Foliage color contrasts and adaptive fruit color variation in a bird‐dispersed plant community

Abstract

J. L. 2002. Foliage color contrasts and adaptive fruit color variation in a bird-dispersed plant community. -Oikos 96: 463-469.The color of vertebrate-dispersed fruits has been a source of inquiry for over 150 years, yet the ecological and evolutionary processes responsible for fruit color diversity remain elusive. We tested the hypothesis that fruit color varies temporally, to maximize conspicuousness against seasonal changes in foliage coloration, in a bird-dispersed plant community in western North America. Field observations showed that while red fruits predominate during summer periods of green foliage coloration, black fruits are produced during flushes of red-orange foliage coloration in autumn. Although two species did not conform to this pattern, one produced its own contrasting background color, via colored bracts. We conducted experimental manipulations of both fruit color and the color of artificial backgrounds to test whether both factors had a synergistic effect on fruit removal rates. Interactions between fruit and background color explained most of the variation in experimental fruit removal rates. Although red fruits were removed rapidly on green backgrounds, preference for black fruits on red-orange backgrounds was less pronounced. Consequently, the temporal pattern in fruit color appears to result from elevated fruit conspicuousness against seasonal changes in foliage coloration. Support for this hypothesis suggests a temporal connection between fruit color diversity, foliage color contrasts and avian color preferences.

Rapid assessment of fruit-color selection by birds using artificial fruits at local scale in Central Amazonia

“…Although inconclusive about selective forces that sharp the dynamics of fruit color polymorphisms and choice by frugivorous birds, our findings corroborated recent studies wherein birds showed preferences by high-over low-contrast fruit signals (e.g. Burns & Dalen, 2002;Schmidt et al, 2004).…”

“…As birds discriminate between fruit colors, our results suggests that the perception of color by birds was not influenced by use of artificial fruits (see also Alves-Costa & Lopes, 2001). Burns & Dalen (2002) and Schmidt et al (2004) found strong support for the prediction that background foliage coloration influences fruit color preferences by avian frugivores. These authors demonstrated that red fruits had higher removal rates because displayed against contrasting background foliage.…”

How plant?animal interactions signal new insights in communication

“…† Flowers and fruits are often displayed against conspicuously coloured, non-green secondary structures, such as coloured infructescences and bracts [19,62]. Do these structures enhance detectability according to the eye of the receiver?…”

Geographic patterns in fruit colour diversity: do leaves constrain the colour of fleshy fruits?

“…Rather, fruit conspicuousness results from spectral contrasts between fruits and their backgrounds (Burns and Dalen 2002;Schmidt et al 2004). Selection by frugivores is therefore likely to favour colours that are perceived as strongly contrasting with their backgrounds, because strong fruitbackground contrasts are more conspicuous and increase the chances that fruits are detected (Schaefer et al 2006).…”