Fluctuating chelae asymmetry and territorial agonistic behavior in female Orconectes virilis

Abstract

Fluctuating asymmetry (FA) refers to small deviations from perfect symmetry in bilateral traits and is believed to be a product of genetic and environmental stresses. Additionally, FA is believed to be negatively correlated to higher fitness. Hence, FA suggests that symmetrical individuals should out compete asymmetrical individuals. However, this concept is highly controversial. We investigated the relationship between multiple variables (chelae and antennaea symmetry, average chelae length and width, and carapace length) and outcomes of agonistic encounters among weight-matched female North American freshwater crayfish ( Orconectesvirilis ). Crayfish were collected from Burt Lake near Pellston, Michigan. Our results indicate asymmetric chelae and antennae traits, as well as chelae length and width and carapace length, are not reliable predictors of winners and losers in agonistic interactions between female O.virilis. This suggests that FA is not negatively correlated to a higher fitness, but rather, another morphological feature, chemical signal, or other factor is influential in fight outcomes.