By Haleigh A. Ray & Jennifer L. Gillett-Kaufman
 |
| (L) An epiphytic Camylocentrum pachyrrhizum in Collier County, Florida. Photograph by Haleigh Ray, and (R) a terrestrial Habenaria sp. In Volusia County, Florida. Photograph by Kirsten Work |
With nearly 30,000 different species orchids are the second largest plant family. Despite this large number, there are still many questions about the pollination biology of orchids. These orchids can grow terrestrially like many other plants, or as epiphytes, where they will grow on another living host, most often the branches or trunk of a tree, without harming the tree. While many orchid pollinators are insects, there have also been birds and a single mammal species identified as successful pollinators. In this paper we review various pollination strategies that orchids use, and analyze a comparison between terrestrial and epiphytic orchids, including whether their growth type influences their pollinator diversity. Over 400 species of orchids and their documented pollinators were included from published literature, including orchids from 50 different countries. Of the orchid species in this review, 55% were pollinated by bees and wasps, 20% by flies, 16% by butterflies and moths, 4% by beetles, and 3.5% by birds. When comparing the epiphytic orchids to the terrestrial orchids, we found that the bees and beetles pollinated more terrestrial taxa than epiphytic, while there was no difference from the other pollinators. Additionally, the terrestrial orchids were pollinated by more pollinator taxa than the epiphytes, suggesting that they have more diverse pollination strategies. With orchids facing threats from poaching, climate change, and habitat loss, learning more about their reproduction is crucial for ensuring their conservation.
