Microsatellite evidence for multiple paternity in non-native populations of Pomacea canaliculata (Caenogastropoda: Ampullariidae) in China

Reproductive success is critical for the establishment and spread of non-native species. The apple snail, Pomacea canaliculata, is a dioecious and internally fertilizing freshwater gastropod that causes serious economic losses in its non-native ranges annually. Previous studies on P. canaliculata using laboratory-controlled experiments indicated that mating with a second male displaces sperm from the first one, suggesting that multiple paternity occurs in this snail. To investigate the occurrence and frequency of multiple paternity in natural populations, we provide results from two polymorphic microsatellite loci in eight egg clutches collected from four localities in China. By genotyping the hatchlings from each population, we found at least one to three siring fathers per clutch. The paternal contributions of the multiply sired clutches were strongly skewed in P. canaliculata. The total population genetic diversity in the hatchlings exhibited higher observed heterozygosity than that in the adult snails. Increased offspring heterozygosity through multiple paternity is a potential mechanism that may aid P. canaliculata in overcoming genetic bottlenecks, and enhance the ability to adapt to new habitats as an invasive species.