The Carnivorous Plant FAQ Field Trip Report -

Darlingtonia pollination studies in 2006

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A few more:
Stephen and I saw several cases in which Andrena entered Darlingtonia flowers, and we captured more individuals. They were also very active in pollinating the Vaccinium at the site. I found that that easiest way to capture the bees was to simply look around for one of them (usually working the Vaccinium plants), and then trail after it. As one of the bees wandered from flower to flower, a trip to a Darlingtonia flower was nearly an inevitability. I never saw how they exited the flower, but Stephen said they dropped out from the bottom of the flower.

A few days later, I returned to the site. In the intervening days, most of the pollen from the Darlingtonia had been harvested. Neither European honeybees or Andrena were to be seen anywhere, even though I was there at the same time of the day as before.

Is it possible that Andrena nigrihirta is the primary or even exclusive pollinator? It is hard to say. And I can't even say for certain these bees were actually transferring pollen from plant to plant. Elder (1997, p27) reports that one day she observed an Andrena bee (she does not state the species) enter a flower, and she captured it and found Darlingtonia pollen on its body. Upon laboratory examination, I could not find pollen on the Andrena I collected. However, I had kept them alive in mesh baggies for several hours before I examined them; perhaps the pollen was removed from the bees in the interim, by some mechanism I do not know.

Despite introducing so many new questions, this certainly was a memorable day filled with interesting observations!

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Revised: October 2007
©Barry Rice, 2005