BMI Special Seminar // Andrew Gordus - Untangling the web of behaviors used in spider orb-weaving

Many innate behaviors are the result of several coordinated sensorimotor programs to produce higher-order behaviors. Knowing the underlying cognitive states that encode how these programs are coordinated is often difficult since we simply can’t ask the animal their objective. However, extended phenotypes such as architecture provide us with a window into the mind because the structure itself is a physical record of behavioral intent. A particularly elegant and easily quantifiable structure is the spider orb-web. We have developed a novel assay enabling high-resolution behavioral quantification of web-building by the hackled orb-weaver Uloborus diversus. With a brain the size of a fly’s, the spider U. diversus offers a tractable organism for the study of complex behaviors. Using machine vision algorithms for limb tracking, and unsupervised behavioral clustering methods, we have developed an atlas of stereotyped movements used in orb-web construction. The rules for how these movements are coordinated change during different phases of web construction, and we find that we can predict web-building stages based on these rules alone. Thus, the physical structures of the web explicitly represent distinct phases of behavior. To uncover how this sophisticated algorithm is encoded in the brain, we have assembled a genome, and developed biological assays to understand which neurons and genes are critical to encoding web-building behavior.