Perceived predation risk as a function of predator dietary cues in terrestrial salamanders

• Published in: Animal behaviour Vol. 57; no. 1; pp. 33 - 39
• Main Authors: MURRAY, DENNIS L., JENKINS, CHRISTOPHER L.
• Format: Journal Article
• Language: English
• Published: Kent Elsevier Ltd 01.01.1999; Elsevier; Harcourt Brace Jovanovich Ltd
• Subjects: Amphibia and reptilia; Animal behavior; Animal ethology; Aquatic environment; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Lumbricus; Plethodon cinereus; Predation; Predators; Prey; Psychology. Psychoanalysis. Psychiatry; Reptiles & amphibians; Thamnophis sirtalis; Vertebrata; Laboratory study; Caudata; Defensive behavior; Amphibia; Risk; Feeding; Vertebrata; Plethodon cinereus; Diet; Antipredator behavior; Predator; Predation; Chemical stimulus
• ISSN: 0003-3472; 1095-8282
• DOI: 10.1006/anbe.1998.0986

Prey often avoid predator chemical cues, and in aquatic systems, prey may even appraise predation risk via cues associated with the predator’s diet. However, this relationship has not been shown for terrestrial predator–prey systems, where the proximity of predators and prey, and the intensity of predator chemical cues in the environment, may be less than in aquatic systems. In the laboratory, we tested behavioural responses (avoidance, habituation and activity) of terrestrial red-backed salamanders,Plethodon cinereus, to chemical cues from garter snakes,Thamnophis sirtalis, fed either red-backed salamanders or earthworms (Lumbricusspp.). We placed salamanders in arenas lined with paper towels pretreated with snake chemicals, and monitored salamander movements during 120min. Salamanders avoided substrates preconditioned by earthworm-fed (avoidanceX±SE=91.1±2.5%,N=25) and salamander-fed (95.2±2.5%,N=25) snakes, when tested against untreated substrate (control). Salamanders avoided cues from salamander-fed snakes more strongly (75.2±5.5%,N=25) than earthworm-fed snakes when subjected to both treatments simultaneously, implying that salamanders were sensitive to predator diet. Salamanders tended to avoid snake substrate more strongly during the last 60min of a trial, but activity patterns were similar between salamanders exposed exclusively to control substrate versus those subject to snake cues. In another experiment, salamanders failed to avoid cues from dead conspecifics, suggesting that the stronger avoidance of salamander-fed snakes in the previous experiment was not directly due to chemical cues emitted by predator-killed salamanders. Salamanders also did not discriminate between cues from a salamander-fed snake versus a salamander-fed snake that was recently switched (i.e. <14 days) to an earthworm diet. Our results imply that terrestrial salamanders are sensitive to perceived predation risk via by-products of predator diet, and that snake predators rather than dead salamanders may be largely responsible for the release of such chemicals.