90% of returning foragers are “successful”. Therefore, forager return rate is a good indicator of food availability. Logically, overall foraging activity is influenced by the rate of returning foragers. When food is plentiful, foragers quickly find it and immediately return to the nest. Foragers still in the nest interpret this to mean food searches will be profitable: low energy input with a high chance of a seed reward. Foraging activity consequently is increased. Likewise, a decline in food availability, indicated by a decrease in forager return rate, causes the colony to decrease its foraging activity. The ability for a colony to quickly regulate its foraging behavior is quite important since their food source is variable and scattered. This regulatory ability is variable in itself, influenced by food availability, current need to eat, and colony health. Colonies are more likely to adapt to varying forager return rates when the rate of foraging is high, which may be because variances are simply harder to detect during low rates. Overall, the red harvester ant demonstrates a remarkable ability in social cognition, cost-benefit analysis, and behavioral economics. Collective regulation Harvester ant populations operate without a centralized control system by means of a decentralized chemical communication system, through the process of chemical signalling. Foraging is regulated using positive and negative feedback loops. Ants returning to the colony stimulates outgoing foraging. When ants return to the colony at a higher rate with seeds, this in turn causes the outgoing rate of foragers to increase. As fewer ants bearing seeds return to the colony, the rate of outgoing foragers decreases. The result is foraging regulation relative to the abundance of available food at any given time. The interactions between returning and outgoing foragers operates on a timescale of seconds. It typically only took three to eight seconds for an outgoing forager to leave the nest as a result of an increase in successful returning foragers. Relative abundance of food available is gauged by the average time spent foraging per seed, rather than the distance traveled to find each seed. Foragers take less time when food is more abundant. Faster foraging signals faster rates of outgoing foragers, maximizing the harvest of food relative to the abundance in the area. Seeds are used as a source of water for ants, and are often kept in the nest for a few months to several years. Interference competition in foraging Interspecies