Many dance flies present prey as nuptial gifts as a part of their mating rituals, but as Powell and Hogue write in California Insects, "The strangest habits are exhibited by a few species in which males secrete material from the digestive tract which is formed into a frothy, white ball or "balloon". This balloon either entraps a small prey or is substituted for prey in the courtship gift-giving sequence" (p. 161). This balloon clearly has prey within, perhaps some kind of hemipteran.
Ron and I were pretty flabbergasted as we watched these two engage in mid-air copulation, their aerial control so perfect that I was able to get this picture even though each fly couldn't have been more than 7 mm long.
Jack Owicki has this great BG photo that spawned an even greater discussion: http://bugguide.net/node/view/267952/bgimage.
I suspect this is Empis and not another genus in Empidinae due to the balloon-forming behavior and the long proboscis, but I'd love correction! Habitat was very close to a running creek, vegetation was riparian, some willow, but mostly oaks and maples.
Spotted one of these tiny spiders on a leaf below me, then saw another. They seemed to be signaling each other, came closer together. I took as many photos as I could before they disappeared. On the computer I could see that one had offered the other an ant.
Powdered Dancer
Argia moesta
pair in copula
with a bee fly (Toxophora virgata) of the
Family Bombyliidae perched
on the abdomen of the male damselfly.
near Laguna Dam,
Yuma Co., Arizona
6 October 2013
Image of bee fly as well as image of the whole scene posted. Nature Ali, finatic, and I all took shots of this as well as perhaps others. Link to Bugguide ID also posted.
http://bugguide.net/node/view/852303
I posted the Powdered Dancer record earlier at:
72 cm long
Green Tree Ant (Oecophylla smaragdina)
D. maculata emerging from it's cell
AKA Common Bluewing. I believe this is the only Zenithoptera that occurs in Costa Rica.
We had a great day for this species and probably saw a dozen or more. They are powerful and large predators. Image 1 shows a male hovering briefly near a female. The male was following the female around and when she would perch he would hover nearby and attempt to mate, but she would take off. Finally she landed near me and I focused on her and the male hovered briefly and I got one shot before they took off again.
Pareja de sírfidos apareándose en vuelo estático. En esta fecha había una gran cantidad de especímenes en la zona
Two pairs in tandem with females ovipositing in rotting wood.
River Trail Park,
Luling,
Caldwell Co., Texas
22 July 2016