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Wildlife are faced with numerous threats to survival, none more pressing than that of climate change. Understanding how species will respond behaviorally, physiologically, and demographically to a changing climate is a cornerstone of many contemporary ecological studies, especially for organisms, such as amphibians, whose persistence is closely tied to abiotic conditions. Activity is a useful parameter for understanding the effects of climate change because activity is directly linked to fitness as it dictates foraging times, energy budgets, and mating opportunities. However, activity can be challenging to measure directly, especially for secretive organisms like plethodontid salamanders, which only become surface active when conditions are cool and moist because of their anatomical and physiological restrictions. We estimated abiotic predictors of surface activity for the seven species of the Plethodon jordani complex. Five independent data sets collected from 2004 to 2017 were used to determine the parameters driving salamander surface activity in the present day, which were then used to predict potential activity changes over the next 80 yrs. Average active seasonal temperature and vapor pressure deficit were the strongest predictors of salamander surface activity and, without physiological or behavioral modifications, salamanders were predicted to exhibit a higher probability of surface activity during peak active season under future climate conditions. Temperatures during the active season likely do not exceed salamander thermal maxima to cause activity suppression and, until physiological limits are reached, future conditions may continue to increase activity. Our model is the first comprehensive field-based study to assess current and future surface activity probability. Our study provides insights into how a key behavior driving fitness may be affected by climate change.

The size of an organism is perhaps its most overt physical characteristic, and variation in body size has long been of interest to biologists. Bergmann's rule has been actively studied and debated for more than 150 years. Despite this long history, the generality and applicability of Bergmann's rule to ectothermic organisms generally, and to plethodontid salamanders specifically, has resulted in an extensive and conflicting literature. Regardless of mechanism, clinal variation in body size has been widely observed in plethodontid salamanders and other ectothermic vertebrates. In this study, we assessed the change in adult body size of four plethodontid salamanders (Desmognathus imitator, D. ocoee, D. wrighti, and Plethodon jordani) across a 1,350 m elevational gradient in Great Smoky Mountains National Park. Using 1,293 observations of salamanders at 25 sites, we found clear and significant patterns of increasing adult body size with elevation in all four species. Average rates of increase ranged from 1.0...

Aim Approximately 32.5% of all amphibian species are globally threatened, and amphibian extinctions have been recorded worldwide. Individual studies rarely give full consideration to multiple potential drivers of observed biological change, instead tending to attribute changes to a single driver. Here, I tested for impacts of land use and climate change on range changes in a community of plethodontid salamanders living from 518 to 2036 m elevation in a global hotspot for amphibian diversity. Location The southern Appalachian Mountains. Methods I resurveyed 18 elevational transects that had originally been surveyed by Nelson Hairston in 1940, 1947 and 1949. I recorded range changes for nine species that Hairston studied and determined the extent to which the recorded expansions or contractions could be attributed to changes in forest stand, climate and competition, singly or in combination. Results ‘Montane’ species, which occur only on mountaintops, had expanded their lower elevational limits downwards. ‘Foothill’ species, which occur at lower elevations than montane species, had expanded their upper elevational limits upwards. Main conclusions For montane species these downward expansions appear to be the result of two processes: local cooling of the climate and maturation of forests after the cessation of large-scale logging operations c. 80 years ago. In contrast, changes in upper elevational range limits of foothill species are probably the result of a suite of complex and interacting drivers, including, but not limited to, maturation of forests, changes in climate, and interactions with other species.

