我们懒一些对蜜蜂有好处

This is Scientific American - 60-Second Science. I'm Jason Goldman. Add up every golf course, athletic field, industrial park, and yard in the U. S. and you have an area nearly the size of Florida.

Upon first glance, all that lawn might seem a biological wasteland-a monoculture of grass. But while natural areas in the U. S. continue to decrease thanks to urbanization,

urban green spaces-including lawns-could become more important reservoirs of biodiversity. What happens if we mow our lawns less? Do we get more lawn flowers?

And if we get more lawn flowers, can we get more bees? U. S. Forest Service ecologist Susannah B. Lerman.

She and her colleagues devised an experiment to see if front lawns could in theory provide decent habitat for bees – and if so, how to do it. So they recruited 16 homeowners from a Massachusetts suburb and monitored for flowers and bees throughout the summer for two years.

Each of the homeowners agreed not to use any kind of pesticide or herbicide. And none had cultivated any sort of pollinator or vegetable garden that could skew the results.

Some of the lawns were mowed weekly, some every other week, and others were mowed every three weeks. When we mowed the lawns less, we got more flowers, roughly two and a half times more.

But it was those that we mowed every two weeks that had the most bees. No surprise, flowers were most abundant on the lawns mowed least often.

But why do bees like a bit more frequent mowing? Lerman thinks that's because most of the bees she found were tiny native sweat bees, roughly the size of a grain of rice.

Critters that small could find it difficult to navigate through the taller grasses. In all the researchers found 111 types of bees over the course of the study.