Title: Thermal Stress Disrupts Symbiotic Fluid Dynamics in Bobtail Squid Show Chinese title

Title: 热应力破坏短尾乌贼共生流体动力学

Abstract: The impact of thermal stress on beneficial symbiosis, in the face of rapid climate change, remains poorly understood. We investigate this using the model system, Euprymna scolopes, the Hawaiian Bobtail Squid, and its bioluminescent symbiont, Vibrio fischeri, which enables the squid to camouflage itself through counter-illumination. Successful colonisation of the squid by V. fischeri must occur hours after hatching and is mediated by fluid flow due to respiration within the squid mantle cavity. To study this process, we develop a mathematical model using the Method of Regularised Stokeslets to simulate the flow and resulting bacterial trajectories within the squid. We explore how thermal stress, mediated by physiological changes in respiration, ciliary dynamics, and internal geometry, affects this early colonisation by analysing the time bacteria spend in regions crucial to the establishment of symbiosis in these simulations. A variance-based sensitivity analysis of physiologically relevant parameters on these metrics demonstrates that changes in the breath cycle significantly impact and reduce the time bacteria spend in the critical zone within the squid, hindering colonisation. Show Chinese abstract

Abstract: 热应力对有益共生关系的影响，在快速气候变化面前仍知之甚少。 我们使用模式系统，即夏威夷短尾乌贼Euprymna scolopes及其发光共生菌Vibrio fischeri，来研究这一问题，这种共生关系使乌贼能够通过逆光照明进行伪装。 V. fischeri在乌贼体内的成功定殖必须在孵化后数小时内发生，并由乌贼外套膜腔内的呼吸流体流动介导。 为了研究这一过程，我们开发了一个数学模型，使用正则化斯托克斯源方法模拟乌贼体内的流动及由此产生的细菌轨迹。 我们通过分析细菌在这些模拟中建立共生关系的关键区域所花费的时间，探讨了由呼吸生理变化、纤毛动力学和内部几何结构介导的热应力如何影响这一早期定殖过程。 对生理相关参数的基于方差的敏感性分析表明，呼吸周期的变化显著影响并减少了细菌在乌贼关键区域的停留时间，从而阻碍了定殖。