Day 88: In finding new homes, we could take lessons from ants
Credit: Elva Robinson.
Often when moving to a new town, I’ll check out a lot of apartments before I find the right one. Other times I see a decent place and I just stop looking, even if there were more on my list.
That’s how ants do it, too.
Elva Robinson, a biologist at the University of Bristol in England, and her colleagues fitted rock ants with tiny radio-frequency identification tags (at left), each measuring one two-thousandth the size of a postage stamp, then watched as they chose between a poor nest nearby and a good nest farther away.
They saw something smart: when a colony of rock ants is in the market for a new home, scouts that find a good nest return home toΒ recruit their nest-mates. When the number of ants in the new nest reaches a quorum, the scouts quickly transport the rest of the colony by carrying nest-mates and brood.
There’s not a lot of waffling, either; very few ants appeared to make direct comparisons between the two nests before choosing.
“Each ant appears to have its own ‘threshold of acceptability’ against which to judge a nest individually. Ants finding the poor nest were likely to switch and find the good nest, whereas ants finding the good nest were more likely to stay committed to that nest,” Robinson said. “Individual ants did not need to comparatively evaluate both nests in order for the entire colony to make the correct decision.”
In fact,Β animals – including humans – that use comparative evaluation often make ‘irrational’ decisions, due to the context in which options are compared or by inconsistently ranking pairs of options, she said. For example: option A preferred to B, B preferred to C but C preferred to A.
“The ants’ threshold rule makes an absolute assessment of nest quality that is not subject to these risks,” Robinson said, pointing out that the result is usually better for the colony as a whole.
Source: Eurekalert press release. The research appeared Tuesday inΒ Proceedings of the Royal Society B.