New Yorkers have always had a symbiotic relationship with rats on the subway tracks, pigeons swooping down from trees and rooftops, and squirrels dodging in and out of traffic. All in pursuit of the food we litter about our cities.
A study, which was published in the educational journal Global Change Biology found that millions of tiny insects are also picking up after us.
Researchers working in Manhattan’s parks and street medians set out to measure the population of ants, millipedes, mites, spiders, etc. They placed Ruffles potato chips, Nabisco Nilla Wafers and Oscar Mayer Extra Lean Franks in cages that allowed insects in but kept rats, squirrels and other vertebrates out. After 24 hours, they returned to see what had been consumed. By sucking the bugs into aspirators, they found over 16,000 arthropods, including 32 different species of ants.
100% of the food placed out for insects only, on a third of the street medians, was consumed. Twice that amount was eaten, where all animals had access to the same food. This suggests that vertebrates and insects can thrive on the same littered junk food diets.
The researchers attracted a lot of attention from passersby. While some New Yorkers thought studying their urban insects was really interesting, most just wanted to learn how to get rid of them and to tell their infestation stories to eager listeners.
Dr. Elsa Youngsteadt, a research associate at North Carolina State University and lead author of the study’s paper said, ” it highlights a very real service that these arthropods provide. They effectively dispose of our trash for us.” Urban ecology is not widely researched because its so much more favorable to study in a protected natural area. “But,” she added, “more than half the world’s population lives in cities. We have to decide how the organisms living around us provide us with services or disservices.”
The researchers estimate that in a single, block-long median strip, over a period of five to eight months, New York’s premier street cleaners – the arthropods – can consume over one ton of discarded junk food each year. That amount of food garbage looks like 60,000 hot dogs, 200,000 Nilla Wafers, or 600,000 Ruffles potato chips.
Levi Fishman, the city’s Department of Health and Mental Hygiene spokesperson, said, “This study confirms that street litter, particularly discarded food, is a major draw for rats and other pests. The public really needs to dispose of garbage in one of the many trash receptacles throughout the city.” Pests like pigeons, rats, and flies, harbor and spread human pathogens. And, cleaning up after sloppy eaters costs NYC over $11billion/year. For facts about litter click on https://www.ncdps.gov/Index2.cfm?a=000001,002895,002903
The study’s team thinks that future work should explore the conditions “favoring the competitive advantage of arthropods as food removers in cities.” Future urban habitat managers could create environments that favor ants over rats, benefitting the public’s health. We could make our city environments perform more constructive functions.
“You may not like ants,” Dr. Youngsteadt said, “but you probably like rats much less.”
I personally couldn’t agree more! This spring’s infestation of ants, in our kitchen, would not have been even remotely tolerable if all those scurrying little creatures were rats.