Glenn A. Marvin

Bio: Glenn A. Marvin is an academic researcher from University of Oklahoma. The author has contributed to research in topics: Salamander & Plethodon kentucki. The author has an hindex of 7, co-authored 8 publications receiving 226 citations. Previous affiliations of Glenn A. Marvin include University of Montevallo.

Avoidance Response By Adult Newts (Cynops Pyrrhogaster and Notophthalmus Viridescens) To Chemical Alarm Cues

Abstract: Many fishes and aquatic invertebrates use chemical alarm cues to avoid predation, however relatively little is known about the occurrence of chemical alarm cues in amphibians We tested the response of adult fire-bellied newts (Cynops pyrrhogaster) and red-spotted newts (Notophthalmus viridescens) to chemical cues from damaged tissues of newts and other salamanders Both species avoided chemical cues from a conspecific skin extract Notophthalmus viridescens also avoided chemical cues from C pyrrhogaster skin extract, but the converse was not true Neither species avoided chemical cues from a conspecific viscera extract, plethodontid salamander (Desmognathus and Plethodon) skin extracts, or a conspecific skin extract which had been heated These results indicate that the avoidance behaviour is an alarm response to chemical cues released from damaged newt skin and is not a general response to chemical cues from damaged salamander tissue This study provides the best evidence to date for an avoidance response by caudate amphibians to chemical alarm cues

Alarm response by a plethodontid salamander (Desmognathus ochrophaeus): Conspecific and heterospecific "Schreckstoff".

Abstract: The detection of chemical alarm cues plays an important role for predator avoidance in many taxonomic groups, but little is known about the presence of such chemical cues in adult or caudate amphibians. We investigated the response (i.e., aversion or nonaversion) to chemical cues from damaged salamander skin and mealworms (Tenebrio molitor) in the plethodontid salamander,Desmognathus ochrophaeus. Avoidance responses were demonstrated to skin extracts of both conspecific and heterospecific salamanders. However, salamanders (D. ochrophaeus) did not avoid heated conspecific skin, fresh conspecific viscera, fresh mealworm, or freshPlethodon richmondi skin extracts. These results indicate that chemical alarm cues are: (1) present in the skin ofDesmognathus salamanders, (2) not present in mealworm or the viscera ofDesmognathus salamanders, and (3) denatured or deactivated by heating. These results also suggest that an avoidance response to chemical cues from damaged conspecifics has adaptive value in predator avoidance in terrestrial as well as aquatic vertebrates.

Territorial behavior of the plethodontid salamander Plethodon kentucki: influence of habitat structure and population density.

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.

Thermoregulation in the box turtles Terrapene carolina and Terrapene ornata

Abstract: Terrapene ornata and Terrapene carolina are box turtles that live in different habitats, the former in grasslands and desert edges and the latter in forested areas. Considering these species' habitat selection, we predicted that T. ornata would select a higher body temperature (Tb) and would be a more precise thermoregulator than T. carolina. We recorded time series of cloacal Tb's in thigmothermal linear gradients from acclimatized (12 h light : 12 h dark; 10 or 20°C) box turtles. We used three analytical methods to evaluate and characterize turtles' activity: a ratio-dependent index that measured activity as an indirect function of changes in Tb, a comparison of hourly mean variances of Tb (ratio-independent), and autocorrelation. We tested the thermoregulatory differences between active T. carolina and T. ornata with a factorial ANOVA and characterized the turtles' thermoregulatory cycles with correlograms. Overall, T. ornata had significantly higher mean Tb's than T. carolina. The two species had simi...

Courtship Behavior of the Cumberland Plateau Woodland Salamander, Plethodon kentucki (Amphibia: Plethodontidae), with a Review of Courtship in the Genus Plethodon

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.

