Differences in osmoregulatory behaviors were studied in two stream-dwelling tree frogs (Pseudacris cadaverina and P. regilla) with different natural histories. This study supports the idea that the natural history of a species has a strong effect on behavior associated with osmoregulation.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 149-168). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 95-104). Also available on the World Wide Web.

Critical life history events such as breeding, migration and hibernation must take place in the correct environmental context to minimize deleterious consequences on survival and reproductive fitness. Neuroendocrine mechanisms synchronizing internal physiological states with extrinsic environmental cues are vital to timing life history events appropriately. Secretion of the pineal hormone melatonin is sensitive to light and temperature cues, which provides a physiological indicator of time of day and time of year for organisms. Melatonin influences seasonal reproduction in a variety of vertebrates, likely by altering the synthesis and/or release of reproductive neuropeptides in the brain. The neuropeptides arginine vasotocin and its mammalian homologue, arginine vasopressin, are well-known modulators of reproductive and sociosexual behavior across vertebrate taxa, and are likely targets of melatonin in the context of seasonal reproduction. There is extensive evidence that vasotocin/vasopressin innervation in the brain is subject to seasonal variation, and that this variation is frequently sexually dimorphic. However, evidence that melatonin directly modulates this important neuropeptide system is lacking. Melatonin receptor 1a (MT1 in mammals) may be responsible for mediating melatonin's influence on brain vasotocin, as it is known to regulate seasonal reproduction in a variety of vertebrates. In the present study, I asked whether melatonin influences brain vasotocin in male green treefrogs (Hyla cinerea), and compared the distribution of melatonin receptor 1a in the brain of green treefrogs between sexes and seasons. Adult male and female green treefrogs were collected from field sites in Louisiana during the summer breeding season. Summer animals were acclimated to lab conditions for 3 weeks, then euthanized and their brains collected. Winter animals were maintained in the lab for four months under incrementally changing photo-, thermo-, and hygroperiod regimes that mimicked the transition to winter in their natural habitat, followed by euthanasia and brain collection. A subset of winter males (Experiment 1) were implanted with melatonin-filled or blank silastic capsules for a period of one month prior to euthanasia and brain collection. Brains of these males were processed for vasotocin immunohistochemistry. I quantified AVT-ir cell number in Experiment 1 males in the nucleus accumbens (NAcc), amygdala and caudal striatum (AMG), preoptic area (POA), suprachaismatic nucleus (SCN), and ventral hypothalamus (VH). Melatonin did not influence brain vasotocin-ir cell number in any brain region. Brains from untreated summer and winter males and females were collected and processed for MT1 immunohistochemistry. MT1-ir cells were quantified in the NAcc, striatum (STR), AMG, POA, SCN, and VH. In all regions quantified, reproductively active males had significantly more MT1-ir cells than nonreproductive males. Within the summer breeding season, males had significantly more MT1-ir cells in the NAcc than did reproductively active females. In all other regions there was no significant difference in MT1-ir cell number between reproductively active males and females. Collectively, these data suggest that melatonin modulates vasotocin via MT1. These findings assist in elucidating the neuroendocrine mechanisms by which vertebrates integrate seasonal cues with physiology to correctly time critical life history events.

Orientador: Reginaldo José Donatelli / Resumo: Ecologia e história natural de Phyllomedusa tetraploidea (Anura: Phyllomedusidae), no interior do Estado de São Paulo, Sudeste do Brasil. Phyllomedusa tetraploidea é uma espécie arborícola típica de mata. Foi estudada durante quatro estações reprodutivas em poça temporária no interior do estado de São Paulo. Dados sobre distribuição horizontal, vertical, substrato, distância do corpo d’agua, morfometria, e desovas foram tomados. O padrão reprodutivo em escala temporal é prolongado estando associado ao aumento de temperatura durante a estação chuvosa. Houve dimorfismo sexual sendo as fêmeas maiores e mais pesadas. No uso do habitat a espécie teve preferência por vegetação arbórea, a uma altura média de 2,26 que variou de 0 a mais de5 metros sendo 45,9% dos registros a 1,1 a 2 metros. Dos indivíduos foram registrados empoleirados 36,6% (n = 95) estavam sobre o interior da poça. Seis tipos de poleiros foram utilizados sendo que 57,2% dos registros feitos em substrato arbóreo. Houve preferencia por cobertura vegetal densa. Oito ninhos foram registrados estando dispostos a uma altura média de 2,6 metros sendo a maioria confeccionado em folhas de árvores. Comportamento territorialista entre machos e eventos de predação de adultos foram observados. / Abstract: Ecology and natural history of Phyllomedusa tetraploidea (Anura: Phyllomedusidae), in the interior of the State of São Paulo, Southeastern Brazil. Phyllomedusa tetraploidea is a typical arboreal species of forest. It was studied during four breeding seasons in a temporary pond in the interior of the state of São Paulo. Data on horizontal distribution, vertical distribution, substrate, water body distance, morphometry, and spawning were taken. The reproductive pattern in time scale is prolonged being associated to the increase of temperature during the rainy season. There was sexual dimorphism with females being larger and heavier. In the habitat use the species had a preference for tree vegetation, at an average height of 2.26 m that ranged from 0 to more than 5 meters, with 45.9% of the logs being 1.1 to 2 meters. Of the individuals were recorded perched 36.6% (n = 95) were on the inside of the pond. Six types of perches were used, being 57.2% of records made on tree substrate. There was a preference for dense plant cover. Eight nests were recorded being arranged at an average height of 2.6 meters and the majority were made from leaves of trees. Territorial behavior among males and events of adult predation were observed. / Mestre

