Awesome zoology discovery* of the day: the cuckoo bumblebee!
They are a specialized lineage which has lost social behavior, and lost the ability to collect pollen, and are instead cleptoparasitic in the colonies of other bumblebees. Before finding and invading a host colony, a Psithyrus female (there is no caste system in these species) will feed directly from flowers. Once she has infiltrated a host colony, the Psithyrus female will kill or subdue the queen of that colony and forcibly (using pheromones and/or physical attacks) “enslave” the workers of that colony to feed her and her developing young.
Okay, it’s also sort of sad, because bumblebees are adorable. (Just say it to yourself and try not to smile: ‘bumble’.) But it’s also weird and wonderful and unexpected. I love this stuff.
*For the limited sense of ‘discovery’ that means ‘I didn’t know this until I read it on the internet, but the scientific community has known it for more or less ever.’