COEVOLUTION IN AN AMAZONIAN HUMMINGBIRD-PLANT COMMUNITY

Relationships between hummingbirds and their food plants are often con sidered to have arisen through coevolution, However, while it is certa inly the case that hummingbirds and plants are coevolved, it is not al ways clear to what extent coevolution has shaped community structure a nd the morphology of the birds and plants. Here I examine the hummingb ird-plant community of a lowland Amazonian rainforest in southeastern Colombia and test hypotheses concerning coevolution and community stru cture. To determine the strength of interrelationships and the degree to which character displacement has occurred, the distributions of thr ee floral traits (flowering phenology, nectar production and corolla l ength) and two hummingbird traits (culmen length and foraging ecology) have been statistically tested against random null models. Although t he hummingbird-plant community at Matamata is diverse and is highly li kely to have a long shared evolutionary history, there is little evide nce for pairwise coevolution. Instead, the community appears to have e volved through diffuse coevolution, resulting in guilds of hummingbird s and plants.