I’ve been wondering if bees sleep since I saw all these black bees zooming about in the early evening. They seemed to be chasing each other. Then they clustered on a few stalks of grass, jostling and fighting for the good spots, until they finally settled down.
When I looked them up, I was told they were Melissodes bimaculata in a male sleeping aggregation.
They were asleep?
The short answer is yes.
According to this paper about sleep in honeybees (try your library for access to the full text), honeybees have sleep cycles. As they pass from light to deep sleep, their antennae droop, their legs relax, their body temperature drops, they get harder to rouse.
Just like this bumblebee that I found a few weeks ago, curled up on a sunflower on a sunny morning. She seemed a bit groggy as she bestirred herself, took a sip of nectar, and eventually flew away. And lately, I’ve been finding bumblebees bedding down for the night on the goldenrod.
As for the black Melissodes, they’re solitary bees. The females, having tunneled into the earth and provisioned cells for their eggs, have underground nests to sleep in. The males gather together to roost. (Apparently, lots of insects roost overnight.) Then they lock their jaws around the stems and go to sleep.
This is so cute and so weird. Next I suppose, it will turn out that they dream, too.