Where Physics Meets Behavior in Animal Groups

The study of the physics of behavior asks how physical bodies interact with the physical world and with one another. Yet social interactions do not all carry the same physical weight. They live on a scale of tangibility, from effective couplings that shape collective dynamics to literal forces transmitted through contact networks. In this talk, I will illustrate this scale through two insect swarms studied in my lab, combining theory and experiment. First, I will consider fireflies that synchronize their flashes. Their coordination can be described by a spring-like social coupling between oscillatory phases, and in our work, this picture is grounded mechanistically using measured phase-dependent responses and an integrate-and-fire model. Second, and on the high-tangibility end, honeybees physically link their bodies to assemble large suspended clusters. The collective becomes a “material made of bees” with measurable structure and mechanics. Using x-ray tomography, we resolve internal architecture and nematic-like order that constrain force-balance descriptions of load bearing and shape. Overall, this perspective helps disintangle passive physical processes from active behavioral control, and has the potential to bring a deeper understanding of the physics of animal groups.

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