Behavioral Ecology of the Eastern Red-backed Salamander: 50 Years of Research

The small, terrestrial eastern red-backed salamander is abundant on many forest floors of northeastern North America. Dr. Robert Jaeger and many of his graduate students spent over 50 years studying this species in New York and Virginia, using ecological techniques in forests and behavioral experiments in laboratory chambers in an attempt to understand how this species interacts with other species in the forest and the components of its intra- and intersexual social behaviors. The competitive and social behaviors of this species are unusually complex for an amphibian. This species is highly aggressive towards other similar-size species where they cohabit in forests, often leading to very little geographic overlap between the species. The authors examine the fascinating behavioral traits of this species including social monogamy, mutual mate guarding, sexual coercion, inter-species communication, and conflict resolution.

Table of Contents:
List of Figures Acknowledgments About the Authors Chapter 1: Prelude 1.1 Bob Jaeger meets the eastern red-backed salamander, Plethodon cinereus 1.2 An introduction to red-backed salamanders 1.3 The plot of our research program 1.4 Comments concerning methodology and statistical paradigms Chapter 2: Interspecific competition between P. cinereus and P. shenandoah 2.1 Ecological studies 2.2 Behavioral experiments 2.3 Selected recent research by others: Interspecific competition Chapter 3: Intraspecific territoriality by P. cinereus 3.1 Definition and theory 3.2 Distribution and prey availability 3.3 Site tenacity by P. cinereus 3.4 Determining sex and defining behavioral patterns 3.5 The use of odors and dear enemy recognition 3.6 The expulsion of intruders 3.7 Testing territoriality in the forest 3.8 Variables that affect territorial contests 3.8.1 Length of residency 3.8.2 Body size 3.8.3 Body size without residency 3.8.4 Sex and reproductive condition 3.8.5 Intruder number 3.8.6 Tail condition 3.8.7 Food quantity 3.8.8 Food quality 3.8.9 Signal honesty 3.9 Life history traits and territorial contests 3.9.1 Variation in reproductive success among females 3.9.2 Payoffs to and RHP of territorial owners 3.9.3 Resource acquisition and energy allocation 3.10 Seasonal and geographic variation in territorial agonistic behavior 3.10.1 Seasonal variation 3.10.2 Geographical variation 3.11 Selected recent research by others: Intraspecific territoriality Chapter 4: Foraging tactics by P. cinereus within territories 4.1 Foraging on live versus dead prey 4.2 Diet breadth 4.3 Optimal prey choice 4.4 Territorial and foraging behavioral conflicts 4.5 Assessing prey densities 4.6 Judging prey profitabilities 4.7 Conflicts between foraging behavior and territorial defense 4.8 Diet diversity and clutch size 4.9 Selected recent research by others: Foraging tactics Chapter 5: Pheromonal glands and pheromonal communication by P. cinereus 5.1 Early studies suggest pheromones do occur 5.2 Do males of P. cinereus produce territorial pheromones? 5.3 Do females of P. cinereus produce territorial pheromones? 5.4 Where are those pheromones produced in males and females? 5.5 Focusing on the postcloacal gland 5.6 What information does the postcloacal gland communicate? 5.7 What signals do pheromones communicate? 5.8 Scent matching and tail autotomy 5.9 Do territorial pheromones aid in homing behavior by P. cinereus? 5.10 Are pheromones volatile? 5.11 Selected recent research by others: Pheromonal communication Chapter 6: Interspecific territoriality and other interspecific behavioral interactions 6.1 Interspecific territoriality between P. cinereus and P. shenandoah 6.2 Rules of engagement with juveniles of P. glutinosus 6.3 Plethodon cinereus in an assemblage of salamanders 6.4 Ecological tests of behavioral predictions: Enclosed plots on the forest floor 6.5 More ecological tests of behavioral predictions: Unenclosed plots on the forest floor 6.6 Character displacement: P. cinereus versus P. hoffmani 6.7 Competition between P. cinereus and P. hubrichti 6.7.1 Habitat niche partitioning? 6.7.2 Microhabitat niche partitioning? 6.7.3 Intra- and interspecific competition? 6.7.4 Intra- and interspecific territoriality? 