Trail mix: espionage among the bees

Science News, July 24, 2004 by S. Milius

Some bees rely on olfactory spying to capitalize on other bees' hard work, researchers report.

When certain bees find food, they mark the trail for their nest mates by leaving odiferous chemicals on leaves and other stopover points during the flight home. In an outdoor laboratory setup, James C. Nieh of the University of California, San Diego and his colleagues examined foraging behavior of an aggressive Brazilian bee, the stingless Trigona spinipes. Its foragers spy on another Brazilian stingless species, Melipona rufiventris, the researchers report in an upcoming Proceedings of the Royal Society of London.

When the researchers monitored T. spinipes bees where they habitually fed, the insects paid attention to scent marks of their nest mates and generally ignored marks left by M. rufiventris. But when T. spinipes bees were foraging for new sources of food, they were most attracted to scents from M. rufiventris.

This chemical espionage can pay off. In six trials, T. spinipes bees attacked foraging M. rufiventris bees and took over their food.

Such spying clashes might have pushed bees to evolve an alternative to scent trails, Nieh speculates. Honeybees, for example, reveal food locations during dances performed at their nests.