Relationship between corolla length and floral larceny in the South American 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

Abstract Flowers with pink or red tubular corollas have been traditionally viewed as adapted for pollination by birds.  However, tubular flowers frequently suffer illegitimate visits by nectar robbers.  Campsidium valdivianum (Bignoniaceae) is an endemic hummingbird-pollinated climber with pinkish-red tubular flowers, which suffers high levels of floral larceny by a native bumblebee.  We studied two populations of C. valdivianum in an andean forest in South Americ and found that they differ significantly 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 flower was higher in the population with higher mean corolla length. Although robbing levels also differed between individuals within populations, corolla length was only significantly related to robbing frequency in the population with longest corollas. The positive relationship between corolla length and nectar robbing observed here, might affect the fitness in this species and thus the direction and magnitude of selection of the floral trait. Keywords: Bombus dahlbomii, bumblebee, floral traits, nectar robbing, robbing frequency