Physiology of the Invasive Apple Snail, Pomacea maculata (Perry, 1810), in Louisian

Apple snails are in the Family Ampullariidae, a family of freshwater gastropods. Some species in the genus Pomacea have gained considerable notoriety as very destructive invasive species. Ampullariids have a gill and breathe water; in some species, the mantle cavity is modified into an air sack that may function as a lung or flotation device. Apple snails definitively identified as Pomacea maculata have successfully invaded numerous localities in Louisiana, and studies of the physiology of these animals may enhance our understanding of the biology of highly invasive species and suggest effective approaches to controlling the invasive populations. This study investigated respiration of P. maculata in water and in air and the ability of the animals to survive long-term emersion in a state of aestivation. The ability of the animals to disperse over dry ground was studied. Finally, the anatomy of the gill and lung were examined. The results of the study indicate that the gill and the lung in P. maculata are vascularized, capable of gas exchange, and fully functional, which permits survival and respiration in water and during long- and short-term exposure to air. Both the capacity to sustain travel over dry land and the ability to survive long term aerial exposure in an aestivated state were demonstrated by P. maculata. The major physiological changes observed during aestivation include a decrease in heart rate, a reduction in VO2, and the use of discontinuous respiration. A review of published literature suggests that extensive physiological variation exists among populations of native and invasive P. maculata. In conclusion, P. maculata in Louisiana is well-adapted to life in both water and air, can move overland, and can survive emersion for over a year. These physiological adaptations suggest that controlling the further spread of P. maculata will be very difficult.