Next time you accidentally drop a piece of food on the ground, think of all the tiny bugs that are about to have a feast. A new study finds that arthropods, like millipedes, spiders and ants, chow down hard on junk food discarded in New York City. Along the Broadway/West St. corridor in Manhattan, they eat over 2,100 pounds of junk food each year. That’s the equivalent of 60,000 hot dogs.
The researchers, writing in the journal Global Change Biology, doled out hot dogs, cookies, and potato chips in NYC’s city parks and street medians. At each site, one set of food was put in a cage where only crawly arthropods could access them. The other set was open, so rats and pigeons could also eat them. Then, after a day, they looked to see how much food had been consumed.
The result: arthropods ate up to three times more food in medians than in parks, where there is more biodiversity and hence more arthropods to eat the food. Researchers suspect this is because the pavement ant, a savvy urban forager, tends to lurk in medians. City medians also tend to be hot, and heat speeds up the arthropod metabolism.
Overall, the arthropods ate 32% of the caged food. Animals, including arthropods, ate 80% of the non-caged food. In other words, insects and disease-carrying animals like rats compete for food when it’s out in the open. This is not all that surprising; arthropods are known to forage for small amounts of food in other environments. But this is one of the first studies to reveal their habits in cities, which will become bigger and house more of us in the coming decades.
“Despite their reduced diversity, urban ecosystems provide services, such as air purification and pollination, to city residents,” the researchers write.
It may not seem to matter whether a pigeon or an ant eats your cookies, but it does. The ants are curbing the population of larger pests, which can carry diseases, and are more disruptive in general. We should be rooting for the arthropods to thrive.