Interactive effects of road salt and leaf litter on wood frog sex ratios and sexual size dimorphism

Lambert, Max R.; Stoler, Aaron B.; Smylie, Meredith S.; Relyea, Rick A.; Skelly, David K.

doi:10.1139/cjfas-2016-0324

Cited by 32 publications

(26 citation statements)

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“…Although Kloas et al did not test statistically for sex biases nor for differential responses among males and females (they analyzed males and females separately for chemical effects, but not sex × chemical interactions), it appears that females emerged later than males in the control treatment, and that this pattern may have been reversed in their estradiol treatment across both replicate studies. Other studies have reported a lack of biases in control treatments, but sexually dimorphic impacts of various compounds on size at metamorphosis and time to metamorphosis .…”

Section: Discussionmentioning

confidence: 96%

“…However, whether atrazine‐mediated impacts on size at metamorphosis and time metamorphosis are sexually dimorphic remains largely unexplored. Recently, Lambert et al reported that the type of leaf litter input (oak, maple, or no litter input) and road salt input (salt added or not added) interacted to change the degree of size dimorphism between male and female wood frogs, suggesting that sexually dimorphic impacts of EDCs on metamorphosis can occur. Sexually dimorphic impacts, particularly if prevalent and antagonistic across sexes, could potentially explain why effects on timing of metamorphosis are somewhat inconsistent across studies (; but see Rohr and McCoy ).…”

Section: Introductionmentioning

confidence: 99%

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Atrazine feminizes sex ratio in Blanchard's cricket frogs (Acris blanchardi) at concentrations as low as 0.1 μg/L

Hoskins

Boone

2017

Enviro Toxic and Chemistry

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We exposed Blanchard's cricket frogs (Acris blanchardi) to ecologically relevant concentrations (0, 0.1, 1, and 10 μg/L) of a commercial formulation of atrazine throughout the larval period to determine effects on survival, somatic growth and development (time to metamorphosis and mass at metamorphosis), and gonadal development (sex ratio at metamorphosis and the prevalence of testicular ova in phenotypic males). We tested the following hypotheses: 1) atrazine feminizes the sex ratio, 2) atrazine increases the proportion of phenotypic males with testicular ova, and 3) atrazine differentially affects somatic growth (mass at metamorphosis) and development (time to metamorphosis) for males and females. Although the control sex ratio was male-biased, exposure to 0.1 and 10 μg/L atrazine feminized sex ratios, because these treatments produced 51 and 55% fewer males than the control, respectively. We did not observe testicular ova. Atrazine did not impact survival or metamorphosis, and we did not detect sexually dimorphic impacts on time to metamorphosis or mass at metamorphosis. However, males metamorphosed 2.3 d later than females, regardless of treatment. Sex biases in timing of metamorphosis are underexplored in anurans, but if prevalent, could have important implications for theory surrounding the impact of environmental factors on metamorphosis. Our data suggest that cricket frog sex ratios are sensitive to environmentally relevant concentrations of atrazine and that feminization in the field is likely. Environ Toxicol Chem 2018;37:427-435. © 2017 SETAC.

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Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Atrazine feminizes sex ratio in Blanchard's cricket frogs (Acris blanchardi) at concentrations as low as 0.1 μg/L

Hoskins

Boone

2017

Enviro Toxic and Chemistry

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Section: Amphibiansmentioning

confidence: 99%

“…Recent research shows that sublethal salt concentrations can masculinise wood frog metamorphs (Lambert, Stoler, Smylie, Relyea, & Skelly, 2017). Lambert et al (2017) found that road salt concentration of 867 mg Cl − /L decreased the ratio of females in an experimental population by 10%. More research is needed on the role road salt plays in determining the sex of amphibians-the ongoing decline of amphibian diversity and abundance might potentially be exacerbated by such sublethal effects.…”

Section: Amphibiansmentioning

confidence: 99%

A review of the species, community, and ecosystem impacts of road salt salinisation in fresh waters

