de Pablo L X, Carleton A, Modarres-Sadeghi Y, Clotfelter E D
Department of Biology, Amherst College, Amherst MA 01002, USA.
Present Affiliation: Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80302, USA.
Integr Org Biol. 2024 Jul 12;6(1):obae027. doi: 10.1093/iob/obae027. eCollection 2024.
The caridoid or "tail flip" escape behavior of decapod crustaceans is a model system in neurobiology, but many aspects of its biomechanics are not well understood. To understand how the freshwater virile crayfish interacts with the substrate during the tail flip, we studied tail-flip hydrodynamics and force generation for free-moving animals standing on substrate, as well as tethered animals held at different distances from the substrate. We found no significant differences in force generation when distance from substrate was varied. Particle image velocimetry revealed that vortex formation was similar at all distances, but there were notable differences in interactions between shed vortices and substrate at different distances. Negative vorticity (clockwise flow of water) was observed in tethered animals interacting with the substrate but was largely absent in free-swimming animals. We found no evidence of ground effects enhancing tail flip performance in either tethered or free-swimming individuals, as peak force generation occurred before vortex shedding. This study contributes to our understanding of the crayfish escape response and highlights the need for more work that incorporates free-swimming animals and complex environments in the study of crustacean biomechanics.
十足目甲壳动物的鲎虫样或“尾部翻转”逃逸行为是神经生物学中的一个模型系统，但其生物力学的许多方面尚未得到很好的理解。为了了解淡水雄螯虾在尾部翻转过程中如何与底物相互作用，我们研究了站在底物上的自由活动动物以及与底物保持不同距离的系留动物的尾部翻转流体动力学和力的产生。我们发现，当与底物的距离变化时，力的产生没有显著差异。粒子图像测速技术显示，在所有距离处涡旋形成都相似，但在不同距离处脱落的涡旋与底物之间的相互作用存在显著差异。在与底物相互作用的系留动物中观察到负涡度（水的顺时针流动），但在自由游动的动物中基本不存在。我们没有发现地面效应在系留或自由游动个体中增强尾部翻转性能的证据，因为峰值力的产生发生在涡旋脱落之前。这项研究有助于我们理解小龙虾的逃逸反应，并强调在甲壳类生物力学研究中需要开展更多纳入自由游动动物和复杂环境的工作。
