Habitat Displacement and the Mechanical and Display Functions of Chelae in Crayfish

Abstract

Abstract Crayfish competitive ability has been largely attributed to chela size. However, the manner in which chela size influences social interactions has gone relatively unstudied. We investigated whether crayfish (Orconectes virilis) with fully functioning chelae displace individuals whose mechanical or display function was impaired, forcing them into a sub-optimal, sedimentary habitat. Shelter, cobble, sand, and sediment habitats were constructed in enclosures and glue was used to impair crayfish chelae, immobilizing either just their dactyls or their entire chelipeds. The locations of crayfish within the enclosures were recorded. Results indicate that impairing the display function of chelae prevents crayfish from successfully competing with conspecifics for shelter, while impairing the mechanical function of crayfish chelae does not diminish their competitive ability.