Hummingbirds are often thought as an important element of the reproductive ecology of many Heliconia species. We studied the reproductive ecology of a yellow bracted variety of Heliconia caribbaea in the Luquillo Mountains to address this assumption. In particular we investigated the extent of visitation by hummingbirds, the potential for self-pollination and reproductive differences due to differences in mating patterns as well as the role of other ecological factors (i.e. herbivory) in the outcome of plant reproduction. Our results suggest that hummingbirds may not be an important determinant of the outcome of sexual reproduction in this species as assumed based on a hypothesis of a hummingbird-type flower syndrome.

This presentation is suitable for Scientific- Beginning to Intermediate heliconia growers.

The understory herb Heliconia bihai has long been known to be a highly polymorphic species in which close to 24 varieties are believed to exist both in the wild and in cultivation. We performed a quantitative examination of the distribution of morphological and genetic variation within and between populations of H. bihai in the Caribbean islands of St. Vincent and St. Lucia. Morphological characterization was limited to flower and inflorescence characteristics including bract color. AFLPs were used to investigate levels of genetic diversity within and between populations using four primer pairs. Genetic similarity among individuals was equivalent to that expected for conspecific individuals. Levels of AFLP polymorphism and population subdivision were high and comparable to those of outcrossing species in one island but they were low and comparable with selfing or clonal species in the other suggesting that genetic variation between islands may be under different evolutionary regimes. There was a significant geographical structure in morphological variation but this was considerably less pronounced than that found at the genetic level except for bract color patterns, which were different for different islands. We found no correlation between genetic similarity and geographic distance, or between genetic similarity and morphological similarity. Overall, results fail to support a hypothesis of genetic isolation as the main driving force of polymorphism in Heliconia bihai through out its geographic range. Rather, observed patterns of genetic and morphological variation are consistent with a number of evolutionary phenomena that may be operating independently at different levels on this species.

Dra. Elvia Melendez-Akerman joins us from University of Puerto Rico in Puerto Rico.