方形环棱螺规格对中华绒螯蟹捕食行为的影响

为探讨方形环棱螺(Bellamy aquadrata)规格对中华绒螯蟹(Eriocheir sinensis)捕食行为的影响,通过视频监控系统分析大甲宽(43.0±0.5) mm]、小甲宽(38.0±0.5)mm]规格中华绒螯蟹捕食3种规格方形环棱螺壳宽分别为(5.5±0.5) mm、(7.5±0.5)mm、(9.5±0.5) mm]过程中的选择指数、捕食率、捕食行为的差异。结果表明:螺的规格越大,蟹对其选择系数和捕食率越低(P<0.05);蟹与螺的相遇后捕获概率、捕获后摄食概率与蟹的捕食率的趋势一致,但蟹与螺的相遇概率与蟹的捕食率的趋势相反。螺的规格越小,蟹对螺的捕获后摄食概率越大(P<0.05);螺的规格显著影响大规格蟹的静止时间比、移动时间比和处理时间比(P<0.05),但对其搜寻时间比影响不显著(P>0.05);螺的规格越大其逃逸比例越高(P<0.05);蟹的规格越大,螺的逃逸比例越低(P<0.05);蟹对小规格和中规格螺捕食粉碎处理方式比例显著高于大规格螺(P<0.05)。中华绒螯蟹偏爱捕食小规格的方形环棱螺,捕获后能否摄食是影响中华绒螯蟹捕食的重要环节,中华绒螯蟹对方形环棱螺的处理方式随方形环棱螺的规格发生改变。

Effects of the size of Bellamy aquadrata on the predation behavior of the Chinese mitten crab(Eriocheir sinensis)

In order to investigate the effect of Bellamy aquarata size on the predatory behavior of Eriocheir sinensis. In this study, the differences of size selective, predation rate, predation behavior and shell-breaking techniques of large and small size (shell width: 38 ± 2 mm; 43 ± 2 mm) Eriocheir sinensis preying on three sizes (shell width: 5.5 ± 0.5 mm, 7.5 ± 0.5 mm, 9.5 ± 0.5 mm) were analyzed by video surveillance system. The results were as follows: (1) The larger the size of B. aquarata, the lower the selection index and predation rate of E. sinensis. (P < 0.05). (2) The probability of capture upon encounter and the probability of consumption upon capture of E. sinensis and B. aquarata are consistent with the trend of predation rate, but encounter rate of E. sinensis and B. aquarata is opposite to the trend of predation rate; The smaller the size of B. aquarata, the greater the probability of consumption upon capture of B. aquarata (P < 0.05). (3) B. aquarata size significantly affected the proportion of stationary time, moving time and handling time (P < 0.05), but had no significant effect on the proportion of searching time (P > 0.05). (4) The larger the size of B. aquarata, the higher the proportion of successful avoidance (P < 0.05); the larger the size of E. sinensis, the lower the proportion of successful avoidance of B. aquarata (P < 0.05). (5) The proportion of crushing tactics of E. sinensis small and medium sized B. aquarata was significantly higher than that on large sized B. aquarata (P < 0.05). In conclusion, E. sinensis preferred to prey on small-sized B. aquarata. Whether the crab can consumption after capture is an important link in the predation of E. sinensis. Shell-breaking techniques of the E. sinensis to the square ring Oncomelania changes with the size of the square ring edge snail. The shell-breaking techniques of B. aquarata in E. sinensis changed with the size of B. aquarata.