Pollination ecology of Justicia rusbyi (Acanthaceae), a common understory plant in a tropical mountain forest in eastern Bolivia

Abstract

The present study reports the species composition, behavior and ecology of floral visitors to a common understory herb, Justicia rusbyi (Acanthaceae), in a tropical mountain forest. Although the analyses were made during the peak flowering period, floral visitors were rare. In total, 22 species were observed visiting. The most frequent visitors were a small species of stingless bee (Meliponinae) and a skipper (Hesperiidae). Approximately three-quarters of all floral visitors visited only one flower during a stay. Most visitors were observed at noon and in direct sunlight, and there was a positive correlation between the number of J. rusbyi flowers displayed and the number of visitors. The nectar was found to be rich in hexose, which is unusual in bee-pollinated plants.