The potential ecological impact of the exotic snail Pomacea canaliculata on the Thai native snail Pila scutata

The aims of this study were to compare food consumption, growth rates, time to reach food, and food preferences of the golden apple snail (Pomacea canaliculata) and the Thai native snail (Pila scutata). The eggs of the two species collected from natural habitats were hatched in the laboratory. Snails of one month were raised together and separately to determine growth rates and food consumption. It was found that the growth rate of P. canaliculata was significantly faster than that of P. scutata when both were raised together and when they were raised separately. Both snails grew better when raised separately. P. canaliculata consumed significantly more food than P. scutata. When raised separately, P. canaliculata crawled to food at a significantly faster rate than P. scutata. On average, P. canaliculata and P. scutata took 8.2 +/- 3.2 and 15.1 +/- 3.1 min, respectively, to reach the food offered. To test for food preferences, four local species of aquatic plants, namely Hydrilla verticillata, Nymphaea lotus, Salvinia cucullata, and Alternanthera triandra were provided to both snails. It was discovered that P. canaliculata consumed all the four different food species offered. In contrast, P. scutata tended to feed on S. cucullata rather than the other species. It is concluded that P. canaliculata was superior to P. scutata in terms of growth rates, food consumption, and was also non-selective for food and therefore there is no doubt that in a shared habitat, P. canaliculata will influence P. scutata.