Monday, July 17, 2017

Pasting Pollinators

 
Text and photos by Nancy Partlow©
 
Neon-pink flowers are in currently in bloom along the  East Bay waterfront.  I didn't know what they were until  following the theory of, "to find bees, go where the flowers are",  I decided to check them out. I was delighted to discover that these blossoms are a terrific  food source for pollinators.   


Lathyrus latifolius, or  Everlasting Pea, is a widespread naturalized wildflower that blooms in shades of white to deep pink.
 
Lacking the heady scent of the bred-for-garden sweet peas, the flowers are nonetheless similarly beautiful. 
 
Queen Bombus vosnesenskii on wild pea flower.


The sturdy blooms attract a variety of pollinating insects with their nectar, predominately bumble bees, including a noticeable number of bombus queens of various species.
 
Honey Bee
Hoplitis bee

  
Cabbage white butterfly

Bombus melanopygus queen

I was glad to see  Bombus fervidus using these flowersNot one our most common, generalist bumble bee species B. fervidus instead seems to prefer particular plants, including, apparently, Everlasting Pea.  
 
Bombus fervidus
 
While taking pictures one day, I noticed a big blob of pollen near the head of a Bombus fervidus worker, which I thought very odd.  That is not where the pollen is supposed to go.   Was this an inept bee that didn't know where to store its pollen?  That seemed unlikely since bees are evolutionary experts at what they do.   


The mystery was solved only when I pulled up another image of this bee on my computer.  The stamens on these pea flowers, which remain hidden until a bee pushes its head into a blossom, sneakily pop up and paste it with pollen right at base of its wing. Since that is a hard-to-reach place for the bee to groom, the pollen stays there. 


This video shows the mechanism at work:

https://www.youtube.com/watch?v=7B7s9rQ8lTY

Other bees are similarly dusted and smeared.

Hoplitis leaf-cutter bee
  
Western Little Leaf-cutter Bee

 
On this Bombus sitkensis the stamen looks like a tiny spatula slathering buttercream frosting on the bee. 
 
Bombus sitkensis




Blossom by blossom, pollen-pasted bees fertilize the pea flowers.   It's a clever strategy for this plant, and if the East Bay waterfront is any indication, a very successful one!
 
Since it's such great pollinator attractor, I considered gathering some pea seed for my yard, but reluctantly decided against it due to the plant's somewhat robust spreading habit. However, I think East Bay is perfect place for it, and I can only hope these gaudy pink wildflowers and their feasting bumble bees endure at this location for many years to come.
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