Athena Rayne Anderson

This content is based on a post originally published on July 23, 2011, on my blog “Pollinators Info” (no longer online).

The fly in this photo is carrying pollinia on its right middle leg- they’re the orange things at the black arrow. The wasp in the featured image has pollinia stuck to two of its legs (they’re yellow-orange).

Here’s a fun analogy: think of a blackberry flower as a convenience store in which any pollinator can enter to buy pollen and / or nectar. A milkweed flower is like a convenience store that only sells nectar, but sticks a locked backpack full of pollen on you before you leave. You don’t have the key to the backpack, and the only way to get rid of it is to go into another convenience store of the same kind!

Sounds like it would be hard to get your pollen around this way, doesn’t it? One of the costs of using pollinia for the species that have them (including orchids) is that not all flower visitors will carry it around for you. But the huge benefit is that the visitor can’t destroy the pollen by eating it! This means that the milkweed invests more energy into each pollen grain and produces fewer grains for relatively the same amount of energy as a blackberry flower that produces many more grains, but invests less energy in each one. It’s analogous to different reproductive strategies in animals: some produce thousands of eggs and don’t take care of them (like salmon), while others produce only two offspring at a time and invest a lot of energy caring for them (like people).

Tell us about your experience with other plants that have pollinia! Can you name some I didn’t talk about here?

Featured image copyright peterwchen, 2014 CC BY 4.0