We, humans, sleep between 6 and 9 hours a night on average. So obviously, with a little curiosity, we quickly wonder how and when the other living beings around us sleep.
The sleep process: why and how?
Sleep is a process necessary for the proper functioning of the brain: it allows it to set up certain neurological processes that serve to eliminate kinds of waste that would accelerate cellular aging if they were not eliminated. Sleep is, therefore, necessary for all living beings with a brain, but everyone does not sleep in the same way. For example, the dolphin, which has, like us, two hemispheres, has the ability to put one hemisphere into sleep at a time: only one half of its brain sleeps while the other remains active to prevent it from sleeping. to drown.
And yes! Like us, and like dolphins, ants have a brain, made up of around 100,000 neurons, or nearly 4% of their total weight (compared to 2% for a human being), so they need rest.
However, we perceive activity in the anthill both day and night, why? Quite simply because the colony needs its workers to be constantly active: the colony is a vulnerable entity, with many predators, if the whole nest fell asleep at the same time, no one could defend the nest against an attack. So there is a specific rhythm for the workers to rest. Unlike humans, there isn’t a social schedule where everyone goes to bed.
According to the researchers, there are two main modes of rest within the anthill. The queen rests continuously for about 9h, so her resting process is very close to ours. The workers have a sleep process quite different: they perform short naps regularly. Their total rest time in a day is close to that of the queen, but it is divided into full phases of sleep. Thus the social organization specific to ants continues harmoniously.
During the winter, a large number of species go into diapause: they reduce the colony’s activities, feed less and the queen produces little new brood. It is also a process of rest, but not of sleep: the colony preserves its resources to avoid the exhaustion of the queen and the workers in a period when food is scarce.
Researchers recently discovered that in addition to resting, some ants were not active in daily colony missions. Yet these ants were not old, nor in poor health. During an 18-day observation, these ants had performed no activity in the anthill. So why? Scientists are currently questioning this subject: would they have a particular role? Would they be reserved for a particular unforeseen task, such as defending during an attack? This is enough to arouse the curiosity of researchers and myrmecophile amateurs!
Small points on the sources
This article, like many articles on this blog, is inspired by our reading of Luc Passera, a recognized myrmecologist with a developed pedagogical sense. We encourage you to discover his works which are full of information around the little world of ants.