Relationship between corolla length and floral larceny in the South America hummingbird-pollinated Campsidium valdivianum (Bignoniaceae)

URCELAY CARLOS; MORALES CAROLINA LAURA; CHALCOFF VANINA RUTH

Annales Botanici Fennici

Finnish Zoological and Botanical Publishing Board

Año: 2006 vol. 43 p. 205 - 211

0003-3847

Flowers with pink or red tubular corollas have been traditionally viewed as adapted for pollination by birds. However, tubular fowers frequently suffer illegitimate visits by nectar robbers. Campsidium valdivianum (Bignoniaceae) is an endemic hummingbird pollinated climber with pinkish-red tubular fowers, which suffers high levels of foral larceny by a native bumblebee. We studied two populations of C. valdivianum in an Andean forest in South America and found that they differ signifcantly in their mean corolla length but not in their mean corolla width. The proportion of robbed flowers, as well as the mean number of holes per robbed fower was higher in the population with higher mean corolla length. Although robbing levels also differed between individuals within populations, corolla length was only signifcantly related to robbing frequency in the population with longest corollas. The positive relationship between corolla lBOMBUS DAHLBOMIIength and nectar robbing observed here might affect the fitness in this species and thus the direction and magnitude of selection of the foral trait.