A new study presented by North Carolina State University has concluded that ants and other arthropods provide a vital service in the disposal of garbage in New York City. These minuscule, almost invisible scavengers go about their business 24/7 with a relentless, unceasing zeal. Unnoticed underfoot, they consume unbelievable amounts of edible detritus.
New York City alone produces an estimated 3 million tons of garbage per annum. In major metropolises, individual residents generate about 23 pounds of refuse per year. Food waste alone amounts to about six pounds per city dweller.
Dr. Elsa Youngsteadt, a research associate at the university, is the lead author on the study Habitat and species identity, not diversity, predict the extent of refuse consumption by urban arthropods. This was published in Global Change Biology.
The team sampled arthropods – ants, beetles, mites, insects and millipedes – in street medians and parks in Manhattan to measure biodiversity. They aimed to observe the garbage consumed, and whether it was greater in specific locations. A prime objective was to check if more trash would be disposed off in areas of more diversity.
They placed specially constructed, rodent-proofed cages that only ants could access on the medians along West Street, Broadway and 11th and 12th Avenues on Manhattan’s west side. Similar contraptions were installed at 21 locations in the city’s parks. These were packed with vast amounts of junk food – hot dogs, chips and cookies.
The same process was repeated outside the cages as a control to compare how much was being consumed by the city’s other refuse-eaters. Twenty-four hours later they returned to find 85 percent of the food within and without the cages gone.
They estimate the bugs on the medians ate an average of 3 or 4 grams per day, two to three times more than those in the parks. This consumption rate amounts to an astonishing 2100 pounds of food per year, even discounting the winter months.
This totals to 60,000 hot dogs, 200,000 wafers or 600,000 potato chips. If expanded to other areas, the amount of garbage disposal by ants in NYC would amount to staggering numbers.
Aaron Ellison is a senior research fellow in Ecology at Harvard Forest and lead author of A Field Guide to the Ants of New England. He said the study reveals that insects and other organisms both indigenous and foreign are capable of adapting to and evolving in largely human habitats.
There are 42 species of ants in Manhattan. The grassy medians are home to 18. The most common – the pavement ants – Tetramorium sp. E – whose colonies can number 10,000 are the most efficient foragers.
Ants compete with disease-carrying rats, mice, pigeons and other rodents for nourishment, disposing of huge amounts before they can get to them. They are hunters that help to keep cities clean and discourage populations of other pests.
Hurricane Sandy interrupted the research in Dec. 2012. In spring of 2013, it was expanded to examine whether flooding had affected the behavior of insect populations. The findings concluded that the hurricane had no measurable footprint on the food habits of arthropod populations in New York. This was despite many of the study sites having been flooded with salt water. These minute life forms can survive and function even in the face of disaster. This is encouraging news for urban ecosystems.
Ants, the tiniest garbage disposal units in NYC are the unsung heroes that vastly impact the environment in keeping it free of edible litter. Their role in ridding metropolises of vast amounts of refuse seems to support the famed biologist E.O. Wilson’s maxim that “ants are the little things that run the world.”
By Bina Joseph
Photo by Taro Taylor – Flickr License
Photo by Asobi Tsuchiya – Flickr License