Adventures Lazy ants do to make themselves useful

Images of ants are always presented as diligent in human mind but a new research might come as a surprise to many.

Biologists from University of Arizona reported that the large no. of "workers" that make up an ant colony spent the vast majority of their day engaging in one task: doing absolutely nothing.

Daniel Charbonneau, who studied the behavior of these lazy ants, said, "They really just sit there."

"And whenever they're doing anything other than doing nothing, they do chores around the nest, like a bit of brood care here or grooming another worker there."

Charbonneau found that around 40 percent of individuals are most likely to be an inactive, with some variation between seasons, colonies and species.

Ants that belong to the species Temnothorax rugatulus, don't appear to be freaks of nature. Charbonneau and his doctoral adviser, Ecology and Evolutionary Biology Professor Anna Dornhaus, published those results in 2015. The researchers could only speculate over the purpose of keeping eye on crowd of inactive "workers."

In the open-access journal PLOS ONE, authors Charbonneau and Dornhaus shows that inactive ants may act as a reserve labor. When researcher removed the 20 percent of most active workers, they found that within a week, they were replaced mostly by individuals belonging to the "lazy" demographic, which stepped up and increased their activity levels to match those of the lost workers.

Charbonneau said, "This suggests that the colony responds to the loss of highly active workers by replacing them with inactive ones."

Researchers tracked their movements through video recordings and while analyzing the video recordings they observed that a colony breaks down into four main demographics: lazy ants; so-called walkers that spend their most of time just wandering around the nest; foragers that take care of outside tasks such as foraging and building protective walls from tiny rocks; and nurses in charge of rearing the brood.

Charbonneau observed that the lazy ants tend to have more distended abdomens, hinting at the possibility that they could serve as "living pantries."

Charbonneau said, "My speculation is this: Since young workers start out as the most vulnerable members of the colony, it makes sense for them to lay low and be inactive." "And because their ovaries are the most active, they produce eggs, and while they're doing that, they might as well store food. When the colony loses workers, it makes sense to replace them with those ants that are not already busy pursuing other tasks.