Plethodon wehrlei

Geographic Range

Wehrle's salamanders, Plethodon wehrlei , are distributed throughout the Nearctic region, mainly indigenous to the Appalachian Mountain Plateau. The northernmost region that these salamanders are found is southwestern New York. Their range continues southward into Pennsylvania, southeastern Ohio, West Virginia, southwestern Virginia, and northwestern North Carolina. An isolated population can be found along the border of southeastern Kentucky and northeastern Tennessee.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Within their range, these salamanders are commonly found on wooded hillsides of mountains with elevations above 183 m. Suitable habitats include, red spruce Picea rubens and yellow birch Betula alleghaniensis forests, mixed deciduous and coniferous forests with an abundance of coverage, such as rocks, logs, and leaves. The salamanders live among mature hardwood forests when inhabiting lower elevations. Compared to other salamander species, Wehrle's salamanders typically occupy drier habitats. Although they tolerate drier habitats better than most Plethodon salamanders, Wehrle’s salamanders are not immune to desiccation. When extremely dry conditions exist, these salamanders can burrow down into the soil, and even squeeze between narrow gaps between rocks. Tolerant of these rocky habitats, they can also inhabit cave entrances where light still penetrates.

• Habitat Regions
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• mountains mountains

• Other Habitat Features
• caves

Physical Description

Wehrle's salamanders are considered to be a large, slender member of the Plethodon genus. They have a dark gray or brown body marked on the sides with an irregular row of white, bluish white, or yellow spots or dashes. These spots may be arranged in two rows that are yellow in color in some populations in Tennessee, Kentucky, and West Virginia. These yellow-spotted Wehrle's salamanders occur in isolated populations, and it's unknown if they are a distinct subspecies. Genetic analyses are in progress.

Salamanders inhabiting cave area may demonstrate variation of coloration and distribution of spots. For example, in Roanoke County, Virginia Wehrle’s salamanders living in the Dixie Caverns and Blankenship Cave typically have a purplish brown dorsum profusely frosted with small white flecks and bronzy molding. The dorsal spots of juveniles are often red and arranged in pairs. Adults usually have brassy dorsal flecks with little white dots. In the southern portions of their range, the middorsal area may lack conspicuous markings or have spots arranged in pairs that are yellow, red, or orange-red in color. With the exception of a white or white-blotched throat with frequent small spots extending to the chest, their venter is uniformly gray. Their forelimbs and hindlimbs are nearly equal in size. The webbing of their hindfeet extends to the tips of their first two toes. Typically, their tails are rounded and can grow up to the equivalence of their body length. The number of costal groves they have ranges from 16-18, but most individuals have 17.

Adult salamanders can range from 100-170 mm from head to tail (HT), or 50-75 mm snout-vent length (SVL). The majority of male salamanders’ sizes ranges from 100-160 mm HT, and 50-65 mm SVL, making them slightly smaller than females. Males also distinguish themselves from females by having cloacal papillae and enlarged mental glands.

• Other Physical Features
• ectothermic ectothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger
• sexes shaped differently

Development

Little information specifically regarding the embryonic development of Wehrle's salamanders has been documented. Members of the Plethodon genus have an embryonic development span of approximately 72 days. Unlike most salamander species, Plethodon embryos lack metamorphic changes to the hyobranchial skeleton, a lateral line system, a fin fold on the tail, punitive Leydig cells on the integument, open gill clefts, and a larval dermal bone. The terrestrial larvae hatch from the egg capsules as miniaturized versions of mature adult salamanders. Plethodon larvae also lack a nasolabial groove, which is a diagnostic trait to the Plethodontidae family. They eventually develop this trait as they develop into adults. Plethodon larval direct development allows them to skip the intervening larval stage, making their cycle of metamorphosis incomplete. Hatchlings of members from the Plethodon genus are born with SVL measurements ranging from 12-20 mm and grow rapidly during their first year of life. Wehrle’s salamanders grow approximately 20 mm during their first year of life. Males increase their SVL length by 9-11 mm per year during their second, third, and fourth years of life. In contrast, females’ growth rate is slower during their second year of life with only a 5-7 mm increase in SVL. However, females grow an average of 9 mm annually until they reach sexual maturity. Wehrle’s salamanders are considered juveniles until their SVL reaches approximately 40 mm. At three years of age male Wehrle's salamanders begin to develop mental glands and cloacal papillae. They do not begin breeding until their fourth year. Female sexual maturity is indicated by enlargement of ovarian follicles. Females begin ovarian cycles at around five years of age. The growth rate for both sexes slows drastically after reaching sexual maturity. However, an increase of SVL length is still observed annually.

