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Nest-to-surf mortality of loggerhead (Caretta caretta) sea turtle hatchlings on Florida’s east coast in 2016Unknown Date (has links)
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
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Fire ant self-assemblagesMlot, Nathaniel J. 13 January 2014 (has links)
Fire ants link their legs and jaws together to form functional structures called self- assemblages. Examples include floating rafts, towers, bridges, and bivouacs. We investigate these self-assemblages of fire ants. Our studies are motivated in part by the vision of providing guidance for programmable robot swarms. The goal for such systems is to develop a simple programmable element from which complex patterns or behaviors emerge on the collective level. Intelligence is decentralized, as is the case with social insects such as fire ants.
In this combined experimental and theoretical study, we investigate the construction of two fire ant self-assemblages that are critical to the colony’s survival: the raft and the tower. Using time-lapse photography, we record the construction processes of rafts and towers in the laboratory. We identify and characterize individual ant behaviors that we consistently observe during assembly, and incorporate these behaviors into mathematical models of the assembly process. Our models accurately predict both the assemblages’ shapes and growth patterns, thus providing evidence that we have identified and analyzed the key mechanisms for these fire ant self-assemblages.
We also develop novel techniques using scanning electron microscopy and micro-computed tomography scans to visualize and quantify the internal structure and packing properties of live linked fire ants. We compare our findings to packings of dead ants and similarly shaped granular material packings to understand how active arranging affects ant spacing and orientation. We find that ants use their legs to increase neighbor spacing and hence reduce their packing density by one-third compared to packings of dead ants. Also, we find that live ants do not align themselves in parallel with nearest neighbors as much as dead ants passively do.
Our main contribution is the development of parsimonious mathematical models of how the behaviors of individuals result in the collective construction of fire ant assemblages. The models posit only simple observed behaviors based on local information, yet their mathe- matical analysis yields accurate predictions of assemblage shapes and construction rates for a wide range of ant colony sizes.
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Fire ants on sea turtle nesting beaches in South Florida, USA, and ST. Croix, USVIUnknown Date (has links)
The red imported fire ant, Solenopsis invicta, is a South American native
introduced in Alabama in the early 20th century. This predatory species has rapidly
spread throughout the southeastern US and parts of the West Indies, inflicting great
ecological and economic damage. For example, Solenopsis invicta is known to attack the
eggs and hatchlings of ground nesting birds and reptiles. The ants swarm into the nests
attacking hatchlings and diminishing their chance for survival. My thesis research aimed
to survey the distribution of ants on sea turtle nesting beaches in South Florida and St.
Croix, USVI, and to evaluate the possible threat of Solenopsis invicta and other predatory
ants to sea turtle hatchlings. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2013.
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Fire AntsRiha, Joyce Marie 09 May 1996 (has links)
Loss is a fundamental part of the human experience, from the loss of security and innocence that comes with the necessary separation of child from parent to the ultimate loss of life. Along the way, there are the losses of jobs, of incomes, of homes; the losses of friendships, of family members, of lovers; the losses of direction, of control, of hope. As cognitive and caring beings, humans struggle to cope with these losses, to greater and lesser degrees of success. This is the theme at the heart of this thesis. Fire Ants is composed of ten short stories, fictive works, which differ in specific subject matter, yet deal unilaterally with issues of loss. Like the venomous creatures that threaten to eat B. D. Packard alive in the title story, life eats away at a number of characters in the collection who are deficient. The narrators in "Aftermath" and "Hues," for example, suffer psychological -- if not physical -- deaths. But not all of the characters lack coping mechanisms, unhealthy as they may sometimes be. As the stories unfold, some characters begin to gain small degrees of perspective and understanding, to learn that while life is full of loss, it is not always entirely bleak. As demonstrated in "Cross Creek," good exists, though it is not always where one might expect it. And life can be full despite loss, as depicted in "Stitches."
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Nutrient Availability Affects Flowering Rate but has Limited Influence on Morphology of the Hooded Pitcher Plant, Sarracenia minor.Lemmons, Justin M. 01 January 2013 (has links)
Carnivorous plants perform as both producers and consumers. Botanical carnivory has evolved in sunny, moist, nutrient-poor environments, and the primary nutrient supplied by prey is proposed to be nitrogen. There is a trade-off between carnivorous and photosynthetic structures which corresponds to degree of carnivory expression and available nutrients. This study was conducted on the hooded pitcher plant, Sarracenia minor, which is a facultative wetland plant and Florida-threatened species. Sarracenia minor is considered a specialist myrmecophage and ants characterize the majority of attracted and captured prey. Ants not only provide nutritional benefit, but also protection against herbivory. A natural population of S. minor in northeast Florida was selected to test response to prey and fertilizer nitrogen in a press-experimental design. Introduced fire ants (Solenopsis invicta) and ammonium nitrate (NH4NO3) were used as prey and fertilizer nitrogen sources, respectively. Treatments included: 1) ant addition; 2) fertilizer addition; 3) ant addition/fertilizer addition; 4) no ants/no fertilizer; 5) control. Treatments were administered biweekly and morphological characteristics and herbivory were measured monthly from April-November 2012. Results indicated no significant treatment effects on plant performance and morphological characteristics, except for a significantly greater number of flowers displayed by the nutrient-deprived group (p < .005). Herbivory by Exyra semicrocea also showed a marginally significant negative effect on the tallest pitchers per ramet. Since nitrogen is primarily stored by pitchers and allocated to new growth in the following growing season, the predictive power of this study may be limited. However, increased flowering rate in the nutrient-deprived group suggests that plants were induced to flower from nutrient stress. Also, a burn at the beginning of the study likely influenced nutrient availability and plant response to experimental treatments. In conclusion, stress may have occurred from both fire and nutrients, and S. minor showed resistance and poor response to nitrogen addition.
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The distribution of predaceous fire ant species on important sea turtle nesting beaches in St. Croix, U.S. Virgin IslandsUnknown Date (has links)
The tropical fire ant, Solenopsis geminata is a New World species with a wide native
range including South America as well as several Caribbean islands. The red imported
fire ant, Solenopsis invicta is native to parts of South America. Both species are known
for preying on sea turtles’ eggs and hatchlings. The objectives of this thesis research
were to conduct follow-up and baseline ant species distribution surveys on four sea turtle
nesting beaches in St. Croix, U. S. Virgin Islands. Tuna baits were set out at beaches;
specimens were collected, frozen, preserved then identified. Results show that there was
a significant change in the fire ants’ distribution at Sandy Point National Wildlife Refuge
(SPNWR) while none were found at Jack Bay. Fire ants were also present on the other
two baseline surveyed nesting beaches. The displacement of S. geminata by S. invicta
was observed at SPNWR, which also was presumed by previous surveys. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
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