Mistaken Identity on a Goldenrod Flower 🌼

One Goldenrod, Two Bees, and a Misunderstanding

I was surveying a patch of showy goldenrod in my yard, diligently recording through EwA Buggy each arthropod in a square-meter plot: its size, activity, interactions, survey effort, the weather, leaf damage, you name it. Then I spotted him. He was covered in pollen, looking rather stout, and clinging to a flower head with all six legs as though his life depended on it. A moment later, he launched himself clumsily toward another bloom, apparently ready for a second nectar gulp.

A beautiful, healthy male eastern carpenter bee (Xylocopa virginica): big, glossy black, and equipped with enormous eyes that nearly meet at the top of his head. In a later photograph, I caught the other telltale mark, the pale yellowish facial patch on the clypeus that males carry. Male carpenter bees have no stinger, so perhaps they compensate with bravado, patrolling their small territories and investigating anything that moves. This fellow had plainly been working the goldenrod for some time. Pollen dusted him from head to thorax, the kind of golden coating earned through determined, sustained foraging.

Then I understood why he looked so big!

Tucked beneath him, gripping his abdomen with legs and mouthparts, was a second bee. Smaller and fuzzier, it initially looked as though it might simply be riding along, perhaps even held by the carpenter bee himself. It was hard to tell who was who, or what exactly was happening, beneath all those pollen grains. But the longer I watched, the clearer it became that the grip ran the other way entirely. The second bee, a bumblebee, was holding on, and holding tight. Whatever the carpenter bee did, whether feeding, shifting his footing, or even taking off, his passenger remained firmly in place.

My first thought was a territorial dispute, two bees squabbling over a particularly fine patch of goldenrod. But the more I considered it, the less that explanation held up. I do not know of male Bombus defending floral patches against other species in the way male carpenter bees are known to defend territories. So I went looking for other clues.

I got close enough to check for a corbicula, the smooth, shiny pollen basket on the hind tibia that female bumblebees use to carry pollen back to the nest. There was none, only loose grains caught in the bee’s hair, the incidental dusting one would expect on any flower visitor rather than a provisioning load. I also tried to see his face. Males often have longer antennae and species-specific facial markings that can help distinguish them from females or workers, although the view did not allow a definitive identification. Taken together, the clues suggested a male bumblebee, perhaps a common eastern bumblebee (B. impatiens), one of the species still active on goldenrod well into September in the Northeast.

The missing pollen basket turned out to be central to the story. Male bumblebees do not provision nests. Late in the colony cycle, their principal reproductive role is to find and mate with new queens. Bumblebee mating commonly occurs on vegetation or the ground, and males can remain attached for extended periods. In some documented cases, queens have even flown with males still attached.

Nothing here was predation, and the two bees were not reproductively compatible. What I had likely witnessed was a case of mistaken identity, with a determined male bumblebee attempting to mate with a much larger bee from an entirely different genus. He did not let go, even when the carpenter bee took flight with him still attached, an uninvited passenger along for the ride.

It is a good reminder of what a square-meter plot can reveal if you sit with it long enough. I love Buggy for that. It forces me to slow down radically and observe intently. Since I began using it, I have noticed so many details that I once would have walked right past. It is a genuine scientific tool, but also, in its own small way, an enactment of Mary Oliver’s instructions for living a life: “Pay attention. Be astonished. Tell about it.” Well, I just did.

📷 Eastern Carpenter Bee · Xylocope Orientale (Xylocopa virginica) | © Claire O'Neill; please credit accordingly.