MARTIN III, Arthur/L*; MOORE, Paul/A; Bowling Green State University; Bowling Green State University: The effects of shelter occupation on crayfish agonistic interactions

Dominance provides access to resources such as mates, food, shelter, and other objects promoting survivorship and fitness (Wilson 1975). Shelters serve as a good source of protection from predators and conspecifics. The possession of a shelter by a crayfish increases its probability of winning an agonistic encounter. Therefore, the variability of shelter qualities in an environment should influence an individual�s shelter choice. Little is known about crayfish shelter choice and the variability of quality between various shapes and sizes of shelters. The amount of light or darkness within a shelter may be an indication of shelter choice. This may be related to the number of openings on a shelter that allow light to enter. Thigmotactic stimuli may also influence shelter choice indicating tight fit shelters relative to body size are higher quality shelters. Some work has shown that darker shelters may have more influence on indicating a shelter preference in crayfish than do thigmotactic shelters (Steele et. al. 1997). Our study quantifies crayfish social interactions and shelter choice in the presence of conspecifics. Size matched crayfish bouts were analyzed to quantify social dominance hierarchies. Dominant individuals acquire higher quality resources providing an insight to resource shelter quality. The shelters used in this experiment are half-pipe PVC that consists of a variable number of openings and radii. Dominant individuals acquire higher quality resources than subordinate animals, but little evidence supports crayfish social structures and their influence on resource acquisition. Shelter preference and the social dynamics established when competing for such resources is an important study designed to develop an understanding for these interactions in the field.