Owners Versus Renters: Comparative Homing Behaviors in Primary and Tertiary Burrowing Crayfish

The ability to navigate successfully to and from sites rich in resources is essential for survival for many organisms. In particular, the ability to repeatedly locate a shelter is critical for avoiding predation. Way finding behaviors are observed across the animal kingdom, with both vertebrates and invertebrates demonstrating highly efficient methods of navigating. The spatial scale of the movement may vary with some animals traveling several hundred kilometers while others may only need to travel a few meters. With a rich behavioral repertoire and relatively simple nervous system crayfish prove to be excellent models for comparative research. Studies have demonstrated their abilities to learn locations in arenas using both place and response cues. However, relatively little is known about crayfish in terms of their abilities to return to shelters from foraging excursions. The work presented here aimed to explore the behavioral mechanisms utilized by crayfish when homing to their burrows. Additionally, this study examined two comparative species of crayfish, both of which utilize burrows, but only one constructs the burrows (primary burrowers). More specifically are there differences in their abilities to navigate to the burrows? The crayfish species were selected based on the varying complexity of the environments within which they reside as well as the amount of energy invested in constructing burrows. The research conducted as part of this dissertation highlighted that i) crayfish do home to artificially constructed burrows within a lab setting ii) there were differences in homing behavior between two species with differing use of burrows (highlighting differences in their behavioral ecology) iii) homing to burrow was not based on a local cue associated directly with the burrow and iv) the mechanism for homing to burrows may be similar in both species. The goal of this dissertation was to examine short range homing behaviors in both a primary and tertiary burrowing species. In addition to determining possible homing mechanisms in crayfish, the questions asked were framed in a broader context, keeping in mind the differences in the behavioral ecology of the two species utilized. While exploratory behavior and spatial learning have been examined in crayfish previously, this work has examined possible behavioral mechanisms of homing behavior in two comparative species of crayfish opening up the possibility of species specific differences based on shelter usage in nature