Bees scare off plant-munching caterpillars
Published Dec 22, 2008
By John von Radowitz, Press Association Science Correspondent
Honeybees protect the plants they pollinate - by telling hungry caterpillars to buzz off, scientists have discovered.
The bees' buzzing puts the wind up the caterpillars, which have body hairs sensitive to air vibrations.
Unable to tell apart a harmless bee and a predatory wasp, the leaf-munching larvae are frightened away.
Researcher Dr Jurgen Tautz, from the University of Wurzburg in Germany, said: "These sensory hairs are not fine-tuned. Therefore, caterpillars cannot distinguish between hunting wasps and harmless bees."
Studies had shown that caterpillars stopped moving or dropped off the plant they were feeding on if an "unidentified flying object" approached generating air vibrations of the right frequency.
Constant stress from buzzing bees foraging for nectar caused caterpillars to feed a lot less, said Dr Tautz.
The scientists conducted an experiment in which bell pepper plants were kept in tents with either bees and caterpillars or caterpillars alone.
Plants surrounded by buzzing bees suffered between 60% and almost 70% less damage to their leaves than those that were unprotected.
The researchers reported in the journal Current Biology: "Our findings indicate for the first time that visiting honeybees provide plants with a totally unexpected advantage.
"They not only transport pollen from flower to flower, but in addition also reduce plant destruction by herbivores."
The findings highlighted the way apparently unrelated members of food webs interacted in nature, said Dr Tautz.
He thought they may have a practical application in sustainable agriculture.
His team now plans to investigate whether combining crops with flowers that attract bees can improve yields in areas plagued by leaf-eating pests.
"Our finding may be the start of a totally new biological control method," said Dr Tautz.