• Development - Life Cycle
• metamorphosis metamorphosis
• indeterminate growth indeterminate growth

Reproduction

Wehrle's salamanders mate terrestrially. Monogamous mating occurs from March through October depending on the latitude of geographic range. Salamanders inhabiting northern regions, such as New York and Pennsylvania, typically mate in in late September through early October. Males begin to produce spermatophores in August. Female Wehrle’s salamanders lay their eggs during mid-winter through early spring, and the larvae begin to hatch in March. Mating usually happens during March and April for salamanders in West Virginia and Virginia. Unlike populations in the northern geographic range, males begin to produce spermatophores in October. Females will lay their eggs in May and June. The males breed annually, while females typically breed biennially. Male salamanders use pheromones to attract female salamanders. During courtship, the males’ mental glands secrete pheromones on their chins. The pheromones are used to enhance female responsiveness to the males. To administer the pheromone to the females, males wipe their mental glands across the females’ dorsum while scraping her skin with premaxillary teeth. Females may also receive the pheromones by the males slapping their mental glands directly onto their nares. The female will then pick up the sperm caps from spermatophores deposited on the ground, which fertilizes the eggs once they pass through the cloacal orifice.

• Mating System
• monogamous monogamous

Male Wehrle's salamanders typically reach sexual maturity at three years of age. However, they do not begin breeding until the age of four. During mating season, males will evacuate their testes from their internal body. After mating occurs, the testes are then retracted back into the males’ bodies. Female salamanders reach sexual maturity at the age of five. Breeding occurs once annually for male salamanders and most females breed once every two years. Green and Pauley (1987) suggested that mature female salamanders oviposit in deep underground cavities. Only one nesting record has ever been found above ground, which was a clutch of six eggs in a Virginia cave. The eggs are unpigmented but appear as a creamy white color due to being surrounded by the vitelline membrane and two jelly enveloped. Adjoining eggs may be loosely fused together by tubular extensions of the outer envelope when they are laid in grape-like clusters. The average diameter of the outer capsule is 6 mm with the ova measuring 5 mm in diameter. Females will lay between 7-24 eggs; larger females tend to lay more eggs than smaller females. The number of eggs females will lay may also be inferred by the number of their enlarged ova. The length of incubation period for Wehrle’s salamander eggs is unknown. However, the average time from egg-laying until hatching for Plethodon species lasts 72 days. The female salamanders brood the eggs until they are hatched. Once the hatchlings emerge from the egg capsule, they are independent.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • internal internal
• oviparous oviparous

During embryonic development, female Wehrle's salamanders will brood their egg clusters until the hatchlings emerge from their egg capsules. The male salamanders abort paternal care promptly after fertilization.

• Parental Investment
• female parental care female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

The lifespan of Wehrle's salamanders is unknown. However, their close relatives, northern slimy salamanders, Plethodon glutinosus , are believed to live up to 20.1 years in captivity. Staub (2016) reported that members of the Plethodon genus can live up to 36 years in captivity. Longevity within natural habitats for Plethodon salamanders remains unknown.

Behavior

Wehrle's salamanders are primarily sedentary apart from occasionally moving vertically in the soil when surface conditions become too dry. They remain in the same area for their entire lives. Typically, they are solitary animals and do not interact with other salamanders outside of breeding season. From March through October they are active at night to forage for prey on the damp forest floor. In the summer months they remain underground during the day to avoid desiccation. Salamanders inhabiting higher elevations burrow underground for hibernation in late October. They do not emerge from hibernation until late April. Salamanders living in lower elevations burrow beneath the surface for hibernation in late September and do not emerge until March. When threatened, the salamanders will be immobile, avoiding detection. Dodd and Brodie (1976) revealed that Wehrle’s salamanders have the longest immobility duration within their genus. If these salamanders are detected by predators, they can produce odorous, noxious skin secretions that initiate indigestion in smaller predators, making them undesirable to consume. Another anti-predator defense includes tail-base constrictions, allowing the salamanders to detach their tail from their bodies; tails will regenerate completely over time. The detached tail often distracts predators and gives the salamanders time to escape.

