Pollinators of Helleborus niger in Slovenian naturally occurring populations

Abstract

The study is based on documentation and analysis of the major visitors and pollinators of the Christmas rose (Helleborus niger L.) flowers in Slovenian naturally occurring populations. The emphasis was put on 5 groups of insects: bees, bumblebees, large flies, small dipterous flies and pollinators of minor importance. Systematic observations took place in March 2003, at two different locations: on the valley of Bohinjska Bela and on the Peca Mountain. The first location was not far from a rural area, while the second one was in an isolated area, completely in the wild. The analysis of insect activity showed that there were obvious differences in frequency of visits among the insect groups investigated, locations and time of day. In the population of Bohinjska Bela, bees were the most important pollinators, with the highest activity occurred between 10 a.m. and 11 a.m. In the isolated population in Peca the most frequent visitors were small dipterous flies. The study suggests that the Christmas rose is probably an entomophylous (the most important pollinators are insects, such as bees and flies) and predominantly cross-pollinating species. The entomophylous nature appears to be closely associated with the specific botanic characteristics of flowers. Another pollinating agent is probably wind.

Keywords

• Christmas rose
• Helleborus niger
• wild populations
• pollination