Collective Ecophysiology and Physics of Social Insects

昆虫是地球上最多样化的物种，有500多万种不同的种类，几乎利用了每一种陆地和许多水生和空中的生态位。例如，群居昆虫，即那些根据劳动分工形成具有专门种姓的合作社会的昆虫，在白蚁丘、蝗虫群、蜂群和蜂箱等情况下提供了集体行为的壮观例子。这些集体结构是功能性的，使有机体即使在宏观环境可变的情况下也能保持相对统一的微环境。了解在各种气候和环境中如何实现这一点不仅是生态学或生理学的问题，也是物理学的问题，因为它们不断地与环境交换信息、能量和物质。这项研究着眼于在封闭的环境中使用风扇驱动的主动通风来保持温度的蜂群的集体动态，以及主动附着的蜂群的结构动态，这些蜂群可以通过改变形状来对振动触觉刺激做出反应。虽然目前对活动物质的研究主要集中在相互作用产生的空间和时间模式上，但新的实验和理论方法将集中在活动系统如何在反馈存在的情况下通过耦合形式、流和力来执行功能。生物体生活在不同的环境中，因此必须能够容忍它们所处的宏观环境的变化。它们通过创造利基来抑制大范围的变化，而不是完全孤立自己。在人类社会之外，没有任何地方比群居昆虫更能看到这一点。目前的研究以生物学家获得的经验信息为基础，对这个问题采取了定量的物理方法。它的目的是部分打破物理和生物之间的人为障碍，即非生物和生物之间的人为障碍，通过展示生物如何塑造自己及其非生命的物理环境来实现功能。通过综合流体力学、统计力学和活性物质系统的决策，这项研究将对一系列生物和工程系统产生影响，在这些系统中，行为和决策与流动和力结合在一起。生物的集体行为创造了环境微生态位，缓冲了它们免受环境波动(如温度、湿度、机械扰动等)的影响，从而耦合了生物生理学、环境物理学和种群生态学。目前的研究建议结合生物学实验、理论、计算和机器人仿生学来了解一群蜜蜂如何整合物理和行为线索，达到非平衡的稳定状态，使它们能够抵抗和应对环境中力量和流动的波动。研究人员将结合使用光学和X射线成像技术，分析蜂群如何通过伸展自己来应对机械扰动，从而改变其形状和连通性，并获得稳定性。同样，研究人员将研究蜂群中的蜜蜂如何通过在入口处部署扇形策略来应对环境热扰动，它们使用这种策略来创建强制通风流，使蜜蜂能够集体保持恒定的蜂箱温度。当与两个系统中的定量分析和计算相结合时，研究人员将整合对环境线索(加速度、温度、流量)的感知，并将它们转换为行为输出，使蜂群实现动态动态平衡，这将使用集体机器人进行测试，这些机器人使用简单的代理可以相互感知它们的环境，并对这两个线索做出反应。

Insects are the most diverse species on our planet, numbering more than five million different types, and have exploited nearly every terrestrial and many aquatic and aerial niches. Social insects, those that form cooperative societies with specialized castes based on division of labor, for example, afford spectacular examples of collective behavior in such instances as termite mounds, locust swarms and bee clusters and hives. These collective architectures are functional and allow the organisms to maintain a relatively uniform micro-environment even with a variable macro-environment. Understanding how this is achieved in a variety of climates and environments is not just a problem in ecology or physiology, but also one in physics, given that they exchange information, energy and matter continually with the environment. The study looks at the collective dynamics of bee colonies that maintain their temperature in a closed environment using active ventilation driven by fanning, and the structural dynamics of actively adherent bee clusters that can respond to vibrotactile stimuli by changing their shape. While current studies in active matter primarily focus on the patterns in space and time that result from interactions, the new experimental and theoretical approaches will focus on how active systems can perform functions by coupling form, flows and forces in the presence of feedback. Organisms live in varying environments and must therefore be able to tolerate variations in the macro-environment they inhabit. They do this by creating niches that damp out the large scale variations without completely isolating themselves. Outside human societies, nowhere is this better seen than in social insects. The current study takes a quantitative physical approach to the problem, building on the empirical information obtained by biologists. It aims to partially break down the artificial barrier between physics and biology, i.e. between non-living and living matter by showing how living matter shapes itself and its physical non-living environment to achieve function. By synthesizing aspects of hydrodynamics, statistical mechanics and decision making for active matter systems, the research will thus have impact on a range of biological and engineered systems where behavior and decision making come together with flows and forces.The collective behavior of the organisms creates environmental micro-niches that buffer them from environmental fluctuations e.g. temperature, humidity, mechanical perturbations etc., thus coupling organismal physiology, environmental physics and population ecology. The current study proposes to use a combination of biological experiments, theory, computation and robotic biomimicry to understand how a collective of bees can integrate physical and behavioral cues to attain a non-equilibrium steady state that allows them to resist and respond to environmental fluctuations of forces and flows. The researchers will analyze how bee clusters change their shape and connectivity and gain stability by spread-eagling themselves in response to mechanical perturbations, using a combination of optical and x-ray imaging techniques. Similarly, the researchers will study how bees in a colony respond to environmental thermal perturbations by deploying a fanning strategy at the entrance that they use to create a forced ventilation stream that allows the bees to collectively maintain a constant hive temperature. When combined with quantitative analysis and computations in both systems, the researchers will integrate the sensing of the environmental cues (acceleration, temperature, flow) and convert them to behavioral outputs that allow the swarms to achieve a dynamic homeostasis, that will be tested using collective robotics using simple agents that can sense each other, their environment and move in response to both cues.