Effects of Agricultural Pollutants on Stress Hormones and Viral Infection in Larval Salamanders

Davis, Drew R.; Ferguson, Katie J.; Schwarz, Matthew S.; Kerby, Jacob L.

doi:10.1007/s13157-019-01207-1

Cited by 21 publications

(20 citation statements)

References 72 publications

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“…It also allows for sampling the same individual multiple times and over long periods of time, even of small animals that would otherwise have to be sacrificed (Scott & Ellis, 2007). Many studies have provided evidence that water-borne corticosterone provides physiologically relevant estimates that are biologically meaningful (Baugh et al, 2018;Charbonnier et al, 2018;Davis et al, 2019;Gabor et al, 2013Gabor et al, , 2015Gabor et al, , 2016Gabor et al, , 2018Holmes et al, 2016). Because water-borne hormone sampling is still a new method, additional research is necessary to determine the ideal containment time (1 hr, 2 hr, etc.)…”

Section: Discussionmentioning

confidence: 99%

“…More aggressive and more severe infections of Batrachochytrium dendrobatidis (Bd) were associated with higher water-borne corticosterone levels in the Mallorcan midwife toad (Alytes muletensis) and common midwife toad (A. obstetricians; Gabor et al, 2015). Higher water-borne corticosterone levels were associated with higher ranavirus infection intensity in larval western tiger salamanders (Ambystoma mavortium; Davis, Ferguson, Schwarz, & Kerby, 2019). In common midwife toads, Bd infection and higher corticosterone levels were associated with decreased ability of their righting reflex (Gabor et al, 2015).…”

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confidence: 99%

“…Most research considers water-borne hormone sampling valid for a species if it is correlated with hormone levels in plasma (Gabor et al, 2013;Scott & Ellis, 2007). Positive correlations between waterborne corticosterone and plasma corticosterone levels have been found in four amphibian species including adult Túngara frogs (Physalaemus pustulosus;r = .46;Baugh et al, 2018), larval western tiger salamanders (r 2 = .60; Davis et al, 2019), adult San Marcos salamanders (Eurycea nana; r = .87), and adult common midwife toads (r = .86; Gabor et al, 2013). To demonstrate detection of physiologically relevant changes in corticosterone, studies often attempt to increase corticosterone in some individuals by injecting them with ACTH or by exposing them to physical agitation (Baugh et al, 2018;Gabor, Davis, Kim, Zabierek, & Bendik, 2018;Gabor et al, 2016).…”

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confidence: 99%

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Water‐borne and plasma corticosterone are not correlated in spotted salamanders

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et al. 2019

Ecology and Evolution

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Water‐borne hormone measurement is a noninvasive method suitable for amphibians of all sizes that are otherwise difficult to sample. For this method, containment‐water is assayed for hormones released by the animal. Originally developed in fish, the method has expanded to amphibians, but requires additional species‐specific validations. We wanted to determine physiological relevance of water‐borne corticosterone in spotted salamanders (Ambystoma maculatum) by comparing concentrations to those taken using established corticosterone sampling methods, such as plasma. Using a mixture of field and laboratory studies, we compared water‐borne corticosterone levels to other traditional methods of sampling corticosterone for spotted salamander larvae, metamorphs, and adults. Despite multiple attempts, and detecting differences between age groups, we found no correlations between water‐borne and plasma corticosterone levels in any age group. Water‐borne sampling measures a rate of release; whereas plasma is the concentration circulating in the blood. The unique units of measurement may inherently prevent correlations between the two. These two methods may also require different interpretations of the data and the physiological meaning. We also note caveats with the method, including how to account for differences in body size and life history stages. Collectively, our results illustrate the importance of careful validation of water‐borne hormone levels in each species in order to understand its physiological significance.

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Section: Discussionmentioning

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Water‐borne and plasma corticosterone are not correlated in spotted salamanders

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Woodley

Davis

et al. 2019

Ecology and Evolution

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“…This method relies on extracting steroid hormones passively diffused into water through the gills, urine, skin, and feces (Scott et al, 2008). The relationship between water-borne corticosterone and plasma corticosterone has been validated in adult and larval common midwife toads (Alytes obstetricans; Gabor et al, 2013), captive-reared and field-collected adult San Marcos salamanders (Eurycea nana; Gabor et al, 2013), and larval Western Tiger Salamanders (Ambystoma mavortium; Davis et al, 2019). All studies found a significant positive correlation between blood plasma and waterborne corticosterone values.…”

Section: Validation Of Water-borne Corticosterone Profilingmentioning

confidence: 99%

Non-invasive Methods for Measuring and Monitoring Stress Physiology in Imperiled Amphibians

