Predation Of Procambarus Clarkii On Several Aquatic Animal And Recognition Mechanism Aquatic Animal To Procambarus Clarkii

Procambarus clarkii native to southern United States and northern Mexico, is one of the famous invasive species, which have spread all over the world. Studies in recent decade considered that invasion of P. clarkii had great threat on survival of native species, and significantly decreased the local biodiversity. We investigated distribution of P. clarkii in Guilin area, predation on native aquatic animal, and studied the anti-predation response of native aquatic animal to P. clarkii. This article has revealed the recognition mechanism of native species to alien predator, and furtherly understand the ecological impact of P. clarkii on introducing place. The main results are as follows:1. Distribution of P. clarkii in Guilin areaWe selected survey points in 12 counties and suburbs of Guilin area, determined the distribution of P. clarkii in Guilin through interview and field survey. According to the survey results, most people were still short of sufficient understanding of ecological and environmental consequences, which might caused by P. clarkii. It is high time that we widely publicize related knowledge of alien species, improve public consciousness.2. Predation of P. clarkii on several aquatic animalIn order to study the predatory influence of P. clarkii on native aquatic animal, we carried out predatory experiments indoor. Experiment results show that the number of Acanthorhodeus tonkinensis and Rana limnocharis tadpoles preyed by P. clarkii was positively correlated with P. clarkii' body length, however, the number of Microhyla ornata tadpoles and M. nipponensis preyed by P. clarkii was not significantly correlated with P. clarkii' body length, the difference might cause by food choice of P. clarkii.3. Recognition mechanism of aquatic animal to P. clarkiiIntrodution and spread of alien predator have given great threat on the survival of native species, many native species have been effected seriously by alien species. Whether native species recognize alien predator effectively? It is very important to the survival of native species. In order to study the recognition mechanism of native species to alien predator P. clarkii, we used Carassius auratus, M. ornate tadpoles, M. nipponensis as prey (focus animal), and observed recognition ability of focus animal to P. clarkii' visual cues and chemical cues. Chemical cues we used were divided into two kinds, one was diet cues released from P. clarkii while it preyed on focus animal, another was chemical cues released from P. clarkii itself called P. clarkii cues. Our results indicated that C. auratus significantly decreased activity level; M. nipponensis not only decreased activity level, but also change space use, away from P. clarkii; M. ornate tadpoles were away from P. clarkii, but not change significantly. Therefore, we thought that C. auratus, M. ornate tadpoles, M. nipponensis all adopt different anti-predation response to predator's visual cues.When diet cues exposed, both C. auratus and M. nipponensis significantly increased refuge use and decreased activity level, M. ornate tadpoles increased refuge use, these results show that C. auratus, M. nipponensis and M. ornate tadpoles were able to recognize P. clarkii based on diet cues. After P. clarkii cues exposed, C. auratus decreased activity level, M. ornate tadpoles increased refuge use, responsing to P. clarkii cues. Whereas, M. nipponensis neither decreased activity level nor increase refuge use. These native aquatic animal were able to recognize P. clarkii through different recognition mechanism, and advoided attack effectively and increased their survival through the recognition mechanism.