As People Flee Detroit, Bumblebees Move In

Detroit Michigan has seen better days. Industrial manufacturing and auto jobs have been leaving the city in droves over the past ten years. What has replaced them is swarms of bumblebees. 

As cities and paved environments take over their habitats and suburban pesticide use increases, bumblebee populations are in trouble nationwide. In Detroit, the trend towards people leaving the city because of economic downturn has produced a perfect habitat for bumblebees. As a result, Detroit is one of the few urban places in America where bumblebee populations are growing. 

"Where we build cities or cultivate industrial farms," says researcher Paul Glaum at the University of Michigan, "we remove potential nesting sites--especially for species that build their nests in the ground, like most bumblebees do."

The decay of Detroit is good news for bumblebees even if it does nothing for the economic conditions of the city. It's not like they can pay taxes or improve the schools. Detroit is dying, but inside the city's borders, bees are thriving.

Baum and his colleagues collected 520 bees across 10 species. Most were collected from urban gardens, urban farms and a few nature preserves and rural farms using traps and nets. Researchers returned to sites every spring and fall to collect more bees and look for relationships between the number and variety of bees at each site and features of that location. It was during this analysis that the researchers recognized that Detroit stood out -- way out.

In most of the locations, more urbanization meant a decline in bee population. In Detroit, the trend was reversed. Vacant lots in Detroit are the norm. It was these vacant lots that improved the population of bees. More vacant lots means more unkept lawns and less pesticides. This produced more variety of flowers for bees to pollinate and less pesticides for them to endure. More vacant lots also means more areas for bees to make their homes. 

Now, if we could only get the bees to make hives for humans, we could be on to something.