Department of Life Sciences, Texas A&M University-Corpus Christi, Corpus Christi, Texas, United States of America.
PLoS One. 2011;6(6):e21025. doi: 10.1371/journal.pone.0021025. Epub 2011 Jun 7.
Predators can strongly influence prey populations and the structure and function of ecosystems, but these effects can be modified by environmental stress. For example, fluid velocity and turbulence can alter the impact of predators by limiting their environmental range and altering their foraging ability. We investigated how hydrodynamics affected the foraging behavior of the green crab (Carcinus maenas), which is invading marine habitats throughout the world. High flow velocities are known to reduce green crab predation rates and our study sought to identify the mechanisms by which flow affects green crabs. We performed a series of experiments with green crabs to determine: 1) if their ability to find prey was altered by flow in the field, 2) how flow velocity influenced their foraging efficiency, and 3) how flow velocity affected their handling time of prey. In a field study, we caught significantly fewer crabs in baited traps at sites with fast versus slow flows even though crabs were more abundant in high flow areas. This finding suggests that higher velocity flows impair the ability of green crabs to locate prey. In laboratory flume assays, green crabs foraged less efficiently when flow velocity was increased. Moreover, green crabs required significantly more time to consume prey in high velocity flows. Our data indicate that flow can impose significant chemosensory and physical constraints on green crabs. Hence, hydrodynamics may strongly influence the role that green crabs and other predators play in rocky intertidal communities.
掠食者可以强烈影响猎物种群以及生态系统的结构和功能，但这些影响可以被环境压力所改变。例如，流速和湍流可以通过限制其环境范围和改变其觅食能力来改变掠食者的影响。我们研究了水动力如何影响正在全球范围内入侵海洋栖息地的绿蟹（Carcinus maenas）的觅食行为。已知高流速会降低绿蟹的捕食率，我们的研究旨在确定水流影响绿蟹的机制。我们用绿蟹进行了一系列实验，以确定：1）水流是否会改变它们在野外寻找猎物的能力，2）流速如何影响它们的觅食效率，以及 3）流速如何影响它们处理猎物的时间。在一项野外研究中，尽管高流速区域的螃蟹数量更多，但在流速较快的地点，有诱饵的陷阱中捕获的螃蟹明显较少。这一发现表明，较高的流速会损害绿蟹寻找猎物的能力。在实验室水槽实验中，当流速增加时，绿蟹的觅食效率会降低。此外，绿蟹在高流速下消耗猎物所需的时间明显更长。我们的数据表明，水流可能会对绿蟹施加显著的化学和物理限制。因此，水动力可能会强烈影响绿蟹和其他掠食者在潮间带岩石群落中所扮演的角色。