Many animal and plant taxa reach their highest endemism and species richness in montane regions. The study of elevational range limits is central to understanding this widespread pattern and to predicting the responses of montane species to climate change. Yet, because large-scale manipulations of the distributions of most species are difficult, the causes of species’ elevational range limits (e.g. competitive interactions, physiological specialization) are poorly understood. Here, we harness the power of new mechanistic approaches to dissect the factors that underlie the elevational replacement of two salamander species in the Appalachian Highlands. Our results challenge the long-held idea that competitive interactions drive the lower elevational range limits of montane species and that physiological stress prevents low-elevation species from expanding to high elevations. We show that physiological constraints drive the lower elevational range limit of the montane-endemic species, Plethodon jordani. Conversely, we find that competition with P. jordani prevents the low-elevation species, P. teyahalee, from expanding its range to include higher-elevation habitats. These results are broadly consistent with the biogeography and behavior of other montane species, suggesting that similar mechanisms underlie patterns of elevational zonation across a variety of taxa and montane regions. To the extent that our findings are taxonomically and geographically widespread, these results challenge the idea that competitive release at species’ lower elevational range limits is driving the downslope range shifts exhibit by some montane taxa. Instead, our results raise the sobering possibility that even small changes in climate might cause erosion of the ranges of many high-elevation species.

Summary 1. Over the last 30 years there has been a great deal of interest in investigating patterns of species co-occurrence across a number of locations, which has led to the development of numerous methods to determine whether there is evidence that a particular pattern may not have occurred by random chance. 2. A key aspect that seems to have been largely overlooked is the possibility that species may not always be detected at a location when present, which leads to ‘false absences’ in a species presence/absence matrix that may cause incorrect inferences to be made about co-occurrence patterns. Furthermore, many of the published methods for investigating patterns of species co-occurrence do not account for potential differences in the site characteristics that may partially (at least) explain non-random patterns (e.g. due to species having similar/different habitat preferences). 3. Here we present a statistical method for modelling co-occurrence patterns between species while accounting for imperfect detection and site characteristics. This method requires that multiple presence/absence surveys for the species be conducted over a reasonably short period of time at most sites. The method yields unbiased estimates of probabilities of occurrence, and is practical when the number of species is small ( < 4). 4. To illustrate the method we consider data collected on two terrestrial salamander species, Plethodon jordani and members of the Plethodon glutinosus complex, collected in the Great Smoky Mountains National Park, USA. We find no evidence that the species do not occur independently at sites once site elevation has been allowed for, although we find some evidence of a statistical interaction between species in terms of detectability that we suggest may be due to changes in relative abundances.

All animals and plants have intimate associations with microbes. Opinion has shifted from viewing microbes primarily as pathogens to the idea that healthy animals and plants carry specialized communities of coevolving microorganisms. However, the generality of this proposition is unknown because surveys rarely compare host-associated microbes with samples from relevant microhabitats. Symbiotic communities might be assembled from local environments with little evolutionary specialization. We evaluated the specificity of bacteria associated with salamander skin in comparison with surfaces in their immediate environments using 16S rRNA sequences. Host-associated and free-living samples were significantly different. However, relative abundances were strongly correlated; the most abundant taxa on salamander skin were also most abundant on moist debris on the forest floor. Thus, although bacterial assemblages on salamander skin are statistically differentiated from those on inanimate surfaces, they are not entirely ‘distinct’. Candidate salamander specialists were few in number and occurred at low relative abundances. Within some OTUs, differences in allele frequency suggested genetic specialization at finer levels. Although host-associated and free-living assemblages were similar, a range of more or less specialized symbiotes was evident and bacteria on salamander skin were often specific genotypes of OTUs commonly found on other moist surfaces in the environment.

Behavioral interactions with native species may influence the invasiveness of introduced species. The salamanders Plethodon glutinosus and P. jordani in the eastern United States share many life history traits and demonstrate complex interspecific interactions that range geographically from competitive exclusion to sympatry. P. jordani was introduced to Mountain Lake Biological Station, Virginia, USA, between the years 1935 and 1945. We tested whether competition for space may influence the invasion of P. jordani into native P. glutinosus habitat by utilizing data from natural distributions, a field experiment, and controlled laboratory experiments. No environmental variables differed where P. glutinosus and P. jordani were collected in the field at the site of P. jordani introduction. In the field experiment, P. glutinosus was more fully exposed during foraging bouts in cages shared with heterospecifics as opposed to ones shared with conspecific salamanders. Condition (mass relative to body length) of salamanders at the end of the 3 months did not differ between conspecific and heterospecific treatments. In the laboratory, P. glutinosus most often attained the single burrow in the arena, but residency status had no effect. Species cohabited the burrow 50% of the time. Pair-wise encounters in the laboratory indicated that both species spend less than 20% of the time in aggressive behaviors as juveniles. Adults showed no behavior interpreted by us as aggression during pair-wise encounters.