• Key Behaviors
• terricolous
• fossorial fossorial
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• hibernation hibernation
• solitary solitary
• territorial territorial

Home Range

The home range of Wehrle's salamanders is unknown. However, it is assumed that they share a similar range with other large Plethodon species. The home range for eastern red-backed salamanders, Plethodon cinereus , is 13 m^2 for juvenile and males and 24 m^2 for females. Wehrle’s salamanders actively defend their territories from other Plethodon species, especially during mating season. They have been known to bite the tails off of smaller Plethodon species.

Communication and Perception

Male Wehrle’s salamanders use their mental gland to secrete substances onto their chins. The secretions are pheromones that are delivered to the female salamanders during courtship. In most Plethodon species, the females follow the males with her chin on his dorsal tail base during courtship. Once males deposit their spermatophore, they continue to lead the female until her cloacal orifice comes into contact with it. Other than to serve as a sexual attractant, the purpose of the pheromone is to increase mating success and female receptivity. These salamanders also rely on their visual senses to analyze their surrounding environments and to communicate with other salamanders.

• Communication Channels
• visual visual
• tactile tactile
• chemical chemical

• Other Communication Modes
• pheromones pheromones

• Perception Channels
• visual visual
• tactile tactile

Food Habits

Wehrle's salamanders nocturnally forage for their prey in low vegetation on the forest floors. However, they have been spotted exposed on the ground surface during the day during wet, foggy, and dark conditions. Occasionally, individuals have been found foraging on tree trunks, specifically in West Virginia. Optimal foraging typically occurs in warm, wet conditions. Their prey varies seasonally and ontogenetically. Generally smaller prey items including ants, springtails, mites, beetles, and spiders are the dietary mainstay of juvenile salamanders. Adult salamanders in Pennsylvania primarily consume European strawberry weevils, Otiorhynchus ovatus . Other adult salamanders mostly consume arthropods, such as beetles, springtails, millipedes, centipedes, orthopterans, crane flies, ants, homopterans, hemipterans, lepidopteran larvae, aphids, fresh water isopods, and weevils. Arachnid prey consists of mites, spiders, and phalangids. Their diets also include gastropods and annelids. During the summer months the majority of prey consumed by both juvenile and adult salamanders includes insect larvae, ants, crickets, spiders, weevils, and orthopterans.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods
  • molluscivore molluscivore
  • vermivore
  • eats other marine invertebrates

• Animal Foods
• insects
• terrestrial non-insect arthropods
• mollusks
• terrestrial worms
• other marine invertebrates

Predation

The only documented predator of Wehrle’s salamanders are northern ring-necked snakes ( Diadophis punctatus edwardsii ). However, other snakes, such as eastern garter snakes ( Thamnophis sirtalis ), ground-foraging birds, and shrews are also believed to prey on these salamanders. When threatened, the salamanders will be immobile, avoiding detection. Dodd and Brodie (1976) revealed that Wehrle’s salamanders have the longest immobility duration within their genus. If these salamanders are detected by predators, they can produce odorous, noxious skin secretions that initiate indigestion in smaller predators, making them undesirable to consume. Another anti-predator defense includes tail-base constrictions, allowing the salamanders to detach their tail from their bodies; tails will regenerate completely over time. The detached tail often distracts predators and gives the salamanders time to escape.

Ecosystem Roles

Wehrele's salamanders are known to host the protozoan Batracholandros magnavulvaris . It is uncommon for these salamanders to be affected by this protozoan. Therefore, they do not have a large impact on their food web. Other members of the genus Plethodon have been known to harbor a protozoan ciliate, Cepedietta michiganesis .

Economic Importance for Humans: Positive

Adult salamanders in Pennsylvania primarily consume European strawberry weevils, Otiorhynchus ovatus . These weevils are a nuisance species due to their detrimental effects of plants, specifically strawberry plants. By Wehrle's salamanders consuming them, humans are able to save money on pest management.

