How Orb-Weaver Spiders Use Leg posture to Modulate Vibration Sensing of Prey on Webs

Substrate-borne vibrations are a ubiquitous modality of information that animals employ for sensing and communication. It is more sensitive to physical constraints than other sensory modalities, since vibrations must propagate through an often-heterogeneous physical environment and the animal itself before reaching the sensors. Many animals display active behavior or even interact with their target during sensing using this modality, yet the physical principles governing these processes are not well understood.

In this award the investigators will study a model extended sensory system composed of a spider, a web, and a target (prey, mate, invader, etc.), and address the benefits of active behavior for modulation of vibration sensing. Orb-weaver spiders are one of the largest family of spiders (3000+ species) and use sensors on their legs to sense vibrations from the target propagating through the web and their own legs.

Despite their vast evolutionary diversity, many orb-weaver spider species display common behavioral strategies of modulating web building and adjusting leg posture when a target is present to enhance vibration sensing, suggesting the crucial role of underlying physical principles in shaping the evolution of their behavior.

The investigators will explore in a model organism (Uloborus diversus) how active modulation of leg posture by the spider can affect its vibration sensing of the target on orb webs. The approach to the problem will integrate biological experiments, which will quantitatively characterize leg posture behavior and web vibrations, with robophysical and simulation modeling, which will vary system parameters systematically to discover physical principles.

The research will uncover in a model system how animals can take advantage of the physics of vibrations in both the physical environment (web) and biological media (spider itself) using active behaviors. This research will advance the physics of behavior by discovering the physical principles that govern behavior in naturalistic environments. This research will also expand the field of biological active sensing by adding understanding of how animals actively use behaviors to modulate a built substrate as part of the sensing system.

This project will provide interdisciplinary, integrative training for students across all levels from PhD to high school in engineering and biology labs. The PIs will also convert research results into outreach materials and activities for K-12 education. The PIs will collaborate with a local high school and Baltimore Science Center (which offers free access to all Baltimore Public School students) to help broaden participation in STEM in Baltimore, a city with a primarily under-represented, disadvantaged population.

The fundamental understanding from this work will inform the creation of robots equipped with vibration sensors capable of active vibration sensing for remote monitoring of targets (e.g., damage, foreign objects, debris) in suspended structures (e.g., suspension bridges, powerlines, and in-orbit space tethers on satellites and space stations). These robots could help replace humans from dangerous tasks that are required for maintaining the health of the Nation’s infrastructure.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.