Hybridization and Mitochondrial Gene introgression Between an Invasive and a Native Crayfish Species

Occupying freshwaters on six continents, crayfishes are a diverse group of organisms that include many narrowly endemic species and those that are harmful aquatic invaders. Crayfishes have proven to be harmful invasive species throughout the world because of their strong influence on ecosystems and are a leading cause of displacement of native crayfishes. While invasive crayfish effects on ecosystems are well studied, displacement mechanisms are understudied, and cases of hybridization are infrequent. In this project, we have found that non-native Virile Crayfish (Faxonius virilis) have hybridized with native Spot-Handed Crayfish (F. punctimanus) in the Current River watershed, Missouri, U.S.A., as evidenced by a mismatch in mitochondrial COI, microsatellites, and phenotypic data. This represents only the second non-native crayfish species reported to hybridize with a native crayfish in an invaded ecosystem. The consequences of this finding are not fully understood, but this new potential impact of Virile Crayfish invasions could influence management decisions regarding the species. Additionally, caution should be taken when using mitochondrial COI as a genetic barcode for crayfish detections as hybridization may result in misleading data.