Plethodon kentucki

Abstract: To investigate the possible influence of variation in ecological and demographic factors on the spatial organization of the terrestrial plethodontid salamander Plethodon kentucki, I conducted a 3-year capture-recapture study and determined home-range characteristics and spatial relationships of individuals at two field sites that differed in predominant cover type and population density. Home ranges of adults were fixed and the home ranges of same-sex adult neighbors were mostly exclusive. The spatial arrangement of adult home ranges exhibited overall regularity or regularity within aggregations, whereas the distribution of juvenile home ranges was usually random. Analysis of nearest-neighbor sex indicated a positive intersexual association of adult home ranges. Removal studies provided evidence for defense of adult home ranges only at the high-density site. The distribution of home ranges was influenced by the presence of cover objects, but there was no significant relationship between adult body size and percent of home-range area with cover. Males overlapped the home ranges of gravid females significantly more often than those of non-gravid females, indicating that the distribution of gravid females had a strong influence on the distribution of male home ranges. In laboratory tests, increased male-male aggression during the breeding season suggests that males may compete for access to mates. At the high-density site, larger males may have benefited by having greater reproductive success than smaller males because they were more dominant and their home ranges overlapped a greater number of gravid-female home ranges. My results indicate that habitat structure and population density may influence the spatial organization and mating system of P. kentucki.

Abstract: Based on mark-recapture data collected over seven years on the salamander Plethodon kentucki, I examined (1) longevity and long-term site fidelity, (2) growth curves for each sex derived from both cross-sectional and longitudinal data on body size, (3) whether growth curves generated from the two kinds of data were comparable, and (4) how the relationship between adult body size and age in this species compares to that in other plethodontid salamanders. Recapture rates indicate that about 86% of males and 82% of females survived and remained in the study area from one year to the next. Most individuals recaptured at the end of the study period were within, or less than 2 m from, the home range they occupied at the beginning. Maximum age estimates were 13 yr for males and 16 yr for females. Growth curves derived from cross-sectional and longitudinal data were very similar. For both sexes, there is rapid growth up to the time of first reproduction (about 4 and 5 yr for males and females, respective...

Abstract: Competitive interactions among widely sympatric species of terrestrial plethodontid salamanders have received little attention. I investigated whether interspecific interference competition for space occurs between one such pair of species, Plethodon kentucki and P. glutinosus. Encounters between heterospecific adults in the laboratory resulted in aggressive interactions as often as did encounters between conspecific adults. However, intense aggression (bite-holds) occurred more often during pairings between conspecifics, indicating that interference competition is greater among individuals of the same species. Plethodon glutinosus was dominant more often than P. kentucki during encounters with heterospecifics in the laboratory. During a second laboratory experiment, both species preferentially used large cover sites in single-species control groups, whereas P. kentucki used small cover sites significantly more often in mixed-species experimental groups, indicating competitive exclusion of P. kentucki by ...

Abstract: To determine life history and population characteristics of the Cumberland Plateau woodland salamander (Plethodon kentucki), I conducted a three-yr mark-recapture study on two 225-M2 plots in southeastern Kentucky. I also observed egg clutches deposited by three captive females in the field and laboratory. Individual females reproduced biennially or less frequently; males bred annually. Mean clutch size was 10, and eggs were deposited in July and hatched during October. Hatchlings were 14 to 15 mm snout-vent length (SVL), and average growth was ca. 15, 10 and 6 mm SVL during the 1st, 2nd and 3rd yr of life aboveground. Thereafter growth continued to decline steadily with increasing body size. Growth rate of 2-yr-old juveniles varied significantly among years. Males reached sexual ma- turity at ca. 48 mm SVL (3-4 yr after hatching). Females began depositing eggs at about 52 mm SVL (probably 4-5 yr after hatching). Mean SVL for adult females (56.6 mm) was significantly greater than for adult males (54.1 mm). Jolly-Seber estimates of annual adult survival rate ranged from 0.72 to 0.91. Recapture rates among years showed that 2- and 3-yr- old juveniles had an annual survival rate of at least 0.48 and 0.68, respectively. Some micro- habitats supported significantly higher population densities than others, and densities varied little from year to year. Overall adult sex ratios were around 1:1 or significantly biased toward females, whereas the ratio of males to gravid females was significantly biased toward males in some years. Variation in life history and population characteristics between localities and years demonstrates the necessity of long-term studies on different populations when describ- ing salamander life histories.

Abstract: Complete catalogs of courtship behavior are available for only seven of the 42 currently recognized species of Plethodon. Additional detailed studies of courtship behavior in Plethodon species are needed to analyze the evolution of courtship behavior in this genus. We investigated the courtship behavior of the Cumberland Plateau woodland salamander (Plethodon kentucki) and compared it to previous accounts of courtship in other Plethodon species. In the laboratory, we videotaped the complete courtship of 30 different P. kentucki pairs, which included 46 tail-straddling walks that resulted in spermatophore deposition. From a transition matrix of observed motor patterns, we constructed a flow diagram of significant motor-pattern transitions during courtship. In general, the courtship behavior of this species is very similar to that of other large eastern Plethodon; however, there are some notable differences. Prior to the tail-straddling walk, the male transfers courtship pheromone from his mental gland to the female's nasolabial grooves (via mental-gland tapping and ‘chin-to-chin’ behavior patterns) more frequently than in other Plethodon. In most courtships, the female initiates contact leading to the tail-straddling walk. Males exhibit a greater propensity to deposit multiple spermatophores per courtship (two deposited in 33% of courtships, three deposited in 10% of courtships, X = 1.53 spermatophores per courtship) than males of other plethodontids. Mean size of the spermatophore is smaller than in other large eastern Plethodon. Overall, the courtship behavior of this species is most similar to that of P. jordani.