|Grabbing pollen - Linda Bower|
This "wasp" is actually a male Thick-headed Fly, Physocephala tibialis, of the family Conopidae. Most of this family are convincing mimics of thread-waisted wasps (Sphecidae). They feed on nectar and like bees gather pollen incidentally.
|Thick-headed Fly, Physocephala tibialis - Molly Jacobson|
"This is no ordinary fly! As a parasitoid, this species of Thick-Headed Fly (no common name) deposits its eggs into Bumblebees. It catches the Bumblebee mid-flight, sometimes falling to the ground, the fly inserts a single egg between its abdominal segments. The larva will slowly eat the Bumblebee alive, beginning with the non-essential tissues first. The larva forces the Bumblebee to dig itself into the ground so it can overwinter as a pupa (this is called adaptive manipulation). Adults feed on nectar, as shown in this video of a male filmed on Common Milkweed in the Missouri Ozarks, USA, June 27, 2017. Some clips are in slow motion, none have been sped up."
|Stylogaster sp. of thick-headed fly with long ovipositor - MJ Hatfield|
There are a lot of interesting details about how the fly cuts its way out of the pupa and how the bee is tricked into burying itself in the ground. (Hint - it is adaptive manipulation). I would explain that, but our friend the Bug Lady does it much more entertainingly in this UWM Bug of the Week blog.