Chemical alarm signalling in aquatic predator-prey systems: A review and prospectus

Abstract: The importance of chemical cues in predator-prey interactions has recently received increasing attention from ecologists. The sources of chemicals to which prey species respond often originate as cues released by the predator (reviewed by Kats and Dill, this issue). Alternatively, cues may be released by other prey animals when they detect or are attacked by a predator. Such cues, known as chemical alarm signals, are particularly common in aquatic systems. These signals provide the basis of our current review. Short-term behavioural responses of prey animals to alarm signals have received the most attention. Behavioural responses of prey resemble those exhibited to known predators, and are therefore likely to make receivers less vulnerable to predation. More recently, studies have shown that benefits to alarm signal receivers extend beyond the immediate behavioural response of nearby conspecifics over a few minutes. For example, alarm signals are important in mediating the learning of unknown pred...

Dispersal and the metapopulation paradigm in amphibian ecology and conservation : are all amphibian populations metapopulations?

Abstract: Amphibians are frequently characterized as having limited dispersal abilities, strong site fidelity and spatially disjunct breeding habitat. As such, pond-breeding species are often alleged to form metapopulations. Amphibian species worldwide appear to be suffering population level declines caused, at least in part, by the degradation and fragmentation of habitat and the intervening areas between habitat patches. If the simplification of amphibians occupying metapopulations is accurate, then a regionally based conservation strategy, informed by metapopulation theory, is a powerful tool to estimate the isolation and extinction risk of ponds or populations. However, to date no attempt to assess the class-wide generalization of amphibian populations as metapopulations has been made. We reviewed the literature on amphibians as metapopulations (53 journal articles or theses) and amphibian dispersal (166 journal articles or theses for 53 anuran species and 37 salamander species) to evaluate whether the conditions for metapopulation structure had been tested, whether pond isolation was based only on the assumption of limited dispersal, and whether amphibian dispersal was uniformly limited. We found that in the majority of cases (74%) the assumptions of the metapopulation paradigm were not tested. Breeding patch isolation via limited dispersal and/or strong site fidelity was the most frequently implicated or tested metapopulation condition, however we found strong evidence that amphibian dispersal is not as uniformly limited as is often thought. The frequency distribution of maximum movements for anurans and salamanders was well described by an inverse power law. This relationship predicts that distances beneath 11–13 and 8–9 km, respectively, are in a range that they may receive one emigrating individual. Populations isolated by distances approaching this range are perhaps more likely to exhibit metapopulation structure than less isolated populations. Those studies that covered larger areas also tended to report longer maximum movement distances – a pattern with implications for the design of mark-recapture studies. Caution should be exercised in the application of the metapopulation approach to amphibian population conservation. Some amphibian populations are structured as metapopulations – but not all.

The evolution of pheromone diversity.

Abstract: Pheromones are chemical signals whose composition varies enormously between species. Despite pheromones being a nearly ubiquitous form of communication, particularly among insects, our understanding of how this diversity has arisen, and the processes driving the evolution of pheromones, is less developed than that for visual and auditory signals. Studies of phylogeny, genetics and ecological processes are providing new insights into the patterns, mechanisms and drivers of pheromone evolution, and there is a wealth of information now available for analysis. Future research could profitably use these data by employing phylogenetic comparative techniques to identify ecological correlates of pheromone composition. Genetic analyses are also needed to gain a clearer picture of how changes in receivers are associated with changes in the signal.

Chemical Detection of Natural Enemies by Arthropods: An Ecological Perspective

Abstract: Food webs are overlaid with infochemical webs that mediate direct and indirect interactions. The infochemicals may result in shifts in trait values, which affect the strength of species interactions. As a consequence, population dynamics and evolutionary changes can be affected. Chemical information can mediate the interactions between animals and their resources, competitors and enemies. Of all chemical information gathered by animals, cues about predation risk are of special significance because predation risk usually has important and immediate consequences on fitness. In this paper we selectively review the role of chemical information in enemy avoidance by arthropods. Arthropods not only constitute important components of food webs, being the largest group in numbers and species diversity; they also make excellent models for ecological studies. We discuss the evidence, the key mechanisms, and the trade-offs involved in chemical detection of enemies by potential arthropod prey. Further, we address the variation in prey responses and the evidence for learning in avoiding enemies by arthropods. Finally, we identify and prioritize major questions to be tackled by future studies.

The Biology of Plethodontid Salamanders

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