Deceptive pollination of Ionopsis utricularioides (Oncidiinae: Orchidaceae)

Abstract

Oncidiinae is one of the largest and most diverse subtribes within Orchidaceae, and many species of this group are known for relying on deceptive pollination through Batesian floral mimicry. Ionopsis utricularioides is a widespread Oncidiinae orchid that occurs from tropical South America to Florida, USA. The pollinators of this species are still unknown, but a previous study in Puerto Rico showed that the species is rewardless and self-compatible. Here we investigate the pollination biology of I. utricularioides in Brazil. To determine if this species is a Batesian mimic we specifically take into account the flower colour of this species and the co-flowering plants in the community. The breeding system experiments revealed that Brazilian populations of I. utricularioides are completely self-incompatible and produces less fruits than those from Puerto Rico under natural conditions. The flowers of I. utricularioides are also nectarless in Brazil and are pollinated by several bee species. The pollinarium is attached on the dorsal portion of the proboscis, while the pollinators put their head inside the flowers searching for nectar. Given that the flower colour is common to several other co-flowering species of the community, our results suggest that this orchid does not represent a case of Batesian mimicry, since it does not mimic a specific model.