Ant Colonies have Personalities

Yet another way that ant colonies resemble organisms:

To determine how group behavior might vary between ant colonies, a team of researchers led by Raphaël Boulay, an entomologist at the University of Tours in France, tested the insects in a controlled laboratory environment. They collected 27 colonies of the funnel ant (Aphaenogaster senilis) and had queens rear new workers in the lab. This meant that all ants in the experiment were young and inexperienced—a clean slate to test for personality.

The researchers then observed how each colony foraged for food and explored new environments. They counted the number of ants foraging, exploring, or hiding during set periods of time, and then compared the numbers to measure the boldness, adventurousness, and foraging efforts of each group. They also measured risk tolerance by gradually increasing the temperature of the ants’ foraging area from 26°C to 60°C. Ants that stayed out at temperatures higher than 46°C, widely considered to be the upper limit of their tolerance, were considered risk-takers.

When they reviewed their data, the scientists found strong personality differences between colonies, they reported online this month in Behavioral Ecology. Some were bold, adventurous risk-takers with highly active foragers. Others were shy, risk-averse, and fearful of new environments. Their foragers were less active, and they were less inclined to search for food at very high temperatures. When the team performed the same tests 11 weeks later, they saw that these differences persisted over time.