The North American crab spider Misumenoides formosipes is a sit-and-wait predator of insect pollinators. Females are relatively sedentary and adult males must search for females within a heterogeneous habitat. Females are receptive to mating immediately after their adult molt and a first sperm priority pattern places a premium on male ability to locate females quickly. It is unknown what cues males use to navigate during searches for females. We report here on the male-biased operational sex ratio, the distances traveled and the possible cues utilized by moving males. Males in field trials moved towards inflorescences when both visual and chemical cues were available, but were less likely to do so when chemical cues were eliminated. Males in lab trials chose an inflorescence over leaf substrates even in the absence of visual cues. These findings support the hypothesis that these spiders utilize floral chemistry as an environmental cue to optimize mate searches. / Department of Biology

Recent studies show that sea turtles use both magnetic and visual cues to successfully orient. Juvenile green sea turtles from the near shore reefs of Palm Beach County, Florida were brought to the lab to determine whether the sun could serve as a visual orientation cue. When tethered during the day in a large outdoor tank west of the ocean, the turtles oriented east to northeast. To determine whether the sun's position was used to maintain their heading, I altered the turtles' perception of time by entraining them to a light cycle advanced by 7 h relative to the natural cycle. When tested afterward in the same outdoor tank the turtles oriented northwest, the predicted direction after compensating for the sun's movement over 7 h across the sky. Orientation was unchanged when the turtles bore magnets that negated the use of magnetic cues. These results are consistent with the hypothesis that the turtles used the sun for orientation. / by Cody Robert Mott. / Thesis (M.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

Typescript. / Bibliography: leaves 239-263. / Microfiche. / xiii, 263 leaves, bound ill. 29 cm

The mechanisms that rodents employ to navigate through their environment have been greatly studied. Cognitive mapping theory suggests that animals use distal cues in the environment to navigate to a goal location (place navigation). However, others have found that animals navigate in a particular direction to find a goal (directional navigation). The rodent brain contains head direction cells (HD cells) that discharge according to the head direction of the animal. Navigation by heading direction is disrupted by lesions of the anterodorsal thalamic nuclei (ADN), many of which are HD cells. Aim 1 tested whether male C57BL/6J mice exhibit direction or place navigation in the Morris water maze. Aim 2 tested the effects of temporary inactivation of the ADN on directional navigation. Together, these data indicate that C57BL/6J mice also exhibit preference for directional navigation and suggest that the ADN may be crucial for this form of spatial navigation. / by Sidney Beth Williams. / Thesis (M.A.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Little is known about the visual capabilities of marine turtles. The ability to discriminate between colors has not been adequately demonstrated on the basis of behavioral criteria. I used a three-part methodology to determine if color discrimination occurred. FIrst, I exposed naèive, light-adapted hatchlings to either a blue, green or yellow light. I manipulated light intensity to obtain a behavioral phototaxis threshold to each color, which provided a range of intensities we knew turtles could detect. Second, I used food to train older turtles to swim toward one light color, and then to discriminate between the rewarded light and another light color ; lights were presented at intensities equally above the phototaxis threshold. Lastly, I varied light intensity so that brightness could not be used as a discrimination cue. Six turtles completed this task and showed a clear ability to select a rewarded over a non-rewarded color, regardless of stimulus intensity. Turtles most rapidly learned to associate shorter wavelengths (blue) with food. My results clearly show loggerheads have color vision. Further investigation is required to determine how marine turtles exploit this capability. / by Morgan Young. / Thesis (M.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.

Worldwide, sea turtles are especially vulnerable immediately after emerging from nests. Many monitoring programs measure hatchling production from nest inventories. These inventories rarely account for mortality occurring post-emergence, leaving an incomplete estimate of hatchling production. This study addresses the nest-to-surf data gap for Florida’s east coast nesting assemblages of loggerhead sea turtles (Caretta caretta). Five locations were surveyed during the 2016 nesting season by using infrared time-lapse imagery, night vision optics, and track maps. Over all beaches, 7.6% of the observed hatchlings did not survive to reach the water. Mortality sources varied by location. Observed predators included: foxes, bobcats, yellow-crowned night herons, ghost crabs, and gulls. Hatchling disorientation and misorientation occurred more frequently in urban areas than natural areas. Factors including number of hatchlings emerging, nest-to-surf distance, and urbanization may help managers estimate nest-to-surf mortality. This study will improve life history models that serve as foundations of conservation management. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection