Abstract:
Objective To investigate the predatory effect of red-eared slider turtle, Trachemys scripta elegans on golden apple snail, Pomacea canaliculata so as to provide an effective way for resource utilization of P. canaliculata, and to explore its indirect interference effect on P. canaliculata.
Method T. scripta elegans and P. canaliculata were put in a set of specially-designed plastic aquarium together, control effects of the turtles on various sizes of snails were determined through regular surveys of the survival and damage of P. canaliculata. Meanwhile, the change of feeding, growth and survival of another group snails outside the cage net under indirect interference effect of T. scripta elegans were investigated, which means that the snails were exposed to the caged predators which had no opportunities to attack them but can respond to alarm signals from conspecific snails predated by turtles.
Result The snails under the predation of T. scripta elegans for 14 days, only one third of individuals were still alive, among which, the survival rate of small snails (5-15 mm shell height) and medium snails (15-25 mm shell height) decreased to 0 and 40 percent respectively. Two thirds of large snails (25-35 mm shell height) survived but the injured individuals accounted for 45 percent of the survival. The food intake of the other snails (medium) significantly decreased and growth was restricted under the indirect interference of the turtles, although this treatment exhibited less impact on its survival.
Conclusion T. scripta elegans has strong predatory effect on the invasive P. canaliculata, that also depresses the feeding and growth of surrounding conspecific snails which can perceive the predation risk. These findings would provide new ideas for control of P. canaliculata in its invaded habitat and origin area of turtle (United States), and provide reference values for invasion mechanism and population dynamics research of P. canaliculata.
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