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Michael E. Fraker - One of the best experts on this subject based on the ideXlab platform.
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Risk Assessment and Anti-Predator Behavior of Wood Frog (Rana sylvatica) Tadpoles: A Comparison with Green Frog (Rana clamitans) Tadpoles
Journal of Herpetology, 2010Co-Authors: Michael E. FrakerAbstract:This study combines three experiments that identify how Wood Frog (Rana sylvatica) tadpoles assess risk from chemical cues produced by larval dragonflies (Anax junius) preying on conspecifics. I also compare the results to previous studies using Green Frog (Rana clamitans) tadpoles. The results suggest that Wood Frog tadpoles largely assess predation risk through Anax chemical cues similarly to Green Frog tadpoles. This is to be expected because the tadpoles are congeneric and both face predation from Anax in the field. However, their behavioral response to a particular level of perceived risk differs. Wood Frog tadpoles reduced their total activity (swimming and feeding) for a shorter time than Green Frog tadpoles. Wood Frog tadpoles also reduced their feeding activity more strongly than their swimming activity during cue exposure. I relate the differences between the behavioral responses of Wood Frog and Green Frog tadpoles to differences in their life-history strategies.
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Predation risk assessment by Green Frog (Rana clamitans) tadpoles through chemical cues produced by multiple prey
Behavioral Ecology and Sociobiology, 2009Co-Authors: Michael E. FrakerAbstract:Many prey assess predation risk through predator chemical cues. Numerous studies have shown that (1) prey sometimes respond to chemical cues produced by heterospecifics and (2) that many species are capable of associative learning. This study extends this research by focusing on predation risk assessment and antipredator behavior in environments containing chemical cues produced by multiple prey species. The results show that Green Frog ( Rana clamitans ) tadpoles (1) assess risk from the chemical cue produced during predation by a heterospecific (gray tree Frog, Hyla versicolor , tadpoles) and (2) can exhibit similarly strong behavioral responses to a mix of conspecific and heterospecific cues compared to conspecific cue alone, depending on their conditioning environment. I then discuss how the prey choice of the predators and the relative abundances of the prey species should influence the informational value of heterospecific cues.
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perceptual limits to predation risk assessment in Green Frog rana clamitans tadpoles
Behaviour, 2009Co-Authors: Michael E. FrakerAbstract:Summary Many prey assess predation risk through information sources that decline in reliability over time (i.e., the information sources indicate a wider range of potential predation risk levels over time until they provide no information about the current predation risk). However, prey may lack the perceptual ability to accurately assess the reliability of ageing information sources. Here, evidence is provided that suggests that Green Frog {Rana clamitans) tadpoles are unable to assess the age of the chemical cue of predatory larval dragonflies (Anax junius) upon exposure to cue up to 48 h old (but can at 72 h). As a result, tadpoles may overestimate the level of risk when they encounter aged Anax chemical cue, resulting in a disproportionately strong behavioural response. In general, the results suggest that the predation risk assessment of prey depends not only on the objective characteristics of the information source, but also on the perceptual limitations of the prey. Prey may lack the context to accurately assess information sources and may consequently misestimate the actual level of predation risk.
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the influence of the circadian rhythm of Green Frog rana clamitans tadpoles on their antipredator behavior and the strength of the nonlethal effects of predators
The American Naturalist, 2008Co-Authors: Michael E. FrakerAbstract:Prey trade off predation risk and foraging gain in their activity level. Their response to this trade-off mediates direct and indirect interactions between predators and the community (i.e., nonlethal effects). A prey's activity level may also vary independently because of circadian rhythms. I tested how the antipredator behavior of Green Frog (Rana clamitans) tadpoles can be influenced by their circadian rhythm (primarily nocturnal feeding) and how the strengths of nonlethal effects vary in turn. Tadpoles exhibited stronger activity reductions when under predation risk during the day (which may result in stronger resource depression). However, when predation risk was high and persistent, tadpoles remained inactive during both day and night. Consequently, the nonlethal effect on tadpoles (growth rate reduction) was more negative at night. Predicting prey behavior and its effects requires identifying how their perceived risk interacts with and is limited by all factors that can influence their response.
