The Colorado potato beetle has developed resistance to over 50 different types of insecticides. This makes the insect a "super pest" causing damage to potatoes all over the world.
As Eric Hamilton writes in an article for the University of Wisconsin-Madison website, new research shows that the beetle is so resilient largely due to diversity in its genome.
The genetic diversity of the pest population and the arsenal of existing resistance genes are likely to give the beetle strong resistance in the future. But a new understanding of the pest's genomic resources could help scientists develop pest control systems.
Research team at the University of Wisconsin-Madison sequenced the genome of the Colorado potato beetle for the first time in 2018. Since then, they have been genome-searching to understand how an insect can develop resistance to new insecticides so quickly. To do this, they sequenced several dozen beetles from all over the United States. These regional populations differ in what pesticides they are resistant to and in origin.
The scientists found that these various regional groups evolved so rapidly because their parent populations already had the genetic resources needed to develop resistance to insecticides.
This rapid evolution, based on the richness of the existing genetic diversity, is in conflict with the older model of evolution, which assumed that rare mutations should occur slowly in a population. While new mutations are evolving and may contribute to insecticide resistance, the rapid response of the potato beetle to new chemicals in different parts of the country can only be explained by its existing diversity.
It is unlikely that even a completely new insecticide will keep the pest under control for long.