We examined intraand interspecific chemical variation in salamander courtship pheromones. The extent to which plethodontid receptivity factor (PRF) and other glandular components vary among populations of Plethodon jordani was analyzed by reverse-phase HPLC. Gland extracts from individuals revealed that males within a population differ in the relative amounts of the glandular components as well as in the presence and absence of components, including PRF. Comparisons between populations showed that each population had a unique elution profile and differed significantly in the relative amounts of PRF and the other extract components. Knowledge about the nature of geographic variation in the courtship pheromone, combined with behavioral tests of female response, will contribute towards understanding how the pheromone evolved.

As part of the Wine Spring Creek ecosystem management project on the Nantahala National forest, North Carolina, we assessed effects of a community restoration fire on small mammals and herpetofauna in the upper slope pitch pine (Pinus rigida) stands, neighboring midslope oak (Quercus spp.) stands and rhododendron (Rhododendron maximum) dominated riparian areas during 1995 and 1996. Using drift-fence arrays with pitfalls and snap-trapping, we collected these small mammals: masked shrew (Sorex cinereus), smoky shrew (S. fumeus), water shrew (S. palustris), pygmy shrew (S. hoyi), northern short-tailed shrew (Blarina brevicauda), deer mouse (Peromyscus maniculatus), white-footed mouse (P. leucopus), golden mouse (Ochrotomys nuttalli), southern red-backed vole (Clethrionomys gapperi), pine vole (Microtus pinetorum) and woodland jumping mouse (Napaeozapus insignis). Herpetofauna collected from drift-fence arrays and time-constrained searches included: eastern newt (Notophtalmus viridescens), seepage salamander (Desmognathus aeneus), mountain dusky salamander (D. ochrophaeus), Blue Ridge two-lined salamander (Eurycea wilderae), spring salamander (Gyrinophilus porphyriticus), Jordan’s salamander (Plethodon jordani), wood frog (Rana sylvatica), five-lined skink (Eumeces fasciatus), eastern garter snake (Thamnophis sirtalis), and northern ringneck snake (Diadophis punctatus). Prior to the prescribed community restoration fire in the spring of 1995, there were no significant differences in small mammal or herpetofauna collections between burned and control areas. Post-treatment in 1995 and 1996, showed no significant differences among collections of most species between burned and control areas. Slope position accounted for more variation among the species of greatest abundance than did burning. Concern for the effects of prescribed fire as a management tool on small mammals and herpetofauna in the southern Appalachians seems unwarranted. # 1999 Elsevier Science B.V. All rights reserved.

