Behavioral modification in Orconectes virilis.

Abstract

Chela size largely determines competitive dominance in Orconectes species. Crayfish having only one functional chela may be at a competitive disadvantage and thus avoid energetically expensive interactions. This study examined whether unimpaired crayfish displace those having only one functional chela, forcing them into a sub-optimal, sedimentary habitat. I tested O. virilis behavior using enclosures placed in the East Branch of the Maple River, Michigan. Treatments in the replicated experiment (N=4) were 4 unimpaired, 4 impaired, and 2 unimpaired/2 impaired crayfish. Crayfish were impaired by gluing closed one chela. Results from the study indicate that losing functionality of one chela does not prevent crayfish from successfully competing with conspecifics for shelter. Chela size may be a bigger determinant of competitive success in O. virilis.