The Influence of Substrate Color on the Alarm Response of Tidepool Sculpins (Oligocottus maculosus; Pisces, Cottidae)

Authors

  • Robert Houtman,

    Corresponding author
    1. Behavioural Ecology Research Group, Department of Biological Sciences, Simon Eraser University, Burnaby
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      Houtman, R. & Dill, L. M. 1994: The influence of substrate color on the alarm response of tidepool sculpins (Oligocottus maculosus; Pisces, Cottidae). Ethology 96, 147–154.

  • Lawrence M. Dill

    1. Behavioural Ecology Research Group, Department of Biological Sciences, Simon Eraser University, Burnaby
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      Houtman, R. & Dill, L. M. 1994: The influence of substrate color on the alarm response of tidepool sculpins (Oligocottus maculosus; Pisces, Cottidae). Ethology 96, 147–154.


Behavioural Ecology Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, B.C., Canada, V5A 1S6.

Abstract

For animals that use crypsis to avoid predators, immobility reduces the risk of detection. The magnitude of this immobility benefit depends upon the probability that a predator is present, since a predator must be present for crypsis to be valuable. Thus, cryptic animals typically reduce their movement rates upon detection of a nearby predator or signs of its activity. Such a response occurs in tidepool sculpins (Oligocottus maculosus) when presented with water-borne compounds released from the skin of injured conspecifics (Hugie et al. 1991). The benefit of immobility should also depend upon the animal's background, or substrate, since animals on a matching substrate achieve a higher level of crypticity than those on a nonmatching substrate, and have more to gain by remaining still. Therefore, we predicted that the response of tidepool sculpins to conspecific skin extract would involve a greater reduction in movement rates for fish on sand (matching) than for those on white (nonmatching) substrate. The results of a laboratory experiment supported this prediction, with fish on sand showing a large decrease in movement rates in response to skin extract, while the movement rates of those on white substrate remained unchanged.

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