巴西龟对福寿螺的直接捕食及间接干扰效应

Predation and indirect interference effects of Trachemys scripta elegans on Pomacea canaliculata

【目的】研究巴西龟Trachemys scripta elegans对福寿螺Pomaceaca canaliculata的直接捕食效应,为福寿螺的资源化利用提供参考,并探究巴西龟的间接干扰对福寿螺的影响.【方法】福寿螺与巴西龟共存养殖,定期调查福寿螺的存活和受损情况,确定巴西龟对不同大小福寿螺的控制效果;同时研究在不会被捕杀的情况下,福寿螺感知到同类在被捕食过程中释放的警戒信号后的摄食、生长、存活等方面的变化.【结果】福寿螺在巴西龟的直接捕食作用下,14d后仅1/3的个体存活,其中,小螺（壳高5？15mm）和中螺（壳高15-25mm）的存活率分别降至0和40%,2/3的大螺（壳高25-35mm）存活,但受损率达到存活个体的45%.而在间接干扰作用下,福寿螺摄食量明显下降,相应的个体生长受到抑制,但存活率不受影响.【结论】巴西龟对福寿螺有良好的捕食效果,且会抑制周边感知到捕食风险的其他福寿螺的摄食和生长,本研究可以为福寿螺入侵地和巴西龟原产地（美国）控制福寿螺提供新的思路,并对福寿螺的入侵机制和种群变化研究有一定的参考价值.

【 Objective】To investigate the predatory effect of red-eared slider turtle,Trachernys scriptaelegans 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. cscripta elegans and P. ccnaliculata 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 groupsnails outside the cage net under indirect interference effect of T. scripta elegans were investigated,whichmeans 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 thepredation of 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） sthe 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 interferenthough this treatment exhibited less impact on its survival.【 Conclusion ] scripta elegans has strong predatory effect on the invasive P. canaliculata, that also depresses the feeding and gconspecific 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.