On the pollination of Bejaria resinosa Mutis ex Linné f. (Ericaceae), an ornithophilous Andean páramo shrub

Abstract

At the Colombian Páramo de Los Dominguez, 3.700 m a.s.l., the role of hummingbirds as pollinators of the ornithophilous Bejaria resinosa was examined. Despite the plants appearance, flower visits by hummingbirds are extremely rare. Obviously, the rather short-billed species are not able to reach the nectar. At the shrubby habitats preferred by the hummingbirds, the available nectar is reduced by nectar-robbing flowerpiercers by some 60%. The low visiting frequency of hummingbirds may be compensated by the high degree of self-compatibility, the long anthesis and the sticky viscin threads that last on the birds for a long time. Additionally, the flowers are very attractive to bumble bees, which show much higher visiting frequencies than hummingbirds and seem to be the plants' most effective pollinators at the site. Hummingbirds, however, may still play an important role for long-distance pollination. The flowering peak in the dry season and the highly concentrated nectar may be judged as preconditions for a shift to bumble bee pollination.