Monoculture growing fields attract a plethora of pests, while a plot rich in biodiversity repels them. But why? A new study offers answers.

To find out exactly how plants use variety to their advantage, biologists looked to the insects that pester them. Scientists surveyed the feeding preferences of 53 species of insects, and found each has very specific nutrient ranges at which they thrive.

When plants are too rich or too poor in nutrients, invading insects struggle. A plot rich in a variety of plants featuring a variety of nutrient levels increases the chance that an insect will flounder and not flourish.

"Farm fields can create monocultures where pests may find the perfect nutrition to be healthy and reproduce," lead researcher William Wetzel explained in a news release. "Planting fields with higher plant nutrient variability could contribute to sustainable pest control."

Wetzel is now an entomologist at Michigan State University but he conducted the research into plant diversity while studying at the University of California, Davis. His research was published this week in the journal Nature.

It's unlikely Wetzel is going to convince commercial farmers to pattern their fields after small family farms -- the crop yields offered by large monoculture farms are what help commercial farmers turn a profit. But Wetzel thinks there are ways to boost diversity without sacrificing production.

One way is planting a diverse array of genotypes of a single crop -- a strategy already being used among rice and wheat fields to minimize the spread of disease.

"So far people haven't done that in ways to reduce insects," Wetzel said. "But it shows that it's possible to mix varieties and genotypes together. Now we need to think about how to do that to control insects."