Copulating pair of Taeniaptera trivittata, a type of still-legged fly (Micropezidae). Males (or females, according to one source) apparently brush the eyes of the partner during mating, though this frame didn’t capture that. When flitting around leaves they wave their white-tipped forelegs and look just like small ichneumon wasps. They have thin waists but the pattern on their wings makes them look even thinner, waspier. Known to feed on rotting Typha, which was abundant nearby (John Heinz National Wildlife Refuge, Tinicum, PA).
If you come across a pair, please take a video so I can see the legs in action. I like to watch, and I know of others who are interested in this species.
Here are a few photographs of kleptoparasitic flies stealing hemolymph from a praying mantis dining on a pentatomid. They might be Milichiella arcuata or M. lacteipennis, types of jackal flies, but those are just guesses. Jackal flies (Milichiidae) and frit flies (Chloropidae) are commonly found on dead insects, but the volatiles released by dismembered true bugs are apparently especially attractive (see Zhang and Aldrich 2004). And if you search online for images of jackal flies, they also seem to be common on dead or dying honeybees, so presumably bees exude a volatile that is attractive to flies as well. I’d love to find an article that times the arrival of various kleptoparasitic flies at different types of insects … could use the assemblages to give approximate time of death, I’m sure, just like on CSI. I don’t watch CSI, so I’m guessing here as well.
Just a silly little graphic I made for a friend coordinating a blood drive … with the idea that a sticker might be made for donors:
I also wrote a silly little blurb, though I’m sure the math could be improved upon:
“Some people might be hesitant to donate blood if they haven’t done it before, so I just wanted to remind everyone that they have, indeed, donated blood before: to mosquitoes. A typical mosquito (always a female, by the way) flies away with 0.001994 mL per meal, at least according to an article from 1937 on blood loss in horses. Not so much, perhaps, but it adds up when her friends find you, too, and they do. So you’ll donate a pint of blood after being visited by 237,212 of the little beasties. Much easier to just sign up and be done with it in 10 minutes. And it won’t itch when you are done!”