I learned a few things about their behavior including one thing I stated in this post here:
Food chewed off quickly allows each ant return faster to the nest, bringing out more ants at a much faster rate than food chewed slowly.Apparently this discovery has been proven by Stanford Scientists Debora Gordon et. al. and restated in a lot more words in this press release:
Gordon has found that the rate at which harvester ants ... leave the nest to search for food corresponds to food availability. A forager won't return to the nest until it finds food. If seeds are plentiful, foragers return faster, and more ants leave the nest to forage. If, however, ants begin returning empty handed, the search is slowed, and perhaps called off.
Harvester ants. Creative commons photo: Steve Jurvetson
Here is the link to an actual paper, and the words from the paper restating the above:
Regulation depends on feedback from returning foragers, who stimulate the outgoing foragers to leave on the next trip. Forager return rate corresponds to food availability, because foragers almost always continue to search until they find a seed, then immediately bring it back to the nest. The more food is available, the less time foragers spend searching and the more rapidly they return to the nest.