• Positive Impacts
• controls pest population

Economic Importance for Humans: Negative

There are no negative impacts of Wehrle's salamanders on humans.

Conservation Status

Wehrle's salamanders are a species of "Least Concern" on the IUCN Red List. On the US Federal List, CITES, and the State of Michigan List, these salamanders hold no special conservation status. In many areas, they are considered to be the most abundant species within their habitat. However, in North Carolina they are listed as a state-threatened species because their range is restricted to just two northern counties in the state. The conservation status of isolated populations of the yellow-spotted morph Wehrle's salamanders in Kentucky, Tennessee, and West Virginia has yet to be assessed. It's unknown if they are a distinct subspecies. Genetic analyses are in progress, thus making it more critical to preserve the remaining population. Habitat loss due to timber harvesting, construction of roads and houses, mountain top removal, and hydraulic fracturing are threats to Wehrle's salamanders. No official conservation acts have been implemented to preserve Wehrle's salamander. However, the USDA recommended that landowners maintain montane oak, Quercus prinus , forests due to their association with Wehrle's salamander habitats.

Other Comments

Wehrle's salamanders were named by Fowler and Dunn of the Academy of Sciences after naturalist, R.W. Wehrle. He is credited with discovering the salamanders in the Two Licks Hills area of Indiana County, Pennsylvania in September 1911.

Additional Links

AmphibiaWeb

Encyclopedia of Life

Contributors

Hannah Reed (author), Radford University, Layne DiBuono (editor), Radford University, Lindsey Lee (editor), Radford University, Kioshi Lettsome (editor), Radford University, Karen Powers (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Altig, R., R. McDiarmid. 2015. Handbook of Larval Amphibians of the United States and Canada . Ithaca, New York: Cornell University Press.

Beane, J., A. Braswell, J. Mitchell, W. Palmer, J. Harrison. 2010. Amphibians and Reptiles of the Carolinas and Virginia . Chapel Hill, North Carolina: The University of North Carolina Press.

Beneski, J. 1989. Adaptive significance of tail autotomy in the salamander, Ensatina. Journal of Herpetology , 23/3: 322-324.

Bonett, R., A. Blair. 2017. Evidence for complex life cycle constraints on salamander body form diversification. Proceedings of the National Academy of Science of the United States of America , 114/37: 9936–9941.

Breisch, A. 2017. The Snake and the Salamander: Reptiles and Amphibians from Maine to Virginia . Baltimore, Maryland: John Hopkins University Press.

Buckles, J. 2013. "Indiana County Parks and Trails" (On-line). Accessed November 16, 2018 at https://www.indianacountyparks.org/flipbooks/r-w-wehrle-flipbook.aspx .

Dodd, C. 1989. Duration of immobility in salamanders, genus Plethodon (Caudata: Plethodontidae). Herpetologica , 45/4: 467-473.

Dodd, C., E. Brodie. 1976. Observations on the mental hedonic gland-cluster of eastern salamanders of the genus Plethodon. Chesapeake Science , 17: 129–131.

Duellman, W. 1999. Patterns of Distribution of Amphibians: A Global Perspective . Baltimore, Maryland: The Johns Hopkins University Press.

Fergus, C., A. Hansen. 2003. Wildlife of Pennsylvania and the Northeast . Mechanicsburg, Pennsylvania: Stackpole Books.

Gibbs, J., A. Breisch, P. Ducey, G. Johnson, J. Behler, R. Bothner. 2007. The Amphibians and Reptiles of New York State: Identification, Natural History, and Conservation . New York, New York: Oxford University Press.

Green, N., T. Pauley. 1987. Amphibians and Reptiles in West Virginia . Pittsburgh, Pennsylvania: University of Pittsburgh Press.

Hall, R., D. Stafford. 1972. Studies in the life history of Wehrle's salamanders, Plethodon wehrlei. Herpetologica , 28/4: 300-309.

Highton, R., A. Hastings-Picard, C. Palmer, R. Watts, C. Hass, M. Culver, S. Arnold. 2012. Concurrent speciation in the eastern woodland salamanders (genus Plethodon): DNA sequences of the complete albumin nuclear and partial mitochondrial 12s genes. Molecular Phylogenetics and Evolution , 63/2: 278-290.

