Natural history and ecological observations of a population of Conhaway crayfishes and their symbiotic branchiobdellidan associates

Abstract

Crayfish throughout the holarctic are found in association with an order of worms known as branchiobdellidans. This relationship has been confirmed as a cleaning symbiosis in several species. The Conhaway crayfish,​ Cambarus appalachiensis, is a species of crayfish endemic to the New River Basin in Virginia and West Virginia. We studied a population of ​ C. appalachiensis​ in Sinking Creek in Newport, VA from March 2017 until February 2018. We collected morphological data and quantified the branchiobdellidan communities on 986 individuals, and kept note of egg brooding and young of year throughout the study period. The life cycle of C. appalachiensis was found to be similar to other large-bodied species of Cambarus crayfish. Molting occurred throughout the year, peaking in the months of April and September. This molting served as a disturbance effect to the symbiotic branchiobdellidan community and reset community assembly. The worm communities on larger, recently molted crayfish more closely resembled the less diverse communities on smaller crayfish. Most worms on recently molted crayfish were ones that we know are early colonizers. This thesis work provides the first life history information on a newly described species of Cambarus crayfish and provides both seasonal data on its branchiobdellidan associates and one of the first empirical examples of host ontogeny acting as a disturbance on a symbiotic community.