Chemosensory Responses of Salamanders to Snake Odors
Some prey species avoid predators using flight or freeze responses, while some may show either response depending on the ecological context. Consequently, predator avoidance may be risk-sensitive, and the level of activity may be an important risk-specific component of the avoidance response. Red-backed salamanders, Plethodon cinereus, were exposed at times of low risk (night) and high risk (day) to the substrate odors of predatory garter snakes (Thamnophis sirtalis) maintained on low risk (goldfish) and high risk (redbacked salamander) diets. Salamanders maximally avoided snake odors over blank substrates in all except the lowest risk treatment, which was not avoided, and thus they appeared to show a threshold (all or none) response to snake odors. However, the concurrent activity level of the salamander (degree of movement during avoidance) showed small scale increases with each risk increment from the lowest risk treatment (goldfish diet at night) to the highest risk treatment (salamander diet during day). There was no evidence of a freeze response during predator avoidance. Partial ”dissociation” of avoidance and activity at night, i.e. no change in avoidance with a change in activity level, or vice versa, is discussed in the context of the biology of P. cinereus. Future studies of predator avoidance behavior should closely examine prey activity for clues to the diversity and intensity of risks that ultimately shape predator avoidance.
KeywordsPredation Risk Predator Avoidance Garter Snake Freeze Response Salamander Larva
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- Burghardt, G. M. 1990. Chemically mediated predation in vertebrates: diversity, ontogeny and information. In: Chemical Signals in Vertebrates 5 (Ed. by D.W. Macdonald, D. Muller-Schwarze & S. E. Natynczuk), pp 475–499. New York: Oxford Univ. Press.Google Scholar
- Brandon, R. A. & Huheey, J. E. 1975. Diurnal activity, avian predation, and the question of warning coloration and cryptic coloration in salamanaders. Herpetol, 31, 252–255.Google Scholar
- Brodie E. D., Jr., Johnson J. A., & Dodd C. K., Jr. 1974. Immobility as a defensive behavior in salamanders. Herpetol, 30, 79–85.Google Scholar
- Gibbons, J. W. & Semlitsch, R. D. 1987. Activity patterns. In: Snakes: Ecology and Evolutionary Biology (Ed.by R. A. Seigel, J. T. Collins & S. S. Novak), pp 396–421. New York: Macmillan.Google Scholar
- Heinen, J. T. 1995. Predator cues and prey responses: A test using eastern garter snakes (Thamnophis s. sirtalis) and American toads (Bufo a. americanus).Copeia, 1995, 738–741.Google Scholar
- Jaeger, R. 1978. Plant climbing by salamanders: periodic availability of plant-dwelling prey. Copeia, 1978, 686–691.Google Scholar
- Madison, D.M., McDarby, J. H. & Maerz, J. C. 1999. Economy of avoidance of snake odors by salamanders: Diet and diel contingencies. Ethiology, in press.Google Scholar
- McDarby, J. H. 1997. Chemosensory avoidance of predators by the red-backed salamander, Plethodon cinereus. M. A. Thesis, State University of New York, Binghamton, NY.Google Scholar
- McDarby J. H., Madison, D.M. & Maerz, J. C. In press. Chemosensory avoidance of predators by the red-backed salamander, Plethodon cinereus. In: Advances in Chemical Signals in Vertebrates (Ed. by R. Johnston), pp. 489–496. New York: Plenum Publ. Corp.Google Scholar
- Siegel S. & Castellan N. J., Jr. 1988. Nonparametric Statistics for the Behavioral Sciences. New York: McGraw-Hill.Google Scholar
- Smith, R. J. 1997. Avoiding and deterring predators. In: Behavioural Ecology of Teleost Fishes (Ed. by J. J. Godin), pp. 163–190. New York: Oxford Univ. Press.Google Scholar
- Turner, A. M. 1994. The effects of predator mediated habitat use on consumer-resource interactions. Ph. D. thesis, Michigan State University, East Lansing.Google Scholar