The disappearance and return of plethodontid salamanders on clearcuts has been monitored since 1979 in the southern Blue Ridge Mountains at three sites near Highlands, North Carolina. Salamander abundance on 225 m2 plots located on clearcuts and in nearby forest was determined by nightly non-destructive searches. Abundances on clearcut and forest plots at a given site were compared for each year in which sampling occurred. Numbers of salamanders on clearcut plots decreased to 30–50% of forested plots in the first year after logging and were almost zero by the second year. Decreases in standing crop and moisture content of leaf litter seem responsible for salamander disappearance. Salamanders returned to clearcuts 4–6 years after cutting, and their numbers increased rapidly. Linear regressions estimate that salamander numbers on clearcut plots will equal or exceed numbers on forested plots by 20–24 years after cutting. The pattern of salamander return to clearcuts appears closely correlated with the timing of litter layer reformation. All sex and age classes of the most common species, Plethodon jordani, disappear from clearcuts at equal rates, whereas the earliest colonizers are predominantly large adults. Plethodon oconaluftee, a desiccation-resistant species, exists on regenerating clearcuts in disproportionately large numbers. Large adults of all species, including Plethodon oconaluftee, may be better able to withstand the drier, sparse litter cover of young, regenerating stands. Adults might move to clearcuts to avoid competition from smaller and immature salamanders restricted to mature forests with abundant, moist litter. La desaparicion y retorno de salamandras pletodontidas en areas de tala extrema han sido monitoreadas desde 1979 en las montanas Blue Ridge del Sur, en tres sitios de los alrededores de Highlands, Carolina del Norte. La abundancia de las salamandras en areas de 225 m2 localizados en zonas taladas y en bosques cercanos se determino mediante busquedas nocturnas no destructivas. La abundancia en las areas de zonas taladas y bosques en un sitio determinado fueron comparadas para cada ano muestreado. El numero de salamandras en areas taladas disminuyo en un 30–50% con respecto a las areas boscosas en el primer ano posterior a la tala y fue de casi cero el segundo ano. Disminuciones en la cosecha sostenida y contenido de humedad en detritus de hojas parecen ser los responsables de la desaparicion. Las salamandras retornaron a las areas taladas 4–5 anos despues de la tala y sus numeros incrementaron rapidamente. Regresiones lineales estiman que el numero de salamandras en areas taladas igualara o excedera el numero en las areas boscosas en 20–24 anos despues de la tala. El patron de retorno parece estar fuertemente correlacionado con el tiempo de reconstruccion de la capa de detritus. Todas las clases de edades y sexos de la especie mas comun, Plethodon jordani, desaparecieron de las areas taladas a tasas iguales, mientras que los primeros colonizadores son predominantemente adultos. Plethodon oconaluftee una especie resistente a la desecacion, existe en areas de regeneracion en numeros desproporcionadamente grandes. Adultos grandes de todas las especies, incluyendo Plethodon oconaluftee, pueden ser mas aptos para soportar la cobertura de detritus seco y disperso de zonas en regeneracion. Los adultos podrian haberse movido para evitar la competencia con salamandras mas pequenas e inmaduras restringidas a bosques maduros con abundante detritus humedo.

In salamanders of the species Salamandra salamandra, Pleurodeles waltl , and Plethodon jordani , tectal efferent neurons projecting to the bulbar reticular formation show a stereotyped distribution as revealed by the horseradish peroxidase (HRP) method. The density of these cells increases toward caudal tectal levels reaching its maximum at the isthmic region. Neurons with ipsilaterally descending axons constitute 60–87% and are concentrated in the dorsomedial and ventrolateral sector of the tectal hemisphere, with only few neurons in the intermediate part. The contralaterally descending neurons are concentrated in the lateral sector. This pattern is assumed to reflect a motor map in the coordinates of the salamander neck muscle system.

Four species of salamander of the family Plethodontidae were examined using electromyographic (EMG) recording during prey-capture behavior to test the hypotheses that the tongue retractor, tongue protractor and jaw depressor muscles are activated simultaneously and in a stereotyped pattern, as was found in other salamanders, and to determine whether species with different tongue morphologies and tongue protraction abilities exhibit different motor control strategies. The results show that sequential activation was observed far more frequently than simultaneous activation; the jaw depressor muscle was activated first, followed by the tongue protractor and then the tongue retractor. Species with short, attached tongues (Desmognathus quadramaculatus and Plethodon jordani) showed simultaneous activation more often than species with long, free tongues (Pseudotriton ruber and Hydromantes supramontis), which showed strongly non-simultaneous activation. Most EMG variables showed no effect of prey-capture success, suggesting that sensory feedback is not involved in modulating the motor pattern during the prey-capture strike. Hydromantes supramontis was examined for modulation of its motor pattern in response to prey distance, and several EMG variables were found to be positively correlated with tongue protraction distance. The motor pattern of strongly non-simultaneous activation of antagonistic tongue muscles has evolved along with the evolution of long, free tongues in plethodontids. The variable motor patterns observed provide further evidence that amphibian feeding in general is not as highly stereotyped as has been previously thought.

