Orchid Biology: Darwin`s Contrivances 150 Years Later
Arevalo Burbano, Rafael , Cameron, Kenneth .
Labellar micro-morphology and diversification in Mormolyca (Orchidaceae:Maxillariinae): deception or reward?
Orchids are notorious for attracting pollinators by deceit (e.g., a false promise of food or sexual partner), but many orchids do, in fact, offer rewards to insect pollinators in the form of nectar, fragrance, oils, brood sites, resins, and waxes. Depending on the particular pollination syndrome, a unique combination of features such as flower color, shape, size, fragrance, and/or pilosity serve to attract specific pollinators. In the Neotropical subtribe Maxillariinae, the labella of most species are generally covered with abundant epidermal papillae that function either as food source, as odor emitters (osmophores), as visual cues, or have an as-yet unknown function. Within the subtribe, the genus Mormolyca, with only 25 species, exhibits both reward-offering and rewardless species. As flower variation among species is almost certainly related to their pollination strategy, reproductive morphological features like the labellar papillae, could be useful to good effect in predicting pollination syndromes. Information on the micro-morphological nature of labellar structures was collected for more than 2/3 of the species found in Mormolyca, and in combination with the phylogenetic reconstruction, we assess the evolution of labellar micro-morphology and their relation with pollination syndromes. Labellar papillae that tested positive for the presence of proteins, starch and/or lipids were found in species from the most derived clade. The distribution of these potential food substances for foraging, depict a single origin for food rewards. We speculate that food deception is present in species with pollen-like papillae that lack any potential food substance. With sexual deception being a more ancestral trait, it is likely that food deception evolved from sexual deception, contrary to what has been observed in temperate orchids
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1 - University Of Wisconsin, Botany, 244 Birge Hall, 430 Lincoln Dr., Madison, WI, 53706, USA
2 - University Of Wisconsin, Department Of Botany, 154 Birge Hall, 450 Lincoln Drive, Madison, WI, 53706, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Franklin B/Hyatt
Date: Wednesday, July 11th, 2012
Time: 2:15 PM