Mating Strategies of Invasive Versus Indigenous Crayfish: Multiple Paternity as a Driver for Invasion Success?

The invasive spiny-cheek crayfish (Faxonius limosus) has been able to colonize many European waterbodies since its first introduction into Europe, threatening the indigenous crayfish fauna. The remarkable reproductive plasticity of this species has been suggested as an important factor contributing to the alarming invasiveness of this species. In this study, we compared the reproductive strategies of an invasive (F. limosus) and a sympatric indigenous crayfish (Pontastacus leptodactylus). We questioned if the reproductive abilities, namely parthenogenesis and multiple paternity, may contribute to an ongoing invasion process in the Lower Danube. Using microsatellites, we genotyped the mothers and their offspring from 11 clutches of F. limosus and 18 clutches of P. leptodactylus. While no parthenogenesis has been found in F. limosus populations, multiple paternity has been detected for the first time in both species, with comparable incidence. The results of the study indicate that multiple paternity does not play a dominant role in the successful colonization of F. limosus in the Danube. However, the presented results have to be regarded as a pilot study, with a limited number of samples and loci investigated. Given the relevance of mating system knowledge for management measures, future studies with larger sample number could provide valuable contributions to ongoing conservation actions.