Primates are apparently unique amongst the mammals in possessing trichromatic colour vision. However, not all primates are trichromatic. Amongst the haplorhine (higher) primates, the catarrhines possess uniformly trichromatic colour vision, whereas most of the platyrrhine species exhibit polymorphic colour vision, with a variety of dichromatic and trichromatic phenotypes within the population. It has been suggested that trichromacy in primates and the reflectance functions of certain tropical fruits are aspects of a coevolved seed-dispersal system: primate colour vision has been shaped by the need to find coloured fruits amongst foliage, and the fruits themselves have evolved to be salient to primates and so secure dissemination of their seeds. We review the evidence for and against this hypothesis and we report an empirical test: we show that the spectral positioning of the cone pigments found in trichromatic South American primates is well matched to the task of detecting fruits against a background of leaves. We further report that particular trichromatic platyrrhine phenotypes may be better suited than others to foraging for particular fruits under particular conditions of illumination; and we discuss possible explanations for the maintenance of polymorphic colour vision amongst the platyrrhines.

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The impact of deforestation on the composition and dynamics of bat communities received close attention during a 15-year survey of the bats of French Guiana. Overall, deforestation lowers species richness: 48 of the 75 bat species from primary forest, mainly mature-forest phyllostomids, were not found in large areas that had been deforested for a long time. The 27 "rare" species, each represented by fewer than 6 of 8031 captures, had been apparently virtually eliminated from deforested areas. These altered habitats had been repopulated by a few opportunistic frugivorous phyllostomid species and by species belonging to the widespread insectivorous families Vespertilionidae and Molossidae. Habitats altered by humans harbor over four times as many individual bats as primary rain forest. This rise in both frugivorous and insectivorous bat populations in areas of degraded vegetation appears linked to the abundance of bat-dispersed pioneer' fruiting plant species available to phyllostomids and the multiplication of roosting sites for vespertilionids and molossids in human habitats. The species richness of local bat communities is positively influenced by the presence of forest corridors or the immediate proximity of a forest block.