No evidence for sexual differences in carapace color in a population of Allegheny crayfish
Sexual dichromatism consists of inter-sexual differences in coloration within a species and is widespread among animal taxa. The presence of sexual dichromatism in crayfish has not been well-studied. However, spot patterns in a population of rusty crayfish (Faxonius [Orconectes] rusticus) have recently been demonstrated to be sexually dichromatic, which suggests sexual dichromatism might exist in other species of the genus Faxonius. Intraspecific carapace color variation varies considerably within some populations of Allegheny crayfish (Faxonius [Orconectes] obscurus) although the contributing factor to this variation has not been demonstrated conclusively. Here, I utilize digital image analysis to quantify carapace coloration of a sample of Allegheny crayfish from eastern
Pennsylvania, USA to determine if carapace color variation in this population can be attributed to sexual dichromatism. No significant difference was found in carapace coloration between sampled male and female Allegheny crayfish, which suggests another factor may be responsible for the carapace color variation observed in this population.