Abstract
Apple snails, P. canaliculata and P. maculata are the two most successful invaders of many macrophytes especially rice in
many countries of the world particularly Southeast Asia. Many studies have been conducted on ecology and management of
P. canaliculata but little is known about the life cycle of P. maculata especially on rice. Therefore, comparative life cycle
studies of P. maculata and P. canaliculata were conducted on rice. Results suggested that P. canaliculata showed
significantly higher growth than P. maculata and matured during the 27th week of development, whereas the latter matured
during the 32nd week. At maturity, no difference was recorded between two species for shell length and width. However,
individuals of both species started consuming rice during the 4th week of the development. Shell length and width of both
species were highly correlated with each other during the entire growth. Egg diameter was significantly higher in P.
canaliculata than P. maculata, however, no significant difference was observed in the number of eggs, hatching period and
rate for the two species. The results obtained can be utilized for the rearing technique of Pomacea spp. on rice to maintain
cultures of different stages to study their unique features contributing to their successful invasion, and suggest appropriate
management strategies to reduce their damage and spread.
