It looks like people aren't the only ones hooked on junk food.
Researchers from the North Carolina State University have discovered that certain ant species living on the streets of Manhattan have developed an affinity for human food, offering hints into how some ant species are able to thrive in urban settings.
Clint Penick, a postdoctoral researcher from NC State and lead author of the paper published in the Proceedings of the Royal Society B, explained that he and his colleagues were interested in learning why some ant species live alongside people, while others prefer less urban environments. Their findings could help determine which ant species contribute the most to cleaning up trash.
Over 100 ant samples were collected by researchers on sidewalks, parks and street medians in Manhattan. The samples, representing 21 different species, were then examined to detect isotope levels in their bodies.
Animals – including people – absorb the carbon present in their food. Carbon-13 is associated with plants like sugar cane and corn. As refined sugar and corn are present in almost everything people consume, carbon-13 is also found in everything that consumes human food — including ants.
The researchers discovered that the pavement ant – the most common ant species on medians and sidewalks – has the highest level of carbon-13. Overall, the carbon was detected in all ant species living close to humans, while ants in parks had the lowest levels.
"Human foods clearly make up a significant portion of the diet in urban species," said Penick, adding that a preference for this type of food helps explain how pavement ants have grown their population in cities to a massive degree.
But while most urban ant species are hooked on human food, there is an exception: the Lasius cf. Emarginatus. This ant species only began to appear on the streets of Manhattan in the last five years, and though it is comparable in number to pavement ants, it does not like human food. Instead, the ant species would rather forage on trees growing along the streets.
Penick said this shows how complex urban ecosystems are, and that there is much more to learn about how species relate with each other and their environment.
The study received funding support from the Southeast Climate Science Center at the U.S. Department of Interior and the National Science Foundation. Amy Savage, also a postdoctoral researcher from NC State, and Rob Dunn, a biological sciences associate professor from the university, also contributed to the study.
Photo: Steve Snodgrass | Flickr
