How ants play the real estate market
Rock ants budget their resources toward finding a housing upgrade depending on how good or bad their current housing is.
The more a Manhattanite dislikes her apartment, the more time she’ll put into searching for a new one.Skip to next paragraph
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A rock ant does the same thing – and with the noisy input of hundreds of brethren, no less.
A new paper published in the journal Biology Letters reports that rock ants budget their resources toward finding a housing upgrade depending on how good or bad their current housing is. The research highlights the complex calculations that rock ant colonies are capable of making – calculations that stun scientists and casual observers alike, since these tiny insects do it all without a leader.
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Rock ants, or, Temnothorax albipennis, belong to the Temnothroax genus that includes some 346 species. Since their colonies are small, at just 50 to 600 individuals, these European ants have been convenient, popular research subjects, along with a few of their North American cousin species, like the so-called acorn ant.
Orange-brown colored, with a glassy-looking rear like an amber bobble, rock ants are small at just two to three millimeters. Somewhat counter-intuitively, these bantam beings don’t live “blink of an eye” lives, but boast lifespans up to several years long. A colony’s queen, a colossal and winged ant, can live up to a decade.
Rock ants, of course, will find a new home if their present one is destroyed – in the event of, say, a small child testing his or her dominion over everything smaller that he or she. But ants are not so complacent that they’ll bed down in just anything, so long as it’s not on the bottom of a shoe.
No, these ants prefer to climb the property ladder.
“Rock ants will always emigrate once their current nest is no longer considered hospitable,” says Carolina Doran, a PhD student at the University of Bristol's School of Biological Sciences and the lead author on the paper.
“Interestingly they also emigrate if they find a new nest that is sufficiently better then the one they are currently in,” she said.
And, like Manhattanites culling listings for apartments with elevators, laundry rooms, and – hey, why not? – splashes of exposed brick, ants are fussy property buyers. Ants prefer dark nests to bright ones. They like entrances small enough that intruders will have a tough time intruding. They want to know the square footage and how high the ceilings are.
“Ants know exactly what they like,” says Ms. Doran.
But unlike a Manhattanite eschewing plum listings in outer Queens for teaspoon-sized studios in the East Village, rock ants are prepared to travel far to find this prime real estate. In a 2009, a team of researchers also from Bristol’s Ant Lab traced ants’ whereabouts during a house hunt and found that the tagged ants would choose the best house even if it was nine times further from their current home than was a less swanky spot.
Still, finding a new place and moving is a lot of work, for ants and New Yorkers alike. So, how do ants budget their resources toward plying the real estate market? Under what circumstances are ants more likely to invest time and energy into culling the local area for better digs?
In September 2011, the new paper's authors, a team from the Ant Lab at Bristol, collected 15 ant colonies from Dorset, UK. The colonies were each monitored in five different artificial nests ranked in quality on a scale of one to five. They were also allowed to roam in an enclosed area outside each nest.
The researchers wanted to know how many ants the colonies sent outside the nest at each of the five locations. In the experiment, this number was an indicator of how much each of the colonies was budgeting toward finding a new place: the more ants outside the nest, the more urgent the colony’s search for superior digs.
The results were as predicted: when the nest was to the ants’ liking, the colony sent out fewer bantam real estate agents to comb the area for a better investment, the researchers found.
“It’s a satisfying result,” said Stephen Pratt, a researcher at Arizona State University who was not involved in the research. The findings are in keeping with his previous work showing that a cousin of the rock ant will allocate more house hunters when their circumstances are extremely bad versus just alright, he said. This new paper suggests that ants also make these calculations when faced with just subtle differences between home qualities, he said.