|Horse hair worm- kaweahoaks.com|
Horse hair worms (Nematomorpha) are aquatic parasitoids with a complicated life cycle. A parasite generally requires the resources of the host but doesn't routinely reduce its chances or reproducing. A parasitoid on the other hand is like an ungrateful parasite in that it either kills or sterilizes its host.
|Horse hair females are larger-okstate.edu|
The worm lays thousands of tiny eggs which develop into 0.01 inch long larvae. Some of these larvae collect on vegetation that is then exposed when water levels go down. Some species will be eaten by grasshoppers or katydids, developing in their hosts until they are ready to spring forth.
|Grasshopper worm- CSU Extension|
Addendum April 7, 2013. Video taken of a horsehair worm on the Master Naturalist field trip is on line at this link.
For closeup pictures of worms and their claspers, see marietta.edu.