Crop Protection
January 24, 2009
The scientific study, conducted at the University of Wuerzburg in Germany, showed that insecticides, which can be highly toxic to humans and alter ecosystems, were bested by bee swarms when it came to ridding gardens of insects.
The bees were found to chase away insects that were likely to eat pollination buds.
Caterpillars are particularly sensitive to bees since the buzzing of the insect's wings irritates the sensitive hairs on their bodies.
The German scientists found that caterpillars stopped moving or simply dropped off the plant they were feeding on if an "unidentified flying object" approached generating air vibrations of the right frequency, said Dr Jurgen Tautz from the Wuerzburg research team.
Constant stress from buzzing bees foraging for nectar caused caterpillars to feed a lot less, said Tautz.
Herbivore-fighting bees
The German 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 around 70 percent less damage to their leaves than those without bees. "Our findings indicate for the first time that visiting honeybees provide plants with a totally unexpected advantage," the German researchers reported in the journal Current Biology.
"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, Dr Tautz said.
He said the finding could mean that bees could have a practical application in sustainable agriculture.
His team now plans to investigate whether combining crops with bee-attracting flowers can improve yields in areas plagued by leaf-eating pests.
"Our finding may be the start of a totally new biological control method," said Tautz.