Pseudocopulation of an orchid by male ants: a test of two hypotheses accounting for the rarity of ant pollination.

The orchid Leporella fimbriata is pollinated by pseudocopulation with winged males of the ant Myrmecia urens. This recently studied interaction provides a unique opportunity to examine the two current hypotheses concerning the apparent rarity of ant pollination systems worldwide. The first hypothesis requires a series of specialized growth forms and floral characteristics regarded as adaptations to ant pollination. L. fimbriata does not possess them. The second considers the pollenicidal effects of secretions from the metapleural gland of ants. These glands are absent in M. urens males and it may be that the occurrence of ant pollination requires the absence of metapleural glands in the vector.