IUCN SSC Amphibian Specialist Group, 2014. "Plethodon wehrlei" (On-line). The IUCN Red List of Threatened Species 2014: e.T59362A56286906. Accessed September 07, 2018 at http://dx.doi.org/10.2305/IUCN.UK.20141.RLTS.T59362A56286906.en .

Kerney, R. 2011. Embryonic staging table for a direct-developing salamander, Plethodon cinereus (Plethodontidae). The Anatomical Record , 294/11: 1796-1808.

Kiviat, E. 2013. Risks to biodiversity from hydraulic fracturing for natural gas in the Marcellus and Utica shales. Annalis of New York Academy of Science , 1286/1: 1-14.

Kuchta, S., A. Brown, R. Highton. 2018. Disintegrating over space and time: Paraphyly and species delimitation in the Wehrle’s salamander complex. Zoologica Scripta , 47: 285-299.

Lannoo, M. 2005. Amphibian Declines: The Conservation Status of United States Species . Los Angeles, California: University of California Press.

Marvin, G. 1996. Life history and population characteristics of the salamander Plethodon kentucki with a review of Plethodon life histories. The American Midland Naturalist , 136/2: 385-400.

McAllister, C., C. Bursey, H. Robison, M. Connior. 2013. Parasites of the ozark zig-zag salamander, Plethodon angusticlavius (Caudata: Plethodontidae), from northern Arkansas. Comparative Parasitology , 80/1: 69-79.

McAllister, C., C. Bursey. 2004. Endoparasites of the dark-sided salamander, Eurycea longicauda melanopleura, and the cave salamander, Eurycea lucifuga (Caudata: Plethodontidae), from two caves in Arkansas, U.S.A. Comparative Parasitology , 71/1: 61-66.

Mitchell, J., W. Gibbons. 2010. Salamanders of the Southeast . Athens, Georgia: University of Georgia Press.

Newman, W. 1954. A new Plethodontid salamander from southwestern Virginia. Herpetologica , 10/1: 9-14.

O'Donnell, K., R. Semlitsch. 2015. Advancing terrestrial salamander population ecology: The central role of imperfect detection. Journal of Herpetology , 49/3: 533-540.

Palmer, C., R. Watts, R. Gregg, S. Arnold. 2005. Lineage-specific differences in evolutionary mode in a salamander courtship pheromone. Molecular Biology and Evolution , 22/11: 2243-2256.

Pellitteri, P. 2007. "University of Wisconsin-Extension" (On-line pdf). Accessed November 16, 2018 at http://labs.russell.wisc.edu/insectid/files/2014/03/NuisanceWeevils.pdf .

Petranka, J. 2010. Salamanders of the United States and Canada . Washington, D.C.: The Smithsonian Institute.

Petty, J., G. Gingerich, J. Anderson, P. Ziemkiewicz. 2013. Ecological function of constructed perennial stream channels on reclaimed surface coal mines. Hydrobiologia , 720/1: 39–53.

Powders, V. 1970. ltitudinal distribution of the protozoan Cepedietta michiganesis in the salamanders Plethodon glutinosus and Plethodon jordani in eastern Tennessee. The American Midland Naturalist , 83/2: 393-403.

Powell, R., R. Conant, J. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America . Boston, New York: Houghton Mifflin Harcourt.

Server, D. 2016. Ultrastructure of the mental gland of the red‐backed salamander, Plethodon cinereus (Amphibia: Plethodontidae). Acta Zoological , 98/2: 154-162.

Snider, A., J. Bowler. 1992. Longevity of Reptiles and Amphibians in North American Collections, Second Edition . Oxford, Ohio: Society for the Study of Amphibians and Reptiles.

Staub, N. 2016. The age of Plethodontid salamanders: A short review on longevity. Copeia , 104/1: 118-123.

Wilson, L. 1995. The Land Manager's Guide to the Amphibians and Reptiles of the South . Chapel Hill, North Carolina: The Nature Conservancy, Southeastern Region.

United States Department of Agriculture Forest Service. Nantahala and Pisgah National Forests plan revision draft. 5436766. Washington, D.C.: USDAFS. 2013.