Absent Caterpillars

I saw (and Blipped) some identical webs almost exactly two years ago, at precisely the same location. On that occasion they were covered in caterpillars, which with help from the Blip community, were eventually identified as ermine moth caterpillars. No sign of the caterpillars today though.
It’s a place I pass regularly on bike rides, and I’m sure I didn’t see any sign of webs last year, but here they are back again on the same two metre length of hedge.