Pesticide tolerance induced by a generalized stress response in wood frogs (Rana sylvatica)

Juvenile dispersal is important for the persistence of amphibian populations. Previous studies have observed nonrandom orientation in juvenile amphibians emigrating from breeding ponds; however, the environmental cues associated with these movements are not well understood. We examined the emigration behavior of recently metamorphosed juveniles of three pond-breeding amphibian species from three woodland ponds. We found that juvenile small-mouthed salamanders ( Ambystoma texanum (Matthes, 1855)), American toads ( Bufo americanus Holbrook, 1836), and wood frogs ( Rana sylvatica LeConte, 1825) exhibited nonrandom orientation upon exiting the breeding ponds. Furthermore, we found a positive relationship between captures of juvenile small-mouthed salamanders and wood frogs and width of the surrounding forest habitat, indicating that these species are selecting areas with broader forested habitat upon exiting the breeding ponds. Our results indicate that migrating juvenile amphibians may rely on direct environmental cues because the orientation of small-mouthed salamanders and wood frogs was influenced by width of the surrounding forested habitat. These observations support previous studies suggesting that maintaining forest habitat, along at least a portion of breeding ponds, is important for the persistence of amphibian populations.

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Kin recognition by larval wood frogs (Rana sylvatica): effects of diet and prior exposure to conspecifics

Oecologia ◽

10.1007/bf00317596 ◽

1991 ◽

Vol 86 (3) ◽

pp. 319-324 ◽

Cited By ~ 15

Author(s):

George J. Gamboa ◽

Keith A. Berven ◽

Randy A. Schemidt ◽

Thomas G. Fishwild ◽

Kelli M. Jankens

Keyword(s):

Kin Recognition ◽

Rana Sylvatica ◽

Prior Exposure ◽

Wood Frogs

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Sexual differences in color and color change in wood frogs

Canadian Journal of Zoology ◽

10.1139/z91-271 ◽

1991 ◽

Vol 69 (7) ◽

pp. 1963-1968 ◽

Cited By ~ 11

Author(s):

Richard B. King ◽

Bethia King

Keyword(s):

Color Change ◽

Red Light ◽

Green Light ◽

Rana Sylvatica ◽

Sexual Differences ◽

Wood Frog ◽

Color Classification ◽

Wood Frogs ◽

Evolutionary Response ◽

Males And Females

An observer-free method of color classification was used to determine whether wood frogs, Rana sylvatica, exhibit sexual differences in color and color change. Males and females captured from breeding aggregations differed significantly in color: females reflected a greater amount of long-wavelength (yellow–red) light and less short-wavelength (blue–green) light than males. The color difference was not just a result of differences in the state of physiological color change at the time of capture but persisted for a month after capture. Males and females also differed in their color-change responses to black and white backgrounds: both sexes changed in brightness, but only males changed in the relative amount of light reflected at different wavelengths. Wood frog color may function in predator avoidance through crypsis. There was a good match between frogs and some of the leaves from the leaf litter surrounding the breeding ponds. Hypotheses for the development of sexual differences in wood frog color include sexual differences in availability of pigment and pigment precursors, morphological color change, and evolutionary response to different selection pressures.

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Fitness costs of mating with preferred females in a scramble mating system

Behavioral Ecology ◽

10.1093/beheco/arz001 ◽

2019 ◽

Vol 30 (3) ◽

pp. 658-665 ◽

Cited By ~ 2

Author(s):

Lindsey Swierk ◽

Tracy Langkilde

Keyword(s):

Mate Choice ◽

Mating Systems ◽

Rana Sylvatica ◽

Female Offspring ◽

Operational Sex Ratio ◽

Male Choice ◽

Wood Frogs ◽

Multiple Parameters ◽

Fitness Benefits ◽

Male Mate

Abstract Little is known about the operation of male mate choice in systems with perceived high costs to male choosiness. Scramble mating systems are one type of system in which male choice is often considered too costly to be selected. However, in many scramble mating systems, there are also potentially high rewards of male choosiness, as females vary dramatically in reproductive output and males typically mate once per season and/or per lifetime. Using scramble mating wood frogs (Rana sylvatica), we tested whether males gain fitness benefits by mating with preferred females. We conducted choice trials (1 male presented simultaneously with 2 females) and permitted males to mate with their preferred or nonpreferred female. Offspring of preferred and nonpreferred females were reared in the laboratory and field, and we quantified various fitness-relevant parameters, including survivorship and growth rates. Across multiple parameters measured, matings with preferred females produced fewer and lower-quality offspring than did those with nonpreferred females. Our results are inconsistent with the idea that mate choice confers benefits on the choosing sex. We instead propose that, in scramble systems, males will be more likely to amplex females that are easier to capture, which may correlate with lower quality but increases male likelihood of successfully mating. Such male choice may not favor increased fitness when the operational sex ratio is less biased toward males in scramble mating systems but is, instead, a bet-hedging tactic benefitting males when available females are limited.

