On the same spot where I observed a male Chyromya some time ago appeared four female Chrysomyidae flies during a period of about two hours, two of which were present simultaneously. The species cannot be determined, see also:
The big question is why the flies are drawn to this specific spot. They seem to just sit still on an Ivy leaf mostly with the head pointing in the direction of the plant. Every now and then they’ll fly up or away. They are skittish when larger wasps fly by, and sometimes they will flee to the back of the leaf and hide there.
One female flew deep in the dark of overhanging leaves and twigs of the plant mass next to the Ivy and seem to gradually approach the plant from the side but eventually landed on a leaf and remained there. Hopefully this mystery can soon be solved!
This particular spot of greens presents a funny situation since it includes these flies, all Chrysomyidae group species are currently categorized as very rare in the Netherlands, and the very rare wasp Bethylus boops, for which I am trying to figure out what they are doing as well.
Makes life a bit easier 😂
The photos show three specimen.