Saw these bugs inside the flat I'm renting (Switzerland), but I really can't figure what kind they are. What I can say about them:
- They can do small jumps (up to 5cm I would say). It doesn't seem to be for locomotion, but as a means of escape when I try to catch one.
- Size: about 1.5mm for the "big" ones. There are of various sizes down to 0.25mm for the really tiny ones (approximately; never managed to get one without crushing it). They behave much the same as the big ones (including the jumps) and are whiter in color.
- They don't seem to live as a colony or in a nest (or I simply didn't find it), but sparsely on the wood floor, often near the baseboards. Found some on the walls, but those were the exceptions. They don't seem to like the bathroom.
- Rather delicate; can easily be crushed.
- Seem more active in the evening and at night, but don't mind going out during the day.
- I live alone, without pets, but I don't remember having been bitten. I guess they don't feed on blood.
- Seem to have long antennas (about half their body size) and small wings.
Side note: the flat is on the 3rd floor of a recent building (finished 14 months ago). I'm the first tenant.
An exterminator came and quickly classified them as some kind of flea. He put some pesticide on the baseboards, and their number is now quickly decreasing. But I'm still curious.
My first thought was "fleas" (because of the jumps), but I deemed them too squishy and not "vampire" enough for that. Also, I don't think that (what I assume to be) the young ones should be able to jump.
Then I thought "springtails", but I didn't see any furcula (granted, I don't have a good eyesight) and I don't think they are supposed to have wings.
One of them was nice enough to jump on some tape.
Top (on a ruler):
Also, blowing on it (to open the wings):