Preliminary observations on the flower visitors of Nasa colanii (Loasaceae), a poorly known species endemic to northern Peru

Abstract

Nasa is the most diverse genus among the family Loasaceae and it is mainly distributed in Peru. Most species of this genus are microendemics, with distributions restricted to very specific locations; such is the case of Nasa colanii Dostert & Weigend. This species — previously only known from the type collected in 1978 from the Amazonas region of Peru — lacks information about its biology and ecology. To improve our understanding of the reproductive biology and pollination ecology of N. colanii, we observed flower development and insect floral visits in a cloud forest in the Amazonas region. The flowers of N. colanii are nectariferous and protandrous. The typical stamen movement to the flower center of the subfamily Loasoideae appears to be autonomous. Only well-developed (elongated) pistils showed positive stigmatic receptivity to 3% hydrogen peroxide. Syrphid flies (Baccha sp.) and small beetles (Baridinae spp. and Alticini sp.) were the only observed flower visitors. The syrphid flies visited the flower and foraged for pollen, whereas the small beetles were found already in the flowers and seemingly used it as a shelter. Results suggest that N. colanii might be adapted to fly pollination.