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Variation in acid tolerance of Connecticut wood frogs: genetic and maternal effects

Canadian Journal of Zoology ◽

10.1139/z85-244 ◽

1985 ◽

Vol 63 (7) ◽

pp. 1647-1651 ◽

Cited By ~ 26

Author(s):

Benjamin A. Pierce ◽

Nalin Sikand

Keyword(s):

Genetic Variation ◽

Acidic Solution ◽

Acid Tolerance ◽

Rana Sylvatica ◽

Larval Survival ◽

Wood Frog ◽

Maternal Factors ◽

Wood Frogs ◽

Significant Difference ◽

Sib Families

Acid tolerance in wood frog (Rana sylvatica) embryos and larvae was examined in full- and half-sib families. Among the embryos, no significant difference in acid tolerance at pH 3.75 was observed among the progeny of males. At pH 4 only slight differences in embryo acid tolerance existed among the progeny of males mated to the same female. Thus, there is relatively little direct genetic variation in embryo acid tolerance. However, progeny from different females differed significantly in their acid tolerance at both pH 4 and pH 3.75, indicating that maternal factors are important in embryo acid tolerance. Whether these maternal factors are genetic is not known. Among larvae, maternal factors did not appear to influence acid tolerance, but significant genetic variation was present. Larval survival in an acidic solution was not correlated with embryo acid tolerance.

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Factors Affecting Variation in Reproductive Traits within a Population of Wood Frogs (Rana sylvatica)

Copeia ◽

10.2307/1445378 ◽

1988 ◽

Vol 1988 (3) ◽

pp. 605 ◽

Cited By ~ 54

Author(s):

Keith A. Berven

Keyword(s):

Reproductive Traits ◽

Rana Sylvatica ◽

Wood Frogs ◽

Factors Affecting

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The effects of food and density on growth and metamorphosis in larval wood frogs (Rana sylvatica) from central Labrador

Canadian Journal of Zoology ◽

10.1139/z90-182 ◽

1990 ◽

Vol 68 (6) ◽

pp. 1221-1226 ◽

Cited By ~ 15

Author(s):

Dennis L. Murray

Keyword(s):

Growth Rate ◽

Larval Stage ◽

Larval Density ◽

Life History Strategy ◽

Rana Sylvatica ◽

Food Density ◽

Immature Stages ◽

Growth Inhibitors ◽

Wood Frogs ◽

Positive Effects

Two experiments were performed on Rana sylvatica tadpoles from central Labrador to test for effects of food and density on growth and metamorphosis. In an experiment examining for the presence of diffusible growth inhibitors, one group of tadpoles was given water treated by adding a high density of sibling tadpoles, and another group was given filtered lake water. No diffusible growth inhibitors existed in this population, as body weight measured weekly, weight at metamorphosis, and duration of larval stage did not differ between control and treated groups. In a food-density experiment, effects of food and larval density were examined by subjecting tadpoles at four different densities to four food levels, creating a 4 × 4 food–density matrix. Food and density both affected growth rate, weight at metamorphosis, and duration of larval stage. Socially governed negative density-dependent interactions are either nonexistent in northern populations, or were completely masked by slight positive effects of grouping. Results suggest that northern larvae differ in life-history strategy from southern populations, and the possibility of overwintering in immature stages of high-latitude populations is discussed.

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Expression profiles of metamorphosis-related genes during natural transformations in tadpoles of wild Wood Frogs (Lithobates sylvaticus)

Canadian Journal of Zoology ◽

10.1139/z2012-074 ◽

2012 ◽

Vol 90 (9) ◽

pp. 1059-1071 ◽

Cited By ~ 12

Author(s):

Laia Navarro-Martín ◽

Chantal Lanctôt ◽

Christopher Edge ◽

Jeff Houlahan ◽

Vance L. Trudeau

Keyword(s):

Gene Expression ◽

Expression Profiles ◽

Rana Sylvatica ◽

Fold Increase ◽

Gonadal Development ◽

Specific Expression ◽

Wood Frogs ◽

Lithobates Sylvaticus ◽

Expression Levels ◽

Gene Expression Levels

Numerous studies using laboratory-reared tadpoles have shown the importance of thyroid hormones (TH), thyroid receptors (TR), and deiodinase (Dio) enzymes during anuran metamorphosis. Our study focuses on the analysis of thyroid-related genes in tadpoles of wild Wood Frogs ( Lithobates sylvaticus (LeConte, 1825); also known as Rana sylvatica (Cope, 1889)) during metamorphosis. Results showed that, in concordance with laboratory-reared studies, thyroid receptor beta (trb) gene expression profiles presented the most marked changes. At climax and compared with premetamorphic stages, brains, tails, and gonad–mesonephros complex (GMC) tissues increased trb expression levels 5-, 21-, and 41-fold, respectively (p < 0.05). In addition, gene expression levels of brain deiodinase type II and III showed opposite trends, where 3-fold decrease and 10-fold increase were, respectively, found. This finding supports the idea that thyroid hormone, as it has been demonstrated in laboratory-reared tadpoles, is also involved in natural metamorphosis in wild tadpoles. Interestingly, and contrary to our predictions, we observed that whole brain corticotropin-releasing factor (crf) and crf receptor 1 (crfr1) gene expression levels significantly decrease through metamorphosis in wild L. sylvaticus tadpoles. Further analyses are required to determine if a role of TH in the timing of anuran gonadal development exists, as well as the importance of cell-specific and tissue-specific expression of crf and crfr1 to metamorphosis.

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