An Analysis of the Ectosymbiotic Relationship Between Crayfish and the Branchiobdellida (Annelida:Clitella)

Crayfish are freshwater crustaceans commonly found in streams, rivers, ponds, lakes, and even muddy fields and bar ditches. They are important members of an ecosystem in which they serve as both predator and prey, and function as a host species for many different symbiotic relationships involving parasitic and commensal lifestyles. The branchiobdellids, commonly known as the crayfish worms, are a group of annelids that utilize the crayfish in an ectosymbiotic nature to increase their chances of survival and reproduction. Both crayfish and branchiobdellids have a worldwide distribution; however the ectosymbiotic relationship between these two organisms has been understudied, and the exact nature in which the branchiobdellids affect the crayfish is in question. Branchiobdellids utilize the crayfish by laying their eggs on the crayfish exoskeleton and persist on the crayfish to protect the eggs during maturation. In order to survive, the branchiobdellids must feed, and perform this task by consuming plant material and smaller invertebrates attached to the crayfish and from the surrounding environment. Branchiobdellids have also been known to consume the crayfish gill tissue creating potential detrimental effects to their host. Crayfish specimens primarily involving Procambarus clarkii, the red swamp crayfish, were collected from various water systems in Texas and New Mexico. Live specimens were dissected and analyzed for any potential parasites. Branchiobdellids were collected from preserved and live specimens, preserved in 70% ethanol, and microscopically examined for species analysis via indicative morphological structures and gut composition.