User:Natedavino/Red-backed salamander

SANDBOX DRAFT OF RED-BACKED SALAMANDER ARTICLE

Copy-pasted Lead [my additions bracketed]:

The red-backed salamander (Plethodon cinereus) is a small, hardy woodland salamander species in the family Plethodontidae. The species inhabits wooded slopes in eastern North America, west to Missouri, south to North Carolina, and north from southern Quebec and the Maritime provinces in Canada to Minnesota. It is also known as the redback salamander, eastern red-backed salamander, or the northern red-backed salamander to distinguish it from the southern red-backed salamander (Plethodon serratus). It is one of 56 species in the genus Plethodon. [Red-backed salamanders are notable for their color polymorphism and primarily display two color morph varieties ("red-backed" and "lead-backed"), which potentially differ in physiology and anti-predator behavior. ].

New material:

As with all amphibians, the red-backed salamander has permeable skin. They also lack lungs, a condition which is an ancestral trait of the Plethodontidae. Red-backed salamanders are thus entirely reliant on cutaneous respiration for gas exchange. Permeable skin is susceptible to desiccation and must be kept moist in order to facilitate cutaneous respiration; as a result much of the ecology and behavior of the red-backed salamander is restricted by climatic and microclimatic variables, particularly dryness and temperature. Individuals confine themselves to moist microhabitats (beneath rocks, woody debris, etc. as well as beneath the soil) for long periods of time in order to maintain hydration when surface conditions are inhospitably dry or hot, and are only active on the surface to travel, forage, or reproduce for short periods. The duration of surface activity is directly limited by the rate of cutaneous water loss to the environment, which is influenced by environmental variables such as altitude, forest canopy cover, and the amount of recent precipitation. Hydric limitations are thus a major constraint on red-backed salamander growth and reproductive success as well as the genetic interconnectedness of red-backed salamander populations.

^^^notes: intended for 'Description and ecology' section. I feel like a lot of this might be better suited for the Plethodon or Plethodontidae pages, but I'll keep it here for now. Two of my citations are actually studies on a different species, Plethodon albagula, but literature on P. cinereus has cited them so I think it should be fine maybe. If not, all the more reason to throw this stuff into one of the genus or family pages. Also not sure if linking "genetic interconnectedness" to the Population Genetics article is called for.

Red-backed salamanders are mostly insectivorous, but prey on a wide assortment of other small invertebrates including isopods, millipedes, centipedes, pseudoscorpions, harvestmen, spiders, and gastropods. On one occasion an individual was found to have cannibalized a P. cinereus embryo. Predators of the red-backed salamander are many and varied, and include small mammals, snakes, ground-foraging birds, and larger salamanders.

^^^notes: intended for 'Description and ecology' section, potentially under a 'Diet and predators' section. Small and not very deep, but it seemed like a bad omission from the original article.

P. cinereus color morph frequencies are correlated with climatic variables, suggesting habitat temperature and more broadly climate to be potential sources of selective pressure on P. cinereus polymorphism. The red-backed form is found with greater frequency in colder regions at more northerly latitudes and easterly longitudes throughout its range, whereas the opposite is true of the lead-backed form. Additionally, lead-backed morphs withdraw from surface activity earlier in the autumn than red-backed morphs, presumably to avoid cooling temperatures. Standard metabolic rate has also been found to differ between the morphs at certain temperatures, with significantly lower metabolic rates being displayed by the lead-backed form at 15°C ; in the same study, lead-backed individuals were also more active on the ground surface at this temperature. These findings suggest that the lead-backed color variant is less tolerant of cool temperatures than the red-backed color variant, and that the two color forms differ physiologically and behaviorally at certain temperatures.

An alternate explanation for the uneven geographic distribution of the red-backed and lead-backed P. cinereus color morphs involves phenotypic plasticity responding to developmental temperature. Although the genetic origins of the P. cinereus polymorphic condition are not fully understood, initial studies indicate that color morph dominance is likely subject to epistasis, and that multiple loci may interact to determine an individual's morph condition. However, more recent research indicates that a plastic response to thermal conditions during development also contributes to color morph determination; in one study, P. cinereus eggs incubated at a higher temperature hatched a greater proportion of lead-backed morphs than eggs incubated at a lower temperature. Temperature-dependent color morph determination may therefore also potentially influence the spatial distribution of P. cinereus color morphs.

The two primary P. cinereus color morphs also differ in diet and susceptibility to certain diseases. The prevalence of certain prey taxa and the overall diversity and quality of prey items have been observed to differ seasonally between the two morphs in the spring and autumn when surface activity is greatest. In one study, the autumn diet of red-backed morphs was more diverse and of higher quality, and found to be dominated by mites, springtails, and ants, whereas the most important prey for lead-backed morphs were ants, mites, and isopods. NOT FINISHED

^^^notes: intended for 'Description and ecology' section (thinking about making a 'Polymorphism' subsection if I get enough other material in there). There's some more info on differences in diet and mating tendencies between the morphs in some papers I found, may add that later.

^note for the notes: I guess it goes way deeper with the polymorphism question. Lots of theories as to why they're polymorphic and what factors influence that. the significance of climate is disputed; it's not disproven as an aspect of it, but it's under a little fire lately. I plan to keep it but put in several other theories.