2019

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Freshwater ecosystems worldwide are threatened by salinisation caused by human activities. Scientific attention on the ecological impacts of salinisation from road deicing salts is increasing exponentially. Spanning multiple trophic levels and ecosystem types, we review and synthesise the ecological impacts of road salt in freshwater ecosystems to understand species‐, community‐, and ecosystem‐level responses. In our review, we identify knowledge gaps that we hope will motivate future research directions. We found that road salts negatively affect species at all trophic levels, from biofilms to fish. The concentration at which road salt triggered an effect varied considerably. Species‐level impacts were generally sub‐lethal, leading to reductions in growth and reproduction, which can be magnified by natural stressors such as predation. Community‐level impacts including reductions of biodiversity were common, leading to communities of salt‐tolerant species, which may have implications for disease transmission from enhanced recruitment of salt‐tolerant host species such as mosquitoes. At the ecosystem level, road salts alter nutrient and energy flow. Contaminated wetlands could see greater export of greenhouse gases, streams will probably export more nitrogen and carbon, and lakes will encounter altered hydrology and oxygen dynamics, leading to greater phosphorus release from sediments. While it is necessary to keep roads safe for humans, the costs to freshwater ecosystems may be severe if actions are not taken to mitigate road salt salinisation. Cooperation among policy makers, environmental managers, transportation professionals, scientists, and the public will be crucial to prevent a loss of ecosystem services including water clarity, drinkable water, recreation venues, and fisheries.

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“…Despite presumptions of genetic sex determination, it is well known that amphibian sexual development can be mediated by environmental conditions during embryonic or larval development (Hayes, ; King, ; Tamschick et al., ; Witschi, ). While recent work has focused on chemical agents (Hayes et al., ; Hermelink et al, ; Lambert, ; Lambert, Giller, Barber, Fitzgerald, & Skelly, ; Lambert, Stoler, Smylie, Relyea, & Skelly, ; Reeder et al., ; Tamschick et al., ), earlier research illustrated that temperature can influence sexual development and even promote sex reversal (Witschi, , , ). Surprisingly, comparatively little work since then has evaluated the relevance and variation of temperature influence on amphibian sexual differentiation.…”

Section: Introductionmentioning

confidence: 99%

Sexual and somatic development of wood frog tadpoles along a thermal gradient

et al. 2018

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All amphibian species are known to have genetic sex determination. However, a variety of environmental conditions can moderate sexual differentiation, in some cases leading to sex reversal and skewed sex ratios. While there has been a recent focus on chemically-induced sex reversal in amphibians, temperature can also influence sexual differentiation. Building upon a classic 1929 study by Emil Witschi, we assessed temperature-mediated sex reversal. Witschi found that the wood frog sex ratio is 100% male at a high temperature (32°C) compared to a 50:50 sex ratio at 20°C. This pattern is consistent with multiple models of environmentally mediated sexual differentiation in vertebrates. To better understand thermally mediated sex reversal, we raised wood frogs at temperature increments of ∼1°C between 19 and 34°C. Mirroring earlier findings, wood frog metamorph sex ratios are indistinguishable from 50:50 at the lowest temperature and entirely male at the highest temperatures. In between, sex ratios become increasingly male-dominated as temperatures increase, implying a steadily increasing tendency toward female-to-male sex reversal in warmer environments. There was no evidence of a threshold temperature effect on reversal patterns. We also show that, compared to males, females metamorphose larger and later in cooler conditions but earlier and smaller under warmer conditions. While the ecological relevance in this species is unknown, these results conform to the Charnov-Bull model of sex determination (in which female-to-male sex reversal can increase fitness to genetic females at higher temperatures), suggesting the system would reward further study.

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Interactive effects of road salt and leaf litter on wood frog sex ratios and sexual size dimorphism

Cited by 32 publications

References 32 publications

Atrazine feminizes sex ratio in Blanchard's cricket frogs (Acris blanchardi) at concentrations as low as 0.1 μg/L

Atrazine feminizes sex ratio in Blanchard's cricket frogs (Acris blanchardi) at concentrations as low as 0.1 μg/L

A review of the species, community, and ecosystem impacts of road salt salinisation in fresh waters

Sexual and somatic development of wood frog tadpoles along a thermal gradient

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