In early July, 2005, we walked along the bank of the lower Elwha river on a sunny day. This is an interesting environment: this beach is on the river, but quite close to its mouth into the Strait of Juan de Fuca. (delta | beach)

As we walked, we saw a bee which seemed to be carrying something. We stopped and watched it until we saw it land near a rock (upper left). We crept up on the rock, but couldn’t see the bee.

Gently lifting the rock, however, revealed a bee “working” in a hole in the sand (upper middle). Note the two circular bits of leaf, the bee’s hairy hind end and the pollen blob on the bee.

The top-right image is a close up of the hole the bee was in. You can see bits of leaf on the walls and blobs of yellow pollen. We took a short QuickTime movie of this bee as it continued to work the hole (lower left, 1.2 MB), finally emerging and flying away. At the very end of the movie, note that the bee’s wingbeats create enough downdraft to flip a bit of leaf over.

On returning home, we consulted our references while viewing the images and movies. This is a Leafcutting Bee, (Family Megachilidae), which typically line her egg-laying chambers with bits of leaf, and separate egg chambers with circular pieces of leaf. According to Boror, Delong and Triplehorn, An Introduction to The Study of Insects, 4ed, “It is not uncommon to find plants from which circular pieces have been cut by these bees.” As you can see in the last image above, we did find a Bigleaf Maple with leaf cutouts that exactly matched the circular bits of leaf we saw under the rock. Leafcutting bees gather pollen, carrying it on the abdomen (unlike honey bees, which carry pollen on their legs). Simple pollen-carrying hairs are called a scopa, from the Latin for broom. Honey Bees have specialized pollen baskets. This Leafcutter’s scopa is briefly visible in one of the last few frames of the video. (Here’s a photo of a scopa full of pollen on a megachilid photographed at the Dungeness Wildlife Refuge 09 14 06.)

Part Two, The Cuckoo | Another Leafcutting Bee | Yet Another Leafcutting Bee