ECOLOGY:
Mutual Nonaggression Pact May Aid Ant Spread
Evelyn Strauss
Argentine ants have become common pests worldwide. Researchers have thought that one reason the invaders flourish is because they lose some of their natural aggressiveness against their own kind. Work reported on page 949 now provides the first direct evidence for that idea. It shows that pairs of Argentine ant colonies that don't fight reach higher population numbers than pairs of warring colonies, possibly because the peaceful ants waste less time and energy. The new findings may spark ideas about how to control Argentine ant invasions.