Cold tolerance of invasive freshwater snails, Pomacea canaliculata, P. maculata, and their hybrids helps explain their different distributions

Abstract

Summary Pomacea canaliculata and P. maculata are invasive freshwater snails originating from South America. The limits of the distributions of the two snails in East and South‐East Asia differ. This study verified a role of cold tolerance in range expansion of the snails and the significance of hybridisation between the two species by comparing overwintering ability and cold tolerance among P. canaliculata, P. maculata and their hybrids. Field observations, laboratory tests and chemical analyses of glucose and glycerol contents in the snails’ organs demonstrated that P. maculata cannot colonise temperate regions because it lacks adequate cold tolerance. The hybrids between P. maculata and P. canaliculata exhibited intermediate cold tolerance that is reflected in their current intermediate distribution between the two species in the invaded areas. This indicates a risk of further spread of the hybrid snails into the temperate regions of the invaded area.