Notes on pollination ecology and floral scent chemistry of the rare neotropical orchid Catasetum galeritum Rchb.f.

The neotropical orchid genus Catasetum embraces about 180 species that produce perfume as reward for pollinators (i.e. male euglossine bees). Among the ca. 1000 perfume‐rewarding plants, Catasetum species are the best studied with respect to their natural history. Nevertheless, the pollination ecology of most species (> 80%) remains unknown. Here, we investigated the pollination ecology and floral scent chemistry of C. galeritum, a rare species endemic to the poorly investigated Brazilian Amazon. Flowers of C. galeritum were visited only by male bees of Eufriesea superba. Its perfume bouquet was composed of six volatiles, with 1,4‐dimethoxybenzene accounting for about 85% of the total scent discharge. Curiously, this compound is a potent attractant of more than 40 euglossine species. The absence of euglossine species other than Ef. superba on flowers of C. galeritum might be, therefore, be mediated by a modifier effect of another compound(s) in its floral scent bouquet.