We analyzed extracts from specialized male glands that are hypertrophied only during the courtship season in the terrestrial salamander Plethodon jordani (Plethodontidae). Protein analysis and gel electrophoresis revealed approximately 20 bands of protein components (as separated by molecular weight), many of which were glycoproteins. Analyses by high performance liquid chromatography and amino acid sequencing reveal that approximately 85% of the pheromone protein extract was accounted for by two components (and their isoforms). These components were termed Pj-22 and Pj-10 to reflect their respective molecular weights of approximately 22 kDa and 10 kDa. The chemical nature of Pj-22 fits the profile for odorants (known from other vertebrates) that stimulate the vomeronasal organ and can ultimately affect reproductive behavior. Our data are considered in the context of separate behavioral experiments with P. jordani that indicated: (a) delivery of pooled gland extracts resulted in increased female receptivity, and (b) an enriched solution of Pj-22 also was effective at increasing female receptivity.

Experimental removal of the terrestrial salamander Plethodon jordani from marked plots in the Great Smoky Mountains and the Balsam Mountains of North Carolina, USA resulted in statistically significant increases in the abundance of P. glutinosus in both areas. The increase ap- peared earlier in the Smokies, where the two species overlap by only 70-120 m. Removal of P. glutinosus, the less abundant species, did not result in a statistically significant increase in P. jordani, but did increase the proportion of young in that species. Again, the effect was more pronounced in the Smokies than in the Balsams, where the altitudinal overlap is 1220 m (4000 ft). Stronger compe- tition in the narrow zone of overlap had been predicted on the basis of field distributions, but a measurable level of competition in the wide zone of overlap was surprising. The experiments permitted the direct calculation of coefficients of competition and carrying capacities for both species in both areas. Competition coefficients were higher in the Smokies, but carrying capacities were very similar in the two areas. The experimental approach eliminated the assumptions required for calculating competition coefficients by resource partitioning, and since the experimental design was published before the experiments were begun, the circularity implicit in retrospective analyses was avoided.

This research analyses variation in the interspecific aggressive behaviour of two salamander species, Plethodon jordani and P. glutinosus , from three localities which differ in extent of sympatry, the intensity of interspecific competition and frequency of hybridization. If interspecific aggression evolved by misidentification of species, it should either (1) vary concordantly with the frequency of hybridization, or (2) be similar in all of the localities. If selection for interspecific interference has occurred, interspecific aggression should vary concordantly with interspecific competition. Misidentification can account for variation in the interspecific aggressive behaviour of P. glutinosus, P. glutinosus from all localities did not distinguish behaviourally between heterospecifics and conspecifics. In contrast, for P. jordani , results suggest that alpha-selection has occurred under conditions of strong interspecific competition. P. jordani from the locality where interspecific competition is weak were less aggressive to heterospecifics than to conspecifics, while P. jordani from two localities where interspecific competition is strong were equally aggressive to heterospecifics and conspecifics.

The effects of competition on the evolution of interspecific interference mechanisms were studied by comparing the aggressive behavior of two terrestrial salamander species from two localities that differ in the intensity of interspecific competition. Plethodon jordani and P. glutinosus are closely related, ecologically similar species that are sympatric at intermediate elevations in the southern Appalachian Mountains. Previous removal and transplant experiments showed that interspecific competition is more intense in the northeastern Great Smoky Mountains, where the species are narrowly sympatric, than in the nearby Balsam Mountains, where sympatry is broader. In laboratory encounters, P. glutinosus from the Great Smoky Mountains were more aggressive to heterospecific and conspecific intruders than were P. glutinosus from the Balsam Mountains. For P. jordani, however, the variation in interspecific and intraspecific aggressive behavior among individuals within populations was as great as the variation between populations. Alpha-selection (i.e., improved competitive ability by the acquisition of interspecific interference mechanisms) has occurred in populations of P. glutinosus under conditions of intense interspecific competition. The evolution of aggressive behavior appears to have been influenced by the intensity of intraspecific competition as well.

