Double effect

 
Published: Tuesday 30 September 1997

researchers in France have found that plants that had been genetically engineered to ward off destructive insects could also harm beneficial ones such as bees, shortening their lives and impairing their ability to recognise flower smell. Minh-Ha Pham-Delgue of the Laboratory of Comparative Invertebrate Neurobiology in Bures-sur Yvette, France who investigated the effects of engineered rapeseed on pollinating insects found that it contained genes, found naturally in some plants, that produce protease inhibitors -- proteins that interfere with enzymes in the intestinal tracts of insects. To find out how bees might be affected by high levels of protease inhibitors in stored nectar, the researchers exposed captive bees to sugar solutions containing up to 100 times the concentration of proteins found in the tissues of the engineered rapeseed. Bees fed on this solution for three months died up to 15 days earlier than those fed on normal sugar. After 15 days, the bees had trouble learning to distinguish between the smell of flowers.

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