Behavior

Two sympatric dolphin species, Stenella frontalis and Tursiops truncatus, resident to Little Bahama Bank, Bahamas were found to mostly forage independent of one another, but occasionally foraged in mixed groups. Analysis of over 20 years of data revealed the degree of overlap to be minimal with spatially distinct regions identified for both species, environmental segregation based on depth, bottom type, temperature, and time of day. Results based on observational data indicated significant differences in group size and selected prey. For S. frontalis, lactating females had the most distinct diet, which differed from that of non-reproductively active (NRA) females. Pregnant females had ambiguous prey use results, but diet differences were revealed through nutritional analysis. Lactating females had a higher intake of all nutrients (% moisture, % lipid, % protein, and calories) than pregnant females but lower than NRA females. Mother and calf pairs selected prey for caloric and moisture values. The influence of calves on foraging groups was reflected through discrete differences in all nutrients. Males and females appeared to select the same major prey, but female prey use was much more diverse.

Wading bird foraging success is influenced by many different factors. From January to March 2008, I conducted a small-scale experiment with three captive Scarlet Ibis (Eudocimus ruber) at the Palm Beach Zoo, in West Palm Beach, Florida. Prey density and the presence of conspecifics were manipulated to test for a response by ibis in terms of prey capture rate. Mixed model analysis, when one prey type was available, showed that capture rate increased significantly with prey density and decreased with the presence of conspecifics. When two prey types were available, prey density and the presence of conspecifics had no effect on the capture rates of either prey type. Selectivity analysis revealed that ibis always selected for crayfish in mixed treatments. I hypothesize that the number of prey types available in a treatment played an important role in determining how fish density and the presence of conspecifics affected ibis foraging success.

Invasive ant species often show unicoloniality, forming networks of connected colonies (i.e. supercolonies), which may extend hundreds or even thousands of kilometers. These "supercolonies" lack intraspecific aggression, thus fighting between colonies is absent. Unicoloniality may be an adaptive mechanism that allows for invasive ant species to reach higher population density and achieve ecological dominance. We used aggression assays to study unicoloniality within and between colonies of the invasive brown rover ant, Brachymyrmex obscurior on the Florida Atlantic University campus in Jupiter, FL. We found that the four B. obscurior colonies could be behaviorally divided into two areas: workers from both colonies in either region never showed intraspecific aggression while workers from colonies in opposing areas always showed intraspecific aggression, often fighting to the death. Thus, B. obscurior appears to show very localized unicoloniality, with neighboring colonies forming small supercolonies.

The pyramid ant, Dorymyrmex bureni, is one of the most common and conspicuous ants of open, sandy habitats in the southeastern US. To examine the architecture of D. bureni nests in different habitats, I made wax casts of the subterranean tunnels and chambers of nests in a disturbed college campus site (n=3) and a relatively undisturbed greenway preserve site (n=5). Nests of pyramid ant, Dorymyrmex bureni, consist of two basic units : horizontal chambers and descending shafts connecting them. Chambers near the surface are tunnel-like with branches arranged in a nexus, while deeper chambers were more compact in outline. Chamber height is more or less constant, but chamber shape becomes more complex and lobed in characteristic ways as chambers enlarge. Nests have a top-heavy distribution of chamber area at all sizes because chambers are larger and closer together in the upper nest regions.

A crucial aspect of captive animal care is enrichment, ranging from simple additions of flora to complicated foraging puzzles. Enrichments are vital in creating an environment for animals that is similar to their wild habitat and eliciting natural behaviors. Enrichment is also used to inhibit unnatural or harmful behaviors, like pacing. Commonly, enrichment techniques are not scientifically tested, and the universality of enrichments is rarely scrutinized. This study explores the universality of a "Snak'n'Trim", a hollow ball 10 inches in diameter with a 1 inch opening for food items to be inserted into the ball. Four bears, (two male, two female) were observed for ten weeks, five in the summer and five in the winter. Daily observations were made during baseline and enrichment trials. Behavior frequency was calculated and results indicate a significant (p<.01) difference between baseline and enrichment trials, providing evidence for the efficacy of the Snak'n'Trim.

One mechanism allowing ant species to successfully invade new areas at a rapid pace is unicoloniality, the formation of large networks connecting colonies over hundreds or even thousands of kilometers. These large networks of colonies, or "supercolonies" lack any form of intraspecific aggression, thus fighting between them is absent. I used aggression assays to study unicoloniality between colonies of the invasive difficult ant, Technomyrmex difficilis on the Florida Atlantic University Wilkes Honors College campus and a household located ~32 km northwest from the college. I found that for all trial combinations, no aggression took place among the ants. From these results, I conclude that T. difficilis does display unicoloniality in South Florida.