From last weekend's observations...
I was just out by my hives watching the girls bringing in pollen on this next to last day of September. It's sunny and warm, a late afternoon, about 85F degrees outside.
Asters, some clover and goldenrod are in bloom in my yard; otherwise there is a dearth of flowers available, as it is very dry and we've had no rain. I see the girls are especially fond of a small purple aster near to my house's back door, and along with bumble bees and wasps and sweat bees, they are all over this stuff for the pollen.
I watch the beeline back and forth from the two healthy hives to these asters. It's a very predictable pattern.
I soon see someone else has noticed and figured this out as well. A European hornet, the largest North American hornet we have (see image below), is hovering in front of the first hive looking for an opportunity. With horror, I watch as it nabs one of my hardworking girls, with full pollen sacs, right out of midair as the worker is returning from the asters to the hive!
My little worker struggles and flaps violently as she tries to break loose, but the hornet has a good grip on her with its mid and forelegs. The weight of the bee is causing the hornet trouble flying, and she pitches, rolls and yaws as she tries to fly to a stationary object where she can eat her early evening meal. She lands with her hind legs on a nearby birdhouse. I creep up secretly to watch; and momentarily, I consider releasing the worker! But then, I quickly remember how painful a European hornet sting has been reported to be.
The hornet starts on my worker's head and thorax. Even headless, my little worker is still flailing her wings and legs. Oh, this is horrible! I can't watch; and yet, I wish I had my camera with me to document this. The hornet has large muscular mandibles and picks away at her flesh; little bit by little bit. Then, it tires of the birdhouse perch and decides to fly with only my worker's abdomen remaining; it goes up to a higher roost in the silver maple tree. I lose sight of them in the dappled sunlit leaves.
Wow! I don't know where this European hornet's nest is located, and I see no other hornets currently, but I hope they don't all decide to come over to my hives and feast! Of course, the worker hornet no doubt has already communicated (with pheromones) its find; and that information has been passed along now, and it may soon be happening. Fortunately, it will soon be nightfall. Then, I remember an obscure fact from Entomology 101 class. European hornets are the only hornets that can fly at night...but, usually to porch lights, and there are thankfully no lights near my hives!
Photo image from wikipedia, European hornet