Breaking and Entering

This week’s bee is short and sweet: it’s an Andrena, a mining bee, and a relative of the bees nesting in the alley behind my house.

It’s doing something very unusual.



The flower it’s on is Solanum crispum.  In the garden stores they call it Chilean potato vine, which is fine (it is related to potatoes), but I prefer Chilean nightshade (for the same reason.)  Like most nightshades, it keeps its pollen rolled into a tiny packet in the middle of the blossom.  In order to get the pollen out, a pollinator has to shake the packet at something close to its mechanical resonant frequency, a musical habit called “buzz pollination”.  In the Pacific Northwest, the only bees large enough to pull off buzz pollination are bumblebees.


If you look at what this bee is doing, she has wedged two of her legs inside the pollen packet, and is using them as levers to break the packet open.  The packet isn’t letting go – you don’t see the “puff” of pollen that is characteristic of successful buzz pollination – but she is able to pull some pollen out.

Now, I have no idea whether or not this approach to pollen gathering can actually fertilize the flowers.  The vine is not self-fertile, and I haven’t seen any others in the area.  Even if there were viable pollen in the neighborhood, this may just be an unusual case of “pollen robbing”.  (Nectar robbing is much more common.)

Still, it’s pretty cool.  As far as I know, until I brought this photo in, no one knew that the local mining bees could do this.

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