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Global climate change is negatively impacting global biodiversity and ectothermic vertebrates, with amphibians being the most imperiled vertebrate taxa. Increased mean global atmospheric temperatures, high rates of habitat degradation, and exposure to infectious diseases, such as chytridiomycosis, have contributed to population declines and extinctions of rare and endangered amphibian species. Field-based monitoring of physiological endocrine traits can help determine the sub-lethal effects of environmental stressors and provide early alerts when populations are chronically stressed. Recent advances in amphibian stress endocrinology include the development and use of non-invasive methods to quantify the glucocorticoid, or stress biomarker, corticosterone. Non-invasive methods, such as urinary, skin and buccal swabs, and water-borne hormone monitoring methods (suited for terrestrial and aquatic dwelling species), are available to quantify baseline and short-term physiological stress responses of amphibians under field settings. In this review, we illustrate, by using two case studies of aquatic and terrestrial amphibian species, the applications of non-invasive corticosterone monitoring methods to advance the ecological knowledge and conservation of imperiled amphibian species, discuss the limitations of these methods, and provide future directions for the use of non-invasive hormone monitoring methods. We highlight the use of non-invasive field endocrinology methods to monitor the impacts of environmental stressors on the physiology of amphibians, which can be applied to advance ecological research, conservation, and management of imperiled species.

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“…More aggressive and more severe infections of Batrachochytrium dendrobatidis (Bd) were associated with higher water-borne corticosterone levels in the Mallorcan midwife toad (Alytes muletensis) and common midwife toad (A. obstetricians; . Higher water-borne corticosterone levels were associated with higher ranavirus infection intensity in larval western tiger salamanders (Ambystoma mavortium; Davis et al 2019). In common midwife toads, Bd infection and higher corticosterone levels were associated with decreased ability of their righting reflex .…”

Section: Acknowledgmentsmentioning

confidence: 93%

Population Health of Spotted Salamanders (Ambystoma maculatum) in Created Vernal Pools: an Integrative Approach

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Habitat creation is an important tool for conservation to counteract habitat loss and degradation. Vernal pools are susceptible to destruction due to limited detection, protection, and regulation. These wetlands provide fishless breeding habitat for many amphibian species including spotted salamanders (Ambystoma maculatum) in eastern North America. Determining whether created vernal pool habitat is successful is often determined by demographic data of colonizing populations. I suggest that hormone levels, population genetics, and disease prevalence can improve our understanding of population health in created habitat. The goal of this dissertation was to assess the health of spotted salamander larvae in created vernal pools quantified by corticosterone levels, genetic diversity and structure, and ranavirus prevalence. I also wanted to determine if there were habitat characteristics impacting these parameters to inform future construction techniques and produce habitat conducive to healthy colonizing amphibian populations. I examined whether habitat traits influenced corticosterone levels of salamander larvae in created vernal pools. The strongest model predicting corticosterone levels included larval total length, pool-water temperature, year sampled, and pool diameter. Annual variation in corticosterone levels and habitat characteristics, and positive associations with water temperature and salamander body size highlighted the importance of controlling for external influences. The negative association between pool diameter and corticosterone indicated that larvae in larger pools (up to 12.75-m maximum diameter) were less stressed and potentially healthier. Water-borne hormone sampling is relatively new to amphibians, so I attempted to biologically validate the method for spotted salamanders by comparing water-borne and plasma corticosterone concentrations of the same individuals. There were differences in corticosterone concentrations between larvae, metamorphs, and adults, but there were no correlations between water-borne and plasma concentrations for any of the age groups. The two sampling methods have different units of measurement which might affect the association between the two. I evaluated the genetic structure and genetic diversity of spotted salamander larvae in created vernal pools. I also examined whether local habitat characteristics at the pool level influenced effective number of breeders, relatedness, or genetic diversity. The youngest pools exhibited genetic differentiation, founder's effect, and low effective number of breeders. Effective number of breeders was positively associated with pool age, vegetation cover, pool diameter, and sample size. Pool cover and vegetation cover was also negatively associated with relatedness. Allelic richness and expected heterozygosity did not have strong environmental predictors. I surveyed spotted salamander larvae in created vernal pools for ranavirus prevalence and measured viral load in individual larvae. I tested associations between ranavirus prevalenc...

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Effects of Agricultural Pollutants on Stress Hormones and Viral Infection in Larval Salamanders

Cited by 21 publications

References 72 publications

Water‐borne and plasma corticosterone are not correlated in spotted salamanders

Water‐borne and plasma corticosterone are not correlated in spotted salamanders

Non-invasive Methods for Measuring and Monitoring Stress Physiology in Imperiled Amphibians

Population Health of Spotted Salamanders (Ambystoma maculatum) in Created Vernal Pools: an Integrative Approach

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