I haven’t done a Q&A post here in awhile, so I figured I’d tackle an interesting one that recently hit my inbox. This one comes from Jim:
Hi, I want to take some red worms into my 3rd grade class
and talk about vericulture composting. I picked up a worm and it
secrected a yelllow liquid in my hand from the band near its head.
What can I tell the kids it is?
This liquid is known as coelomic fluid, which comes (not too suprisingly) from the ‘coelom’.
So what exactly is the coelom??
It is a large fluid-filled cavity that extends the entire length of the worm, located between the body wall and the alimentary canal (the digestive system). Worms release coelomic fluid for a number of reasons, one of those being stress. As such, Red Worms will sometimes release this liquid as a defense mechanism when they are feeling threatened.
Not that you likely would have wanted to test this out, but according to Edwards and Bohlen (1996), Eisenia fetida (the Red Worm) gets its name from the fact that its coelomic fluid smells like garlic (‘fetid’ basically means foul smelling).
Another interesting tidbit gleaned from Edwards and Bohlen (1996) – there is apparently a species of earthworm known as the “squirter earthworm” (Didymogaster sylvaticus) that can shoot coelomic fluid as far as 30 cm!!
Needless to say, you probably wouldn’t want to pick that one up!
Anyway, Jim – perhaps this was more of an answer than you bargained for (haha), but hopefully it helped!
Edwards, C.A. and P.J. Bohlen. 1996. The biology and ecology of earthworms (3rd Edition). Chapman & Hall, London, 426pp.