|MadSci Network: Zoology|
Dear Tessa, Those worms on your crayfish are called branchiobdellidans. They are distant relatives of earthworms and leeches. Branchiobdellidans live almost exclusively on crayfishes. Most of them probably feed on the even smaller organisms that are also present on the crayfishes. They are not likely to cause much harm to Lucy. Would you consider leaving them on her? That way, you will have more things to study! If you have a microscope, you may want to look at some of the bigger worms under the microscope. You should see a mouth at one end of the body and a sucker at the other end. The worms use their suckers to attach themselves to the crayfish. Sometimes more than one species of branchiobdellidans may be found on a single crayfish. You may be able to tell some species apart by the different shapes of their bodies. If you place the crayfish in a shallow container of water that will fit under a dissecting microscope, you may see through the microscope what the branchiobdellidans are eating. But if you really want to get rid of them you may have to pick them off one by one with tweezers. The branchiobdellidans that are more likely to harm a crayfish probably live on its gills and other soft tissues. But a crayfish would give you a pretty hard time if you tried to examine, let alone touch, its soft parts. If you need more detailed information on branchiobdellidans (and crayfishes), try the following book. Thorp, J. H. & A. P. Covich (eds.) Ecology & Classification of North American Freshwater Invertebrates. Academic Press (1991). There is also some information about branchiobdellidans at this Web site: http://www.pac.dfo- mpo.gc.ca/sci/sealane/aquac/pages/branapcy.htm Enjoy your Summer. Aydin Orstan
Try the links in the MadSci Library for more information on Zoology.