Clarification of current distribution and ecological factors for successful localization in the two invasive freshwater apple snails, the genus Pomacea

阐明了福寿螺和斑螺在东亚和东南亚的分布现状及限制其分布的生态因素。福寿螺的分布范围从东南亚到日本的温带地区（关东平原），而斑福寿螺的分布范围北方以西表岛为界。结果表明，福寿螺与斑螺可以杂交，并在野外发现了杂交螺。杂交螺的分布范围介于两种螺之间，分布范围以韩国釜山为北方。造成种间和杂种间分布范围不同的最重要因素是对冬季低温的耐受程度不同。

We clarified current distribution of two invasive apple snails, Pomacea canaliculata and P. maculata in East and Southeast Asia, and ecological factors restricting their distribution area. Pomacea canaliculata were distributed widely from Southeast Asia to temperate Japan (Kanto Plain), whereas northern disrbitution limit of P. maculata was Iriomote Island. We demonstrated that P. canaliculata and P.maculata could hybridize and found the hybrid snails in field. The hybrid snails had an intermediated distribution range between the two snails with a northern distribution limit of Pusan, Korea. The most important factor causing the different distribution ranges among the species and hybrids were considered to be the different degrees of tolerance to low temperature during winter.