When we complained about having too much homework, our high-school science teacher told us about worker ants. “They keep their head down and work all day without making a fuss,” she said. “You should, too.”
Unfortunately, she was wrong. Most worker ants, according to a study in Behavioral Ecology and Sociobiology, don’t actually work most of the time. In fact, most of them are lazier than I was in school.
To come to this conclusion, Daniel Charbonneau and Anna Dornhaus of the University of Arizona observed five ant colonies in their lab. Over two weeks, a camera recorded five minutes of action six times a day.
Based on the how often ants repeated an activity, it was clear most ants specialized in what they did. They could be grouped as external workers (foragers, builders, etc.), nurses, patrollers, and lazy slackers (or, technically, inactive). The last group surprised Charbonneau and Dornhaus: Most ants took time to rest, but some ants were resting all the time.
Why so much laziness? One reason could have been that these social insects’ work is determined by their circadian rhythm, and so they work only at certain times of the day. But the researchers recorded the data at different times of the day, and at least in this group of ants, it doesn’t seem to be the case.
It could also be that they are just lazy in a lab. But studies in the wild agree with the results found in this study. Also, this phenomenon is not unique to ants. Previous studies have shown that more than 50% of wasps, termites, and even bees fall in the mostly inactive category.
Other reasons then, Charbonneau and Dornhaus speculate, could be: need for rest, delay between tasks, time for digestion, other side-effects of working, or a combination of all those. And it may be that those who don’t work at all are either too young or too old to do any work.
The results could change if, instead of being observed for short intervals, we were able to observe them for longer. But Tobias Pamminger, an evolutionary biologist at the University of Sussex, isn’t so sure.
“I can conclude after eight years of looking at ants that most of the ants are lazy most of the time,” he said. “A few ants do all the work.”
Although we are not yet sure why, it seems most worker ants evolved to be pretty lazy. Too bad I didn’t know this in school.