Studies have shown that people who use excessive insecticides may suffer more cancer. But now researchers at North Carolina State University have found another reason to go easy on the pesticides.
According to this study, insects in a city like New York are essential for disposing of garbage. They also help control the spread of rats. Broadway, often known as the Great White Way, wouldn’t be so white without its resident arthropods (a classification that includes both insects and spiders).
“We calculate that the arthropods on medians down the Broadway/West St. corridor alone could consume more than 2,100 pounds of discarded junk food, the equivalent of 60,000 hot dogs, every year — assuming they take a break in the winter,” says researcher Elsa Youngsteadt. “This isn’t just a silly fact. This highlights a very real service that these arthropods provide. They effectively dispose of our trash for us.”
The scientists were busy studying insects living in New York, when Hurricane Sandy flooded New York in 2012. Consequently, they altered their research to include observations about whether Sandy had influenced the insects’ behavior.
To calculate what the arthropods were eating, the scientists dished out potato chips, cookies and hot dogs in parks and on the medians of busy streets. The samples included two collections of food at each selected site. One sample was in a protective cage so only arthropods could consume it. The other sample was on the ground, available for any stray animal.
The researchers discovered that arthropods on the medians consumed up to three times more junk food than they did in the parks.
The primary arthropod consumer: ants.
“We think this is because one of the most common species in the medians was the pavement ant (Tetramorium species), which is a particularly efficient forager in urban environments,” Youngsteadt says.
They also found that rats and pigeons were big customers for junk food.
“This means that ants and rats are competing to eat human garbage, and whatever the ants eat isn’t available for the rats,” Youngsteadt says. “The ants aren’t just helping to clean up our cities, but to limit populations of rats and other pests.”