Invasive species are one of the major threats to biodiversity and understanding the effects any one invasive species has on members of its new ecosystem can help land managers decide how to best use their limited resources. This study attempted to show the effect Cuban Treefrogs (Osteopilus Septentrionalis) were having on native Florida hylids. For a year, Cuban Treefrogs were removed from three cypress domes and monitored in three other cypress domes, a change in the native population in the experimental domes was the eventual desired effect. Due to weather issues and low native hylid numbers no effect was shown, however due to environmental constraints an effect could not be ruled out either. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Many organisms with complex life cycles undergo transition periods associated with increased vulnerability to predation. Several evolutionary adaptations have been proposed as antipredator defenses for organisms during risky transition periods. These include: shortening of the transition period, parental care, cryptic coloration, and synchrony of risky transitions with large numbers of conspecifics. The results of my research support the hypothesis that synchrony of metamorphosis and emergence from the water and aggregation during the period of transformation may be antipredator defenses for the western toad (Bufo boreas). For some anuran species, synchronous metamorphosis may function as an antipredator adaptation by swamping predators during the period of transformation. I examined the levels of synchrony of emergence from the water of metamorphosing western toads (Bufo boreas) in the presence and absence of a live snake predator, the common garter snake (Thamnophis sirtalis) in a laboratory experiment. To compare between the treatments, I measured the time to emergence from the water, the number of metamorphs emerging together, and the level of aggregation (before and during emergence) of the toads in each treatment. There was a difference between the treatments when all three factors were considered. I attributed these differences to a behavioral response in which B. boreas emerged sooner in the presence of the predator, regardless of whether individual toads had reached the point at which they were physically better suited to the terrestrial environment than the larval environment. Since the Pacific treefrog (Hyla regilla) is also preyed upon by T. sirtalis during the vulnerable period of metamorphosis, I conducted a laboratory experiment to test the effects of the presence of T. sirtalis on 1) aggregation of larval and metamorphosing H. regilla, 2) time to metamorphosis, 3) synchrony of metamorphosis, 4) time to emergence from the water and 5) synchrony of emergence from the water. The only significant effect observed in this experiment was a difference between aggregation levels of H. regilla throughout the experiment. There was, however, a strong trend in which the variances around the mean times to metamorphosis and emergence of the frogs in the control treatments were larger than those in the predator treatments. This could indicate a trend toward synchrony of metamorphosis and emergence for H. regilla in the presence of snake predators. / Graduation date: 1998

Thesis (M.S.)--California Polytechnic State University, 2010. / Title from PDF title page; viewed on March 18, 2010. Major professor: Royden Nakamura, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Biological Sciences." "February 2010." Includes bibliographical references (p. 78-90).

Thesis (Ph. D.) -- University of Tennessee, Knoxville, 2005. / Title from title page screen (viewed on Sept. 6, 2005). Thesis advisor: Arthur C. Echternacht. Thesis advisior: Christine R. B. Boake. Document formatted into pages (xvi, 151 p. : ill. (some col.)). Vita. Includes bibliographical references.

Wetlands in densely urbanized landscapes display altered physical, chemical, and biological features; however, long term trends in these are poorly known. The purpose of this study was to determine if biological, physical, and chemical changes in isolated cypress domes are related to time since incorporation within an urban landscape. Sixteen cypress domes in Tampa, Florida were placed into four decadal age groups based on construction date of residential homes within 200 m of wetland edge, with multiples in each age group: 1970s, 1980s, 1990s, 2000s, and rural sites as regional controls. Each site was visited monthly from July 2008 until July 2009. Hylid treefrogs were monitored using PVC refugia and mating calls. Non-hylid anuran species were monitored using mating call surveys and pitfall traps. Hydrology, pH, and conductivity were recorded, transects were made once at each site from wetland center to terrestrial edge in all four cardinal directions, and all trees greater than 8cm DBH were identified and measured for basal area. The dominant treefrog captured was the exotic O. septentrionalis, which was significantly more abundant in 1990s urban cypress domes than either rural sites or other urban decadal groups. The number of both the exotic O. septentrionalis and the native H. cinerea were positively correlated to more recent decades of development surrounding wetlands. H. squirella was detected at sites where O. septentrionalis was rare, and H. femoralis was found almost exclusively at rural sites. Hydroperiods of all urban cypress domes were three times longer on average than rural sites, and conductivity was significantly elevated at all urban sites. In cypress domes within the 1970s decade group, the relative abundance of Florida "facultative wet" tree species was greater than "obligate wet" tree species suggesting encroachment of Acer rubrum into cypress domes possibly due to decades of fire exclusion. At these long isolated sites exotic plants such as Sapium sebiferum were most abundant. Results indicate rapid changes in both physico-chemical characteristics and anuran composition, and long term effects of decreased treefrog abundance and altered tree community structure following incorporation within the urban landscape.