Yes, ants do sleep but they do so in a manner that’s very much different from humans. Ants are polyphasic, and so instead of having one elongated period of rest, they take multiple short naps throughout the day.
In this article we’ll detail what happens when ants sleep as well as how long, when, and lastly, where they sleep.
What Happens During Ant Sleep?
These periods of rest are characterized by a decrease in overall activity. Mandible and antennae activity decrease by up to 65% and ants may become unresponsive to contact. They may also exhibit rapid antennal movement (RAM) which may be likened to REM sleep in vertebrates, suggesting that they too may also enter deep sleep.
In queen ants, sleep episodes take two forms: deep sleep and dozing. In deep sleep, the queen’s antennae and mandibles are retracted and they become unresponsive to contact.
On the other hand, when dozing, the queen’s antennae are partially extended and their mandibles are partially open such that the tips of the teeth are touching. In this state, the queen is most likely to respond to contact by other ants with antennal movement.
How Long Do Ants Sleep?
A study published in the Journal of Insect Behavior showed that fire ant workers slept an average of 253 sleep episodes lasting 1 minute each, totaling to around 4.8 hours of sleep daily.
Their queens, on the other hand, averaged a lower number of 92 sleep episodes per day but had longer episodes lasting around 6 minutes each. This totals to around 9.4 hours of sleep daily, almost two times that of the workers.
These differences in total sleep duration and time of sleep intervals reflect the ant colony’s social hierarchy.
For instance, workers have to sleep in shorter intervals because they have to remain vigilant and active. Keep in mind that these workers do most of the work to keep the colony going. They look for food with which they feed the queen and her brood and to add to that, they also maintain the nests as they keep it clean and defend it from intruders.
Such is also why worker ants have arrhythmic or irregular sleep episodes. At any given point in time, a significant portion of the worker caste is alert and awake to complete the tasks in need of attention.
Meanwhile, queens have the luxury of taking longer rest periods, as they don’t need to participate in time consuming tasks. They simply need to focus on reproducing as worker ants take care of everything else, including the queens themselves.
As far as the time of overall sleep goes, the fact that queens sleep almost twice as long as workers highlights the emphasis on queen longevity. A study on Drosophila flies suggests that insects that have more sleep tend to live longer. So while sleep may not exactly be the sole reason for the queen’s longevity, it may perhaps be a factor in why they live way longer than other ant castes. After all, they are the most well rested caste in the colony.
When Do Ants Sleep?
The sleep and activity cycle of many animals is based on the circadian rhythm. For example, we humans generally follow a light-related circadian rhythm as we sleep at night and stay active during the day. Ants however, particularly the workers, don’t typically exhibit a defined circadian rhythm and instead sleep in irregular patterns.
The same study on fire ants showed that unlike us humans, worker ants aren’t sensitive to dark or light photoperiods. Worker ants were shown to work regardless of time meaning their active-rest rhythms don’t depend on whether it’s night or day. Instead, their active-rest rhythms were more dependent on the tasks at hand and the social interactions within the colony.
For example, a study on the monomorphic ant Diacamma sp. showed that ants tending to eggs or larvae exhibited around-the-clock activity with no apparent rhythm. However, they do start showing an active-rest rhythm when they’re paired with pupa which require little care or when they’re isolated from the colony.
This suggests that worker ants may inherently have circadian rhythms but are greatly affected by social interactions within the colony that induce the loss of these active-rest rhythms.
Being that ants don’t tend to be isolated from their colonies, worker ants therefore typically have arrhythmic sleep cycles. They sleep whenever they can afford to, and so at any given time, there will be a number of individual ants taking a break and sleeping.
In contrast, queen ants tend to maintain a more regular schedule. The same study on the polygynous fire ants revealed that queens slept piled on top of each other and all at the same time. What determines when they fall into this cozy slumber though wasn’t defined.
Where Do Ants Sleep?
Since ants sleep in very short intervals, they really don’t need to have a bedroom. Such is why despite their nests typically having a variety of chambers for different purposes, they don’t have designated ones for sleeping. If they intend to doze off, they simply stop in place and take a break. This is supported by how ants in a laboratory setting were shown to sleep pretty much anywhere in their artificial nests.
Are Ants Active At Night?
There are ants that are active at night while there are those that prefer to work under daylight. Also, as previously mentioned, some ants work round the clock and don’t consider these light or dark conditions at all.
Do Ants Hibernate?
Ants don’t technically “hibernate” but they do enter a similar state called diapause and become dormant for a duration of around three to four months. This adaptive state allows them to bypass extreme conditions like the winter cold with minimal food and energy expenditure.
Summary: Do Ants Sleep?
Yes, ants sleep. As polyphasic animals they sleep for two or more episodes daily. In fact, research has found that worker ants take hundreds of minute long naps throughout the day while queens have less frequent but significantly longer nap times.