Bee buzz might be a good biological weapon against insects feeding on plants

Daily mail reports that the flowers use bright colours and strong scents to attract honeybees to their pollen. But the stripy insects also defend them from other insects, according to a new study in Current Biology. Their buzzing noise warns off others such as caterpillars who would otherwise munch on the blooms undisturbed.

The researchers, led by Jürgen Tautz from Biozentrum Universität Würzburg, Germany, found many caterpillars possess fine sensory hairs on the front portions of their bodies that enable them to detect air vibrations, such as the sound of an approaching predatory wasp or honeybee. 'These sensory hairs are not fine-tuned,' Mr Tautz said. 'Therefore, caterpillars cannot distinguish between hunting wasps and harmless bees.' If an 'unidentified flying object' approaches, generating air vibrations in the proper range, caterpillars stop moving or drop from the plant. If caterpillars are constantly stressed by buzzing bees, such as in blossoming fruit trees they will feed a lot less, he said. In the study, the researchers found that bell pepper plants without fruit suffered 60 to almost 70 per cent less damage to their leaves when confined in a tent with bees and caterpillars in comparison to those in a tent with caterpillars alone. 'Our findings indicate for the first time that visiting honeybees provide plants with a totally unexpected advantage,' the researchers said. 'They not only transport pollen from flower to flower, but in addition also reduce plant destruction by herbivores.' The findings highlight the importance of indirect effects between apparently unrelated members of food webs in nature, Tautz said. They might also have some practical application for sustainable agriculture.

If crops are combined with attractive flowers in such a way that honeybees from nearby beehives constantly buzz around them, it may lead to significantly higher yields in areas with lots of leaf-eating pests.

'Our finding may be the start of a totally new biological control method,' Mr Tautz concluded.