Estimating the Overwintering Mortality of the Apple Snail, Pomacea canaliculata (Lamarck) (Gastropoda: Ampullariidae) in a Paddy Field of Southern Japan Using Temperature Data

Abstract

Overwintering mortality of the apple snail, Pomacea canaliculata was investigated in a paddy field of Southern Japan for seven consecutive years. Field data and laboratory experiments revealed snails larger than 6.0 mm exhibited higher cold tolerance than small snails. Seven-years of field data showed that a linear regression explained a close relationship between the overwintering mortality of snails larger than 6.0 mm and the cumulative low temperature calculated as the subtraction of the hourly temperature from 10°C (CLT). A high correlation was also observed between overwintering mortality of snails and the mean temperature between December and February. Thus, temperature data seems to be practical and effective in estimating mortality of field snails during the winter.