In the 20 years since we built our home, we've just recently had our first ant infestation.
I'm familiar with the fact that ants leave scent trails to find their way back and forth between the colony and a food source. So in my limited experience with ant eradication, I assumed that by taking away the empty ice cream bowl and scrubbing the scent trail which lead to it off the kitchen counter (multiple times with different household cleaning products) the ants would quickly give up their search.
My assumption was that the oncoming foragers would be confused by the abrupt end of the scent trail and wander aimlessly in the gap between where the trail had been scrubbed away and the former location of food.
However, what I’ve observed again and again is ants continuing to move across the scrubbed counter to the exact location of where the food used to be -- as if they didn't need the scent trail. Their only confusion seems to be the lack of food at that spot. This behavior will continue for several hours after the removal of whatever food had been there, despite multiple eradications and vigorous scrubbings of where the original trail had been.
Ants follow odor plumes to food sources according an answer in another Biology Stack Exchange post. (Can ants sense food from a long distance?)
And from a link in the same Biology Stack Exchange post “If they [patroller ants] didn’t return to the nest, departing foragers would know it wasn’t safe to go search for food.” and “The ants can take advantage of sudden windfalls of food, but they don’t waste energy and resources if there’s nothing there.” (https://wikkorg.wordpress.com/2015/04/23/ants-swarm-like-brains-think/)
Here are my questions:
Are ant scent trails strong enough to withstand multiple washings with soaps, detergents and disinfectants?
Can ants detect airborne food molecules in very small parts per million, even after the food and its odor plume have been removed? If not, do ants use something similar to the honey bee "waggle dance" to instruct the rest of the colony where to find a food source? Or both?
Why and how do they keep coming back to a place where there is no food, especially if (eradicated) members of the colony are not returning?