Habitat selection in larval anurans: early experience and substrate pattern selection in Rana pipiens.

The tadpoles of Rana pipiens, unlike those of other frogs that have been reported on, do not develop clear-cut perceptual preferences for familiar background patterns composed of either squares or stripes. When larvae reared on white and/or patterned backgrounds are tested for preference between these backgrounds, they all exhibited a preference for white backgrounds. When the larvae were tested for preference among uniform backgrounds of varying brightness, those reared on the two brighter backgrounds showed no preference, and those reared on the two darker backgrounds preferred the brightest of the available backgrounds. The larvae of R. pipiens behave as if they possess an experientially modifiable defense reaction such that, when frightened, they move preferentially onto brighter backgrounds and avoid boldly patterned backgrounds. A pattern may be less aversive if it is familiar than if it is unfamiliar. Larvae from South Dakota tended to habituate more effectively to striped backgrounds, and those from Wisconsin to backgrounds composed of squares.