Aggressive Interactions and Resource Competition in Relation to Species Displacement Among Crayfish of the Genus Orconectes

Abstract

Aggressive interactions and competition for shelter were studied in simplified laboratory environments among the crayfish O. virilis, O. propinquus and O. rusticus. O. rusticus was clearly superior to O. virilis with O. propinquus generally intermediate. These results are consistent with ongoing displacements in northern Wisconsin [USA]. In another part of the study involving competition for preferred substrate, little displacement occurred even at high densities; caution is suggested in assessing the importance of aggressive interactions to species displacement.