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.

Introgressive hybridization between two non‐native apple snails in China: widespread hybridization and homogenization in egg morphology

“…We did not detect 'pure' P. maculata with both mitochondrial and nuclear maculata-type markers in the Chinese populations, which were also not found in other Asian countries such as Japan and Korea. 35 However, both the 'pure' P. canaliculata (CC) and the CB hybrids were widely distributed throughout southern China, while the CM hybrids had a very limited distribution range. As found in many aquatic invasive species, hybrids may lead to the reduction or extinction of either or both parents by outcompeting their parental taxa due to such factors as more rapid growth, larger size, and stronger fitness.…”

“…[32][33][34] Moreover, crossbreeding of P. canaliculata and P. maculata in the laboratory produced fertile hybrid progeny, indicating a lack of complete reproductive isolation between the two species. 35 The hybrids of these two species exhibited intermediate desiccation and cold tolerance compared with their pure-line parents. 35,36 A previous study indicated that egg mass characteristics, that is the number of eggs per clutch and the egg/hatchling size, are the most concrete distinguishing characteristics between P. canaliculata and P. maculata.…”

“…35 The hybrids of these two species exhibited intermediate desiccation and cold tolerance compared with their pure-line parents. 35,36 A previous study indicated that egg mass characteristics, that is the number of eggs per clutch and the egg/hatchling size, are the most concrete distinguishing characteristics between P. canaliculata and P. maculata. 37 Nevertheless, the egg mass morphological traits of hybrid apple snails have not been well documented.…”

The ecophysiology of apple snails in rice: implications for crop management and policy

“…10 days shorter at 22°C; Seuffert et al ., ). Compared to P. maculata , P. canaliculata appears to have a greater tolerance to low temperatures (Matsukura et al ., ) that has probably allowed this latter species to invade cooler regions (e.g. Chile, Japan).…”

A temperature-dependent physiologically based model for the invasive apple snail Pomacea canaliculata

“…Among the apple snails, only P. canaliculata has been listed among the 100 world worst invaders by the IUCN (Luque et al 2014) due to its ecological, agricultural and economic impacts (Carlsson et al 2004;Cowie 2002;Horgan et al 2014;Nghiem et al 2013) as well as the risk posed to human health (Lv et al 2011). Recent studies showed that P. canaliculata has a higher resistance to both low and high temperatures than other Pomacea species that have also been introduced around the world but have not spread so widely (Matsukura et al 2015;Mu et al 2015), and hence, this capacity is probably another key factor in determining its invasiveness.…”