worm, it will turn red-orange in color when the worm is looking to mate. Two worms with this dark colored clitellum will find each other and then begin to go through the lengthy process of reproduction until they are ready to give birth.

Mating Process

When two worms are ready to mate, they will line their bodies up against each other, head to tail. They do this to ready themselves for an exchange of sperm. Worms have a sac called a spermatheca, which they use to hold sperm. Slime begins to coat the clitellum, which then hardens to form a tube. When it hardens, it fills up with an embryonic-type liquid that is called albumin. At this point both of the earthworms begin to wriggle out of the slime tube. As they do this, the tube passes over both sex pores. First, the female sex pore deposits ovum, or eggs, into the slime tube. As the worms continue wriggling out, they deposit sperm from their male sex pores. When free of the slime tube, it closes up and the sperm and eggs mix. This sac is carried by a worm until baby worms have developed, at which point the sac breaks open and they squirm free.

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