Evol Ecol Res 3: 767-778 (2001)     Full PDF if your library subscribes.

Ultraviolet reflectance in fruits, ambient light composition and fruit removal in a tropical forest

Douglas L. Altshuler

Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-1392, USA

Address all correspondence to Douglas L. Altshuler, Section of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA.
e-mail: colibri@uts.cc.utexas.edu

ABSTRACT

Ultraviolet (UV) reflectance patterns in fruits and UV perception ability in frugivores were linked through a fruit survey and with a field experiment that examined fruit removal under varying light conditions. The reflectance spectra were measured for fruits from 57 tropical plant species on Barro Colorado Island, Panama. Relationships among UV reflectance in fruits, colour vision of the dispersal agents, light regime and fruit ripening were examined using both non-phylogenetic tests and the concentrated changes test to analyse the phylogenetic distributions of these traits. Ultraviolet-reflecting fruits occurred in both open and closed light habitats and were strongly associated with dispersal by birds and rodents, both of which perceive UV radiation. In addition, only mature fruits reflected UV. Natural rates of fruit removal were studied experimentally over 3 months in the understorey shrub Psychotria emetica (Rubiaceae). Ambient light was manipulated by placing a UV-absorbing filter over fruiting plants, with control treatments of plants under clear filters (UV-transmitting) and plants without filters. Fewer fruits were removed when ambient UV was filtered out, establishing that ultraviolet reflectance can be an important attractant for some fruit dispersers. The results indicate a prominent role for UV reflectance in plant–frugivore relations and demonstrate a link between the perceptual abilities of animals and the colour of the fruits they consume.

Keywords: dispersal agent, fruit phenology, fruit removal, light habitat, Psychotria emetica, ultraviolet-reflecting fruits.

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        © 2001 Douglas L. Altshuler. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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