6.7.5 Summary 6.8 Diversity of behaviors by P. cinereus toward other species 6.9 Selected recent research by others: Interspecific territoriality Chapter 7: Intraspecific social behavior within P. cinereus 7.1 Interactions of adults and juveniles in the forest and in the laboratory 7.2 Distributions of adult males and females 7.3 Microdistributions of adults and juveniles 7.4 Female-female interactions 7.5 Male-female behavioral interactions in the forest 7.6 The ESS dating game 7.7 Males, females, and feces 7.8 Females prefer larger males 7.9 Males and females prefer familiar opposite-sex individuals 7.10 Social monogamy 7.11 Mutual mate guarding 7.12 Sexual coercion 7.13 Imperfect information during sexual discrimination? 7.14 Relationship value and conflict resolution 7.15 Natural versus forced partnerships 7.16 Females are often genetically polyandrous 7.17 Switching from social monogamy to social polygamy 7.18 Brooding behavior and neonates: Kin recognition? 7.19 What 3,487 uniquely marked salamanders reveal about social relationships 7.19.1 Basic population ecology 7.19.2 Size distribution and growth rates 7.19.3 Sexual maturity and female fecundity 7.19.4 Population size 7.19.5 Sex ratio 7.19.6 Intersexual associational behavior 7.19.7 Consequences of tail autotomy 7.20 A preliminary model of social organization within P. cinereus 7.21 Selected recent research by others: Social behavior Chapter 8: Predator-prey interactions between P. cinereus and a snake 8.1 Can P. cinereus detect the snake visually or chemically? 8.2 Can the snake detect chemical cues from P. cinereus? 8.3 Naïve snakes recognize odors of P. cinereus 8.4 Tail autotomy deceives the snake 8.5 The snake follows the trail of P. cinereus 8.6 The predator-prey evolutionary arms race 8.7 Selected recent research by others: Predator-prey arms races Chapter 9: Cognitive ecology of P. cinereus 9.1 Numerical discrimination by P. cinereus 9.2 Both learning and heritability affect foraging ability 9.3 Displacement of territorial aggression 9.4. The impact of familiarity on salamander behavior 9.5 Individual recognition memory 9.5.1 The formation of individual recognition memory 9.5.2 Sensory modalities used during recognition 9.5.3 Do distractors inhibit individual recognition memory? 9.5.4 Overview 9.6 Selected recent research by others: Cognitive ecology Chapter 10: Coda: Synthesis and social behaviors by P. cinereus 10.1 Behavioral variation within a population 10.1.1 Age 10.1.2 Tail autotomy 10.1.3 Polymorphism 10.1.4 Health 10.1.5 Bold and shy 10.1.6 Experimental flaws 10.2 Behavioral options during contests 10.3 How salamanders choose among options 10.4 Definitions of social, mating, and genetic monogamy 10.5 Mea maxima culpa References Index

About the Author :
Robert G. Jager is a retired former Professor of Biology at the Unviersity of Lousiana at Lafayette. He has spent the last forty years working on territoriality and interspecific competition in the red-backed salamanders, Plethodon cinereus. He is currently retired but continues to publish actively. Current research examines social behavior and, in particular, social monogamy/polygamy in red-backed salamanders. Birgit Gollmann is a Researcher at the Institut fur Zoologie at the Universitat Wien in Vienna, Austria. Carl D. Anthony is a Professor in the Biology Department at John Carroll University. Caitlin Gabor is a Professor of Biology at Texas State University. Nancy Kohn is an adjunct faculty member in the department of Biology at the College of New Jersey.

Review :
"The research program of Jaeger et al. has had a profound effect not only on our understanding of red-backed salamanders, but has also made clear how remarkably complex animal behavior can be in species once considered lowly and simple. [...] Finally, this volume ends with a call to future scientists: [the studies] reviewed in this book have produced a jigsaw puzzle of P. cinereus, with only a few of the pieces fitting together. We hope that younger colleagues now studying P. cinereus will complete the jigsaw puzzle, or at least add new pieces to it (p. 207). I was certainly inspired to sit down at the puzzle table." -- Andrew Kraemer, The Quarterly Review of Biology