1. We staged predatory encounters between snakes and salamanders in the laboratory. 2. Both snakes and salamanders accumulated significant quantities of lactic acid (0.3–2.3 mg/g) during predatory encounters. In a typical 14.4 min encounter, lactate concentration reached 260% of resting levels in snake predators and 880% of resting levels in salamander prey. This is one of the first demonstrations of anaerobiosis during natural ‘burst’ activity in both predator and prey. 3. Salamander responses to snake attack were surprisingly variable, and included writhing, thrashing, tail wrapping, tail autotomy, and biting. Antipredator responses were effective in nearly one third of trials. Lactate concentration was significantly correlated with duration of predatory encounters (r=0.57), snake mass, and salamander mass (Table 3). 4. Our calculations suggest that attack and ingestion of prey may cost snakes less than 1% of energy assimilated from prey.

Using museum collection records and variables computed by digital terrain modeling in a geographic information system, we examined the relationship of elevation, aspect, and “cove” patch size to the presence or absence of 7 common woodland salamanders in mature cove hardwood and northern hardwood forests in the southern Appalachians of Georgia, North Carolina, and South Carolina. Overall, elevation, aspect and patch size were poor discriminators among salamander species presence or absence at collection sites. Increased elevation was an important variable explaining the presence of Ocoee salamanders (Desmognathus ocoee) and Jordan's salamanders (Plethodon jordani). In contrast, decreased elevation was an important variable explaining the presence of slimy salamanders (Plethodon glutinosus). Our study contrasts with recent research indicating that suitable habitat patch size is an important determinant of woodland salamander species richness and abundance at recently disturbed sites. In these matu...

Plethodon jordani and P. teyahalee are terrestrial salamanders sympatric at various localities within the Great Smoky Mountains. These two species hybridize in some localities but not in others. Species from hybridizing and non-hybridizing localities were tested in an olfactometer for the ability to distinguish between odors of opposite sex conspecifics and heterospecifics. Male P. jordani and P. teyahalee from the non-hybridizing locality preferred conspecific odors over heterospecific odors, but only male P. teyahalee from the hybridizing locality showed a preference, preferring conspecific odors. Only female P. teyahalee from the non-hybridizing locality showed a significant preference between male odors, preferring heterospecifics. Previous tests had shown that female odor preferences are influenced by their breeding status, and blank tests (no salamander odor vs salamander odor) can be used to determine whether females are attracted to or repelled by male odors. Females of both species from the non-hybridizing locality preferred the blank over conspecific male odors. These results suggest that chemoreception may function as a reproductive isolating mechanism at the non-hybridizing locality. However, at the hybridizing locality only male P. teyahalee appear to be able to discriminate between species odors, suggesting that the lack of an ability to discriminate between species by means of chemical cues may account for the lack of reproductive isolation at this locality.

GRANT, D., 0. ANDERSON, AND V. TWITTY. 1968. Homing orientation by olfaction in newts (Taricha rivularis). Science 160:1354-1356. HAYNE, D. W. 1949. Calculation of size of home range. J. Mammal. 30:1-18. HUHEEY, J. E., AND R. A. BRANDON. 1973. Rockface populations of the mountain salamander, Desmognathus ochrophaeus, in North Carolina. Ecol. Monogr. 43:59-77. KLEEBERGER, S. R., AND J. K. WERNER. 1982. Home range and homing behavior of _ethodon cinereus in northern Michigan. Copeia 1982:In press. MADISON, D. M. 1969. Homing behavior of the red-cheeked salamander, Plethodon jordani. Anim. Behav. 17:25-39.

