Butterflies and biopesticides

1997/07/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Zoologia
• Ingurumena

Although the biopesticides currently used are good, resistance to them can be developed faster than farmers expect. A study of the butterflies Plutella xylostella explains that resistance can spread in a few years, unless these butterflies are in contact with toxins produced by the bacteria Bacillus thuringiensis. The different types of this bacterium produce hundreds of Bt toxins, but only some are useful to combat pests.

Therefore, scientists work hard to find a genetic response to each toxin. Researchers from the US and Canada have analyzed two types of butterflies. One of them was heavily affected by Bt toxins and the other was not affected in the last 100 generations.

After a series of crossover experiments, researchers conclude that butterfly puppies that have survived a toxin will also survive with four toxins. According to the researchers, the resistant gene is 21% of butterflies (much higher than biologists expected).