Last night I discovered many ants entering my house through a window with an imperfect seal. I placed a poison ant bait on the window sill and within seconds they were feasting on it. This morning I noticed there were still many ants near the bait, but they were all bypassing it as if they were somehow warned to stay away. Do they have such a signal? If so, how would they know the bait is a problem? If not, what could cause them to be so interested last night and not interested at all today? (I can see that there is still plenty of food inside.)
Update: after a little bit more research, I decided that ants do not have a "stay away" signal, and that the only explanation for ignoring the bait would be a stronger scent trail leading somewhere else. Last night when I opened the window I found the jackpot. There was some sort of sticky substance all over the bottom of the window, and hundreds of ants celebrating the find. My conclusion is this was much more attractive than the bait, even though it was merely an inch away from their path.