Four spermatophore cap microstructures were observed among 10 species of salamander: 1) In five species of Ambystoma the central area of the cap was surrounded by a membrane-like structure that was distorted by the top of the stalk. This central area contained fibrous material, free cytoplasmic droplets and tail ends of spermatozoa. On the periphery of the cap spermatozoa were aligned in groups with heads directed outward and tails inward. 2) In Notophthalmus viridescens, Cynops pyrrhogaster and Triturus vulgaris the central area containing fibrous material and free cytoplasmic droplets was also limited by a membranelike structure which, however, did not reflect the contour of the top of the stalk. In N. viridescens spermatozoa also were concentrated at the cap periphery but in coiled groups with heads and tails in register, heads directed inward. In C. pyrrhogaster and T. vulgaris spermatozoa were distributed randomly throughout the cap. 3) In Pleurodeles waltl there was no membrane-like structure in the cap; however, spermatozoa arranged randomly throughout the cap were less abundant or absent in the central region, which contained fibrous material and cytoplasmic droplets. 4) In Plethodon jordani the cap consisted of an outer, mucus-covered opaque capsule enclosing two inner granular layers and spermatozoa on the under surface of the cap, against the top of the stalk. Masses of spermatozoa were aligned with heads directed toward the stalk and tails extended into the

The oxygen consumption and total body lactate concentration of specimens of the terrestrial salamander Plethodon jordani were measured at rest and after 5 min of forced locomotion, at full hydration (100% of standard body mass) and after dehydration to 85% of standard mass, at 15 and 25?C. In addition, we measured standard and activity oxygen consumption of specimens of newts, Notophthalmus viridescens, in their terrestrial stage (efts), at 100% and 80% of standard mass, at 15?C. Dehydration had no effect on the oxygen consumption of these salamanders at rest or during induced activity. Furthermore, dehydration elicited no change in the resting or post-activity lactate concentration. The reduction in voluntary foraging activity by terrestrial salamanders during dry periods cannot be attributed to a dehydration induced loss in the capacity to power locomotion by aerobic or anaerobic means.

The complex of red-legged Plethodon jordani (model) and red-legged (mimic) and non-red-legged (non-mimic) Desmognathus ochrophaeus appears to be a weak Batesian mimetic system. Experimental predators (chickens) showed neither increased avoidance nor increased attack latency in single salamander presentations of models and non-mimics. In choice presentations of non-mimics with models or mimics, however, some chickens showed reduced preference for both models and mimics compared to non-mimics.

erythronotus (Green). Biol. Bull., 20(6):332-49. HIGHTON, R. 1956. The life history of the Slimy salamander, Plethodon glutinosus in Florida. Copeia, 1956 (2):75-93. NOBLE, G. K. AND M. K. BRADY. 1930. The tail and compared o hat of Plethodon ani metcalfi and Plethodon glutinosus. rting males do not distinguish b tween e sexes but sex recognition is accomplished behavioral responses on the par of the la ander being approached. Aggr ssive shes develop between males bu not becourtship of the plethodontid salamanders. Copeia, 1930 (2):52-4. ORGAN, J. A. 1958. Courtship and spermatophore of Plethodon jordani metcalfi. Copeia, 1958 (4):251-59. . 1960. The courtship and spermatophore of the salamander Plethodon glutinosus. Copeia, 1960 (1):34-40. PIERSOL, W. H. 1910. The habits and larval state of Plethodon cinereus erythronotus. Trans. Can. Inst., 8:469-93. . 1914. The egg laying habits of Plethodon cinereus. Trans. Royal Can. Inst., 10: 12126.

