Deceptive orchids with Meliponini as pollinators

Visitation of orchids by Meliponini (stingless bees) is confirmed only in 13 Melipona, Partamona and Trigona, for Xylobium and Maxillaria, with the addition of Trigona fulviventris visiting Ionopsis. Some bees evinced multiple floral visitation by carrying several stipes and viscidia from pollinaria, thus may cause seed set. None foraged pseudopollen, nor is collection of this substance by bees verified. Meliponine-visited orchids had pollinia in quartets with emplacement on the bee's scutellum, possibly devices for pollinia survival on a social bee passing through its nest. Further, orchids produced no nectar, but bees repeatedly came to flowers. A testable basis for the orchid-meliponine relationship is mimicry of rewarding resources, or bee pheromone mimicry, recently documented for some honey bees. Meliponine pheromone analogs (nerol and 2-heptanol) are here noted for Maxillaria, but lack of foraging with pheromones by Melipona suggests multiple avenues of mimicry by orchids, including alarm pheromone and carrion mimicry.