Common fruit flies in Australia developing resistance to insecticides

New research has found that fruit flies in temperate parts of Australia are becoming resistant to common insecticides. The study, led by the University of Melbourne, found fruit flies living in the south eastern part of the country -including Victoria, New South Wales and parts of South Australia- were evolving resistance to the effects of common sprays.

It found fruit flies living in temperate areas were also better at resisting insecticides than those living in more tropical areas.

The study focused on the fruit fly’s resistance to imidacloprid-stronger evidence of positive selection in temperate populations compared to tropical populations’’.

Lead researcher Alexandre Fournier-Level said the fruit fly was evolving despite ‘multiple stresses’. “That is not only insecticides or temperature or humidity, they have to cope with all the stresses all at once,’’ he said. “It is a game between a bait and a target. So, an insecticide being the bait and its molecular target being generally located in the fly’s brain. The first and most common mechanism is that the target changes its shape and the insecticide can no longer reach the target.’’

Dr Fournier-Level said agribusinesses across the world needed to instead look at genetic and ecological factors to manage the pest: “What is definitely over is this era which started in the 1940s where we could just use one barrel of chemical product to actually deal with any and every species.”

He said if we know tropical fruit flies do not evolve to resist insecticides, we could use them to help breed out the insecticide resistance in temperate flies. “Therefore, we could diminish the level of resistance in the population. Once we figure out what is the actual molecular mechanism at the gene level that confers one thing over the other, play one against the other.’’