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The effect of hunger on the strength and duration of the antipredator behavioral response of Green Frog (Rana clamitans) tadpoles
Behavioral Ecology and Sociobiology, 2008Co-Authors: Michael E. FrakerAbstract:The activity level of prey reflects a trade-off between predation risk and foraging gain. A number of theoretical and empirical studies have shown that a prey's energetic state or the level of its resource should influence this trade-off (i.e., what the optimal activity level at a level of predation risk is). Here, I show that the energetic state of prey may also influence the duration of their antipredator behavioral response. Green Frog tadpoles (Rana clamitans) reduced their activity level for a shorter time during exposure to the chemical cue of predatory larval dragonflies (Anax spp.) as their time since last feeding increased (i.e., as their energetic state decreased). Interestingly, the tadpoles strongly reduced their activity level upon cue exposure in all treatments. Thus, the relative activity level of tadpoles at different energetic states varied over time.
Michelle D. Boone - One of the best experts on this subject based on the ideXlab platform.
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characterization of gene expression endpoints during postembryonic development of the northern Green Frog rana clamitans melanota
Zoological Science, 2013Co-Authors: Austin S Hammond, Michelle D. Boone, Nik Veldhoen, Marek J Kobylarz, Nicholas R Webber, Jameson Jordan, Vicki Rehaume, Caren C HelbingAbstract:Postembryonic development of a larval tadpole into a juvenile Frog involves the coordinated action of thyroid hormone (TH) across a diversity of tissues. Changes in the Frog transcriptome represent a highly sensitive endpoint in the detection of developmental progression, and for the identification of environmental chemical contaminants that possess endocrine disruptive properties. Unfortunately, in contrast with their vital role as sentinels of environmental change, few gene expression tools currently exist for the majority of native North American Frog species. We have isolated seven expressed gene sequences from the Northern Green Frog (Rana clamitans melanota) that encode proteins associated with TH-mediated postembryonic development and global stress response, and established a quantitative real-time polymerase chain reaction (qPCR) assay. We also obtained three additional species-specific gene sequences that functioned in the normalization of the expression data. Alterations in mRNA abundance profiles were identified in up to eight tissues during R. clamitans postembryonic development, and following exogenous administration of TH to premetamorphic tadpoles. Our results characterize tissue distribution and sensitivity to TH of select mRNA of a common North American Frog species and support the potential use of this qPCR assay in identification of the presence of chemical agents in aquatic environments that modulate TH action.
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Juvenile Green Frog (Rana clamitans) predatory ability not affected by exposure to carbaryl at different times during larval development
Environmental toxicology and chemistry, 2011Co-Authors: Melanie J. Davis, Peter Kleinhenz, Michelle D. BooneAbstract:Larval exposure to pesticides can occur at different times during development and can negatively impact amphibian fitness. We examined the effects of larval Green Frog (Rana clamitans) exposure to carbaryl at 2, 4, 8, or 16 weeks of development on juvenile predatory ability. We did not find evidence that predatory ability was affected by exposure to carbaryl, which suggests that carbaryl does not have latent effects on the predatory performance of Green Frogs in subsequent life stages. Environ. Toxicol. Chem. 2011; 30:1618–1620. © 2011 SETAC
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effects of technical grade active ingredient vs commercial formulation of seven pesticides in the presence or absence of uv radiation on survival of Green Frog tadpoles
Archives of Environmental Contamination and Toxicology, 2011Co-Authors: Holly J Puglis, Michelle D. BooneAbstract:Commercial formulations of pesticides contain both active and other ingredients. In some instances, the other ingredients have detrimental effects on nontarget species. Other factors such as UV radiation and predator cues have been shown to modify the toxicity of pesticides. In a laboratory study we compared the effects of technical-grade active ingredients to commercial formulations of seven common pesticides in the presence or absence of UV radiation on the survival of Rana clamitans (Green Frog) tadpoles over 96 h. We found a significant difference in the survival of tadpoles in technical-grade active ingredients versus commercial formulations in all of the pesticides tested. We also found that either the presence or the absence of UV radiation affected the survival of tadpoles in five of the seven pesticides tested. These results suggest that there is a need to test the effects of both active ingredients and commercial formulations of pesticides and, also, to include relevant abiotic factors like UV radiation treatments in the testing of pesticides because they can have a dramatic impact on the toxicity of some chemicals.
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Single and interactive effects of malathion, overwintered Green Frog tadpoles, and cyanobacteria on gray treeFrog tadpoles.
