Wasp Killing Machine. (Remake of a video from 2008) No-fly zone

In the beginning the wasps flew directly to the wire without hesitation. Now there seems to be a change in the behaviour in the remaining population. Instead of flying directly into the wire, they are now more hesitant. Many of them seem to be attempting to avoid the wire. How can this change in behaviour in the remaining population be explained? Most likely a wasp can see the wire better than humans can. But how is the association with the wire and danger established? Distributed by OneLoad.com