New Yorkers—or any urban dwellers, for that matter—are used to sharing the streets with a medley of animals, including rats, pigeons and squirrels. Although we often see those creatures as pests, it's our own habits that allow them to thrive: plenty of free food, in the form of litter and garbage.
As the New York Times reports, however, those vertebrate species aren't the only urban garbage disposals. A massive legion of insects also cleans up after us. And we're not just talking cockroaches, either. Dozens of species ranging from ants to mites to flies are busy chomping away at our refuse. Some work directly on the banana peels and sandwich scraps we leave sitting around, others on the leaf litter that we rake up in tidy medians.
Altogether, though, on Manhattan alone insects eat the equivalent of 60,000 hot dogs per year, the Times writes, or up to 2,100 pounds of dry weight organic matter.
Researchers arrived at this calculation after sampling parks and medians in Manhattan for insects; they collected around 16,000. They also laid food traps—some that excluded larger animals like rats, others that were open to the elements, the Times says—and containing treats ranging from chips to cookies. Insects ate all of their food, but the offerings that were also available for vertebrates disappeared about twice as quickly, indicating that insects and vertebrates compete for the same types of food resources in the city.
So while the thought of insects crawling all around us might be a bit rattling, the Times points out that their function in the city is actually helpful: they likely limit the number of rats and are happy to pick up after us.