Environmental toxicology and chemistry, 2008Co-Authors: Mark J. Mackey, Michelle D. BooneAbstract:Amphibian population declines around the world are associated with invasive species, pesticides, pathogens, habitat destruction, or a combination of factors. Because contamination is widespread, it represents a relevant environmental stress that can affect the ability of organisms to deal with other factors present in the environment. We examined the effects of the insecticide malathion, larger tadpole competitors (Green Frogs, Rana clamitans), and a toxic cyanobacteria (Anabaena spp.) on tadpoles of Cope's gray treeFrog (Hyla chrysoscelis) reared from hatching through metamorphosis in outdoor mesocosms. The response of mass at metamorphosis and time to metamorphosis was significantly affected by exposure to malathion and presence of overwintered Green Frog tadpoles. Malathion generally led to increased mass at metamorphosis, earlier time to metamorphosis, and increased activity during larval development. These results likely stem from short-term increases in periphyton associated with malathion exposure (although these effects were nonsignificant). Exposure of gray treeFrogs to overwintered Green Frog tadpoles led to an earlier time to metamorphosis without differences in mass at metamorphosis and was associated with increased activity in gray treeFrogs. Survival of gray treeFrogs was significantly affected by an interaction of Green Frog and malathion, indicating nonadditive effects of these treatments. Exposure to cyanobacteria had a significant negative effect on Green Frogs but no effect on treeFrogs. Malathion had the strongest effect on the community, but our results indicated that some factors can interact in ways not predicted by single factors alone.
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multiple sublethal chemicals negatively affect tadpoles of the Green Frog rana clamitans
Environmental Toxicology and Chemistry, 2005Co-Authors: Michelle D. Boone, Christine M Bridges, James F Fairchild, Edward E LittleAbstract:Many habitats may be exposed to multiple chemical contaminants, particularly in agricultural areas where fertilizer and pesticide use are common; however, the singular and interactive effects of contaminants are not well understood. The objective of our study was to examine how realistic, sublethal environmental levels of ammonium nitrate fertilizer (0, 10, 20 mg/L and ammonium chloride control) and the common insecticide carbaryl (0 or 2.5 mg/L) individually and interactively affect the development, size, and survival of Green Frog (Rana clamitans) tadpoles. We reared tadpoles for 95 d in outdoor 1,000-L polyethylene ponds. We found that the combination of carbaryl and nitrate had a negative effect on development and mass of tadpoles compared to the positive effect that either contaminant had alone. Presence of carbaryl was generally associated with short-term increases in algal resources, including ponds exposed to both carbaryl and nitrate. However, with exposure to nitrate and carbaryl, tadpole mass and development were not positively affected as with one chemical stressor alone. The combination of these sublethal contaminants may reduce the ability of amphibians to benefit from food-rich environments or have metabolic costs. Our study demonstrates the importance of considering multiple stressors when evaluating population-level responses.
Stephen J. Hecnar - One of the best experts on this subject based on the ideXlab platform.
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spatial scale and determination of species status of the Green Frog
Conservation Biology, 1997Co-Authors: Stephen J. Hecnar, Robert T McloskeyAbstract:Although the importance of spatial scale in determining species status (abundance and distribution) is widely recognized, most ecological investigations have been conducted at local scales. Our goal was to investigate the importance of spatial scale in assessing the status of the Green Frog ( Rana clamitans melanota) in the center of its range in eastern North America. Using repeated surveys at 160 ponds from 1992 to 1994, we investigated patterns of occupancy, abundance, and turnover at local, sub-regional, regional, and geographic scales to determine the status of the Green Frog in southwestern Ontario, Canada. Patterns of pond occupancy were stable at the geographic scale. Occupancy was stable in two regions and decreased in one. At the sub-regional scale, occupancy was stable in six sub-regions, increased in one, and decreased in two. Patterns of adult abundance were stable at the geographic scale. At the regional scale trends in adult abundance were increasing, decreasing, or stable in each of three regions. At the sub-regional scale abundance was stable in three, increasing in one, decreasing in two, and no trend occurred in three sub-regions. At the local scale abundance was stable at 20% of ponds, increased at 17.8%, decreased at 14.4%, and no trend existed at 47.8%. Colonization and extinction rates ranged from 0 to 0.20 and 0 to 0.35 ponds/pond occupied/year, respectively, and differed among regions. Local extinctions took place at 25% of ponds during the study, but no sub-regional or regional scale extinctions occurred. Small populations (<10 adults/pond) were prone to local extinction. Determination of the status of the Green Frog is scale dependent. Although Green Frog populations are dynamic, it is common and stable at the geographic scale, but its status varies among regions or sub-regions. Although processes that negatively affect a species may operate at the local scale, a large-scale perspective is necessary to determine status. Aunque la importancia de la escala especial para la determinacion del estatus de la especie (abundancia y distribucion) es ampliamente reconocida, la mayoria de las investigaciones, ecologicas se ban conducido en escalas locales. Nuestra meta fue investigar la importancia de la escala especial en la evaluacion del estatus de la rana verde ( Rana clamitans melanota) en el centro de su rango de distribucion en el este de Norte America. Mediante muestreos repetidos en 160 estanques de 1992 a 1994 investigamos los patrones de ocupacion, abundancia y reemplazo en escalas local, sub-regional, regional y geografica pera determinar el estatus de la rana verde en el suroeste de Ontario, Canada. Los patrones de ocupacion de estanques fueron estables en la escala geografica. La ocupacion fue estable en dos regiones y decrecio en una. En la escala sub-regional la ocupacion fue estable en seis sub-regiones, se incremento en una y decrecio en dos. En la escala regional la abundancia de adulto tendio a incrementar, decrecer o estabilizarse en cada uno de las tres regiones. En la escala sub-regional la abundancia fue estable en tres sub-regiones, incremento en una, decrecio en dos y no hubo tendencia en tres. En la escala local, la abundancia fue estable en 20% de los estanques, incremento en 17.8%, decrecio en 14.4% y no hubo tendencia en 47.8%. Las tasas de colonizacion y extincion variaron entre 0 a 0.20 y 0 a 0.35 estanques/estanque ocupado/ano respectivamente, y fueron diferentes entre regiones. Durante el estudio ocurrieron extinciones locales en 25% de los estanques, pero no ocurrieron extinciones en la escala sub-regional o regional. Las poblaciones pequenas (<10 adultos/estanque) fueron vulnerables a la extincion local. La determinacion del estatus de la rana verde depende de la escala considerada. Aunque las poblaciones de rana verde son dinamicas, son comunes y estables en la escala geografica, pera su estatus varia entre regiones o subregiones. No obstante que los procesos que afectan negativamente a una especie pueden operar en la escala local, se requiere de una perspectiva a gran escala para determinar el estatus.
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Spatial Scale and Determination of Species Status of the Green Frog
Conservation Biology, 1997Co-Authors: Stephen J. Hecnar, Robert T. M'closkeyAbstract:Although the importance of spatial scale in determining species status (abundance and distribution) is widely recognized, most ecological investigations have been conducted at local scales. Our goal was to investigate the importance of spatial scale in assessing the status of the Green Frog ( Rana clamitans melanota) in the center of its range in eastern North America. Using repeated surveys at 160 ponds from 1992 to 1994, we investigated patterns of occupancy, abundance, and turnover at local, sub-regional, regional, and geographic scales to determine the status of the Green Frog in southwestern Ontario, Canada. Patterns of pond occupancy were stable at the geographic scale. Occupancy was stable in two regions and decreased in one. At the sub-regional scale, occupancy was stable in six sub-regions, increased in one, and decreased in two. Patterns of adult abundance were stable at the geographic scale. At the regional scale trends in adult abundance were increasing, decreasing, or stable in each of three regions. At the sub-regional scale abundance was stable in three, increasing in one, decreasing in two, and no trend occurred in three sub-regions. At the local scale abundance was stable at 20% of ponds, increased at 17.8%, decreased at 14.4%, and no trend existed at 47.8%. Colonization and extinction rates ranged from 0 to 0.20 and 0 to 0.35 ponds/pond occupied/year, respectively, and differed among regions. Local extinctions took place at 25% of ponds during the study, but no sub-regional or regional scale extinctions occurred. Small populations (
Robert T. M'closkey - One of the best experts on this subject based on the ideXlab platform.
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Spatial Scale and Determination of Species Status of the Green Frog
Conservation Biology, 1997Co-Authors: Stephen J. Hecnar, Robert T. M'closkeyAbstract:Although the importance of spatial scale in determining species status (abundance and distribution) is widely recognized, most ecological investigations have been conducted at local scales. Our goal was to investigate the importance of spatial scale in assessing the status of the Green Frog ( Rana clamitans melanota) in the center of its range in eastern North America. Using repeated surveys at 160 ponds from 1992 to 1994, we investigated patterns of occupancy, abundance, and turnover at local, sub-regional, regional, and geographic scales to determine the status of the Green Frog in southwestern Ontario, Canada. Patterns of pond occupancy were stable at the geographic scale. Occupancy was stable in two regions and decreased in one. At the sub-regional scale, occupancy was stable in six sub-regions, increased in one, and decreased in two. Patterns of adult abundance were stable at the geographic scale. At the regional scale trends in adult abundance were increasing, decreasing, or stable in each of three regions. At the sub-regional scale abundance was stable in three, increasing in one, decreasing in two, and no trend occurred in three sub-regions. At the local scale abundance was stable at 20% of ponds, increased at 17.8%, decreased at 14.4%, and no trend existed at 47.8%. Colonization and extinction rates ranged from 0 to 0.20 and 0 to 0.35 ponds/pond occupied/year, respectively, and differed among regions. Local extinctions took place at 25% of ponds during the study, but no sub-regional or regional scale extinctions occurred. Small populations (
Robert T Mcloskey - One of the best experts on this subject based on the ideXlab platform.