The supposed mimetic complex consisting of the red- cheeked salamander, Plethodon jordani, and the red-cheeked variants of the Allegheny Mountain salamander, Desmognathus ochrophaeus, was tested by subjecting members of this complex to laboratory predation by four natural predator species. Predation by the eastern garter snake, the large short-tailed shrew, the Blue Ridge spring salamander, and the black-bellied salamander failed to reveal discriminatory feeding behavior. The possibility that mimicry has not been involved in the evolution of the red cheek patch in D. ochrophaeus remains. The hypothesis that infrequent but discriminate predation by uncommon predators such as birds could confer slight selective advantage upon the D. ochrophaeus the range of red-cheeked P. jordani the incidence of the red cheek coloration among normally patterned D. ochrophaeus is low. Numerous individuals have suggested that the similarity can be best explained in terms of mimicry. According to the theory of Bate- sian mimicry, the red cheek patch of P. jordani (the model) could be considered warning or aposematic coloration, which would "ad- vertise" to, predators some distasteful or undesirable quality. Huheey (1960) suggests that this undesirable characteristic is a slimy exuda- tion from the tail, not found in D. ochrophaeus. The red-cheeked variant of D. ochrophaeus (the mimic), which exhibits pseudapose- matic or false warning coloration, would thus gain survival value from its close resemblance to the model, even though it possessed none of the undesirable qualities. In Miillerian mimicry, both P. jordani and the red-cheeked D. ochrophaeus would possess unde- sirable qualities and thus the model and the mimic are both protected by undesirable characteristics. In the study of any suspected mimicry complex, the determina- tion of a natural predator that discriminates between the supposed mimics and nonmimetics is of utmost importance. If one can ascer- tain the natural predators of the models and mimics by field obser- vations or stomach analyses, and then prove the discriminating behavior of at least one such predator, he greatly strengthens the hypothesis 147

GASCO, F. 1881. Les amours des axolotls. Zool. Anzeiger 4:313-316, 328-334. KNUDSEN, J. W. 1960. The courtship and egg mass of Ambystoma gracile and Ambystoma macrodactylum. Copeia 1960:44-46. KUMPF, K. F., AND S. C. YEATON. 1932. Observations on the courtship behavior of Ambystoma jeffersonianum. Am. Mus. Novitates No. 546:7 p. MOHR, C. E. 1931. Observations on the early breeding habits of Ambystoma jeffersonianum in central Pennsylvania. Copeia 1931:102-104. NOBLE, G. K. 1931. The biology of the amphibia. New York and London: McGraw Hill, xiii, 577 p. lasping behavior f these two specie is conidered as derived from the more primitive attern known for most ther members of the AND M. K. BRADY. 1933. Observations on the life history of the Marbled Salamander, Ambystoma opacum Gravenhorst. Zoologica 11:89-132. ORGAN, J. A. 1958. Courtship and spermatophore of Plethodon jordani metcalfi. Copeia 1958:251-259. 1960. The courtship and spermatophore of the salamander, Plethodon glutinosus. Copeia 1960:34-40. RUSSELL, R. W., AND J. D. ANDERSON. 1956. A disjunct population of the long-toed salamander from the coast of California. Herpetologica 12:137-140. SLATER, J. R. 1936. Notes on Ambystoma gracile Baird and Ambystoma macrodactylum Baird. Copeia 1936:234-236. SMITH, R. E. 1941. Mating behavior in Triturus torosus and related newts. Copeia 19/1: 255-262.

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During 1966 and 1967, 392 Plethodon glutinosus and 988 P. jordani, collected in the Great Smoky Mountains National Park and Knox County, Tennessee, were examined for the intestinal ciliate, Cepedietta michiganensis. There was no difference in infection rate between the two salamander species at comparable altitudes. Infection rates were inversely proportional to altitude and infections are apparently limited to altitudes below 1400 m. Infection rates were significantly lower in spring than in autumn and this was attributed to winter extremes of temperature. The possible role of various factors which might affect per cent infection and altitudinal distribution of C. michiganensis is discussed. It is suggested that temperature, directly or indirectly, is the major factor that controls and/or limits the vertical distribution of C. michiganensis.