August 31, 2008 | David F. Coppedge

Plant Perfume Manipulates Pollinator Behavior

You’re a plant, stuck in the ground.  Around you are organisms with wings flitting freely about.  You need to get them to land on your flowers, but not linger too long.  How do you do it?  Attract them with sweet smells, but send them away with a bitter aftertaste.  That’s how the tobacco plant manipulates its pollinators (hawkmoths and hummingbirds), according to Science.1  The aftertaste of nicotine is intended to discourage the pollinator from lingering, so that it will be more likely to spread pollen among different plants.
    The scientists found that birds and moths tended to linger too long around the sweet nectar when the nicotine was absent.  Making them drink and move on spreads the plant’s genes around, which helps the plant prevent inbreeding, and forces the pollinators to visit more flowers for their nutrition needs and so get more exercise.
    Robert R. Raguso (Cornell), commenting on a paper in the same issue,2 said, “This study adds to a growing list of ruses by which plants manipulate pollinator movement to optimize gene flow.”  He also noted that the seeds of the tobacco plant, a Mojave desert resident named Nicotiana attenuata, read smoke signals.  “It is a fire-adapted desert annual that can spend decades as a dormant seed, awaiting a smoke signal that will trigger germination.
    Raguso noted that this subtle interaction between plant and pollinator would not have been noticed without attention to the plant perfumes.  “Through the ‘invisible hand’ of floral volatiles, the self-interests of tobacco plants and their pollinators are mediated with an apparent net outcome of mutual benefit.
    Neither the paper or the review mentioned how evolution might have brought about this mutual interaction.  A review of the paper on Science Daily, however, attributed the success of the plants to “the dictates of their Darwinian fitness.”

1.  Kessler, Gase and Baldwin, “Field Experiments with Transformed Plants Reveal the Sense of Floral Scents,” Science, 29 August 2008: Vol. 321. no. 5893, pp. 1200-1202, DOI: 10.1126/science.1160072.
2.  Robert R. Raguso, “The ‘Invisible Hand’ of Floral Chemistry,” Science, 29 August 2008: Vol. 321. no. 5893, pp. 1163-1164, DOI: 10.1126/science.1163570.

The authors presumably presume that Darwin’s mechanism could achieve the mutualistic symbiosis.  Creationists might agree that natural selection could intensify the symbiosis, leaving behind only the most capable at it in the harsher post-Flood environment, but how the symbiosis arose in the first place is a different matter (cf. 02/26/2007).  Plants possess an astonishing chemistry set.  They can produce hundreds of complex organic molecules with finely-tuned signals for the animals they need (see 02/21/2006).  Other molecules “talk” to nearby plants or deter predators (see 04/26/2007).  Organic chemists would have a major challenge duplicating this feat.  These molecules don’t just “emerge” or “arise” (favorite Darwinist words) by undirected processes of chance.  They are coded in the genes.  Put that in your pipe and smoke it.*

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