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spatial scale and determination of species status of the Green Frog
Conservation Biology, 1997Co-Authors: Stephen J. Hecnar, Robert T McloskeyAbstract:Although the importance of spatial scale in determining species status (abundance and distribution) is widely recognized, most ecological investigations have been conducted at local scales. Our goal was to investigate the importance of spatial scale in assessing the status of the Green Frog ( Rana clamitans melanota) in the center of its range in eastern North America. Using repeated surveys at 160 ponds from 1992 to 1994, we investigated patterns of occupancy, abundance, and turnover at local, sub-regional, regional, and geographic scales to determine the status of the Green Frog in southwestern Ontario, Canada. Patterns of pond occupancy were stable at the geographic scale. Occupancy was stable in two regions and decreased in one. At the sub-regional scale, occupancy was stable in six sub-regions, increased in one, and decreased in two. Patterns of adult abundance were stable at the geographic scale. At the regional scale trends in adult abundance were increasing, decreasing, or stable in each of three regions. At the sub-regional scale abundance was stable in three, increasing in one, decreasing in two, and no trend occurred in three sub-regions. At the local scale abundance was stable at 20% of ponds, increased at 17.8%, decreased at 14.4%, and no trend existed at 47.8%. Colonization and extinction rates ranged from 0 to 0.20 and 0 to 0.35 ponds/pond occupied/year, respectively, and differed among regions. Local extinctions took place at 25% of ponds during the study, but no sub-regional or regional scale extinctions occurred. Small populations (<10 adults/pond) were prone to local extinction. Determination of the status of the Green Frog is scale dependent. Although Green Frog populations are dynamic, it is common and stable at the geographic scale, but its status varies among regions or sub-regions. Although processes that negatively affect a species may operate at the local scale, a large-scale perspective is necessary to determine status. Aunque la importancia de la escala especial para la determinacion del estatus de la especie (abundancia y distribucion) es ampliamente reconocida, la mayoria de las investigaciones, ecologicas se ban conducido en escalas locales. Nuestra meta fue investigar la importancia de la escala especial en la evaluacion del estatus de la rana verde ( Rana clamitans melanota) en el centro de su rango de distribucion en el este de Norte America. Mediante muestreos repetidos en 160 estanques de 1992 a 1994 investigamos los patrones de ocupacion, abundancia y reemplazo en escalas local, sub-regional, regional y geografica pera determinar el estatus de la rana verde en el suroeste de Ontario, Canada. Los patrones de ocupacion de estanques fueron estables en la escala geografica. La ocupacion fue estable en dos regiones y decrecio en una. En la escala sub-regional la ocupacion fue estable en seis sub-regiones, se incremento en una y decrecio en dos. En la escala regional la abundancia de adulto tendio a incrementar, decrecer o estabilizarse en cada uno de las tres regiones. En la escala sub-regional la abundancia fue estable en tres sub-regiones, incremento en una, decrecio en dos y no hubo tendencia en tres. En la escala local, la abundancia fue estable en 20% de los estanques, incremento en 17.8%, decrecio en 14.4% y no hubo tendencia en 47.8%. Las tasas de colonizacion y extincion variaron entre 0 a 0.20 y 0 a 0.35 estanques/estanque ocupado/ano respectivamente, y fueron diferentes entre regiones. Durante el estudio ocurrieron extinciones locales en 25% de los estanques, pero no ocurrieron extinciones en la escala sub-regional o regional. Las poblaciones pequenas (<10 adultos/estanque) fueron vulnerables a la extincion local. La determinacion del estatus de la rana verde depende de la escala considerada. Aunque las poblaciones de rana verde son dinamicas, son comunes y estables en la escala geografica, pera su estatus varia entre regiones o subregiones. No obstante que los procesos que afectan negativamente a una especie pueden operar en la escala local, se requiere de una perspectiva a gran escala para determinar el estatus.
