Path Integration in Fiddler Crabs: Its Interaction with Stabilizing Reflexes and Co-Evolution with Social Behavior

University Of Cincinnati Main Campus, Cincinnati OH

Investigators

Abstract

Most animals, including humans, have the ability to know their current location relative to a starting point through a process called path integration. Essentially, they add up (or integrate) all of the movements they make on their outward journey, store this calculation in memory, and use it to return to their starting point. This project aims to dissect the currently unknown sensory and motor mechanisms of path integration and how this process works in relation to two other behaviors with which it is critically intertwined: 1) reflexes that maintain physical and perceptual stability (e.g., the vestibuloocular reflex), and 2) spatially dependent social behavior. Fiddler crabs are an ideal system for studying the mechanisms underlying path integration, since through path integration they form the strictest spatial relationship with home of any animal. Until recently fiddler crabs were thought only to form a strong attachment to their own burrow, but new evidence shows some species remember the locations of several burrows simultaneously. This disparity in spatial memory corresponds with the two major mating systems in the genus, and recent experiments suggest that species from each system have fundamentally different path integration mechanisms that incorporate eye- and body-stabilizing reflexes differently. Spatial orientation mechanisms appear to have co-evolved with changes in mating systems to produce spatial navigation abilities that uniquely adapt a species for its social and ecological contexts. This research will provide a uniquely integrative understanding of the interdependent evolution of spatial cognition and social behavior. The results from this research will answer fundamental concepts in spatial cognition and spatial orientation that will broadly impact the engineering of task-oriented machines. Results on how spatial navigation has evolved to varying degrees of task-dependent complexity have the potential to be materially applied, particularly for the design of robots whose ability to reflexively compensate for disturbances is fully incorporated into their ability to perform path integration. The project will train graduate students, and undergraduate students from minorities underrepresented in the sciences through the Student Achievement in Research and Scholarship (STARS) and Women in Science and Engineering (WISE) programs.