On squash pollination

Members of the family Cucurbitaceae have some of the largest pollen grains known.  These spiny spheres are designed to stick to insects…squash flowers of all sorts are entomophilous and require insects to move their pollen from male to female flowers.  But most bees that visit squash flowers don’t seem to like the pollen very much.  I have watched honeybees and bumblebees land on nearby leaves to clean the pollen off instead of into the baskets on their legs as they normally would on a pollen foraging trip.  They seem to only visit squash flowers for the nectar.

That’s why the squash bee, Peponapis pruinosa, is so interesting!  The squash bee collects only pollen from members of the plant family Cucurbitaceae.  Why does it specialize on this pollen that is so unwanted by the other bees?  A great question.  😉


Honeybee drinking nectar


Honeybee cleaning squash pollen off its body and onto a leaf


Just a pretty photo (IMHO)


Not a great photo, but you can see how she is smearing the pollen onto the leaf.


Bumblebees get COVERED in squash pollen


But they also land to clean it off

IMG_6552 IMG_6557Specialists are so fascinating! Squash bees LIKE squash pollen, but why?

"I'm a mystery!"

“I’m a mystery!”


11 thoughts on “On squash pollination

  1. Very kewl captures of the buzzy bees + a cucumber beetle to boot!
    I always wonder about specialty bugs. To think you only have one plant to either eat, use or reproduce on… You’d wonder how they survive! ? Alas, life goes on!

  2. Interesting. One of the few monolectic bees in the UK is Andrena florea, which gathers pollen from our only native cucurbit, Bryonia dioica:

    Andrena florea female - Milford Common, Surrey 2014d

    Is there something about the cucurbits that promotes the evolution of monolecty, I wonder?

  3. Really interesting. I wonder if this applies to the Malvaceae too. Bumble bees get covered in the Malva and Hibiscus pollen and seem to brush it off yet their are Malva specialist bees. Mmm. Amelia

  4. Pingback: Misty morning in the squash fields | standingoutinmyfield

  5. Pingback: Little pollen sausages | standingoutinmyfield

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