Ants don’t technically hibernate, but they do enter a hibernation-like state called diapause during the cold season. During this state, ants enter a period of rest where all activity and growth ceases as they simply run off stored energy.
In this article, we’ll look into how ants handle the winter months as we further discuss what diapause is, why ants do it, and how they prepare for it.
What Is Diapause?
By definition, diapause is the physiological state of dormancy or period of suspended development typically observed in arthropods like ants. It’s triggered by changes in the environment such as changes in daylight and temperature and is a means of surviving such extreme environmental conditions.
Again, this state is characterized by metabolic depression which leaves ants sluggish or even completely immobile. In some cases, ants remain capable, albeit slower than usual, of behaving the way they usually do, that is move freely, collect food, and feed themselves, although research has found some evidence of diapause causing ants becoming less disposed and aggressive about foraging.
On the other hand, some ants also fall into a state of complete stupor when overwintering and they cease all development and activities including feeding and reproduction.
How Long Do Ants Stay In Diapause?
Diapause typically lasts the entire cold season, so ants stay in the state for an average of three to four months. However, different ant species react differently with some ants able to get out of diapause earlier than others.
For instance, in Myrmica ants, diapause can easily be broken by exposure to long photoperiods, whereas Formica ants tend to require long periods of warm conditions to awaken.
In general though, ants should be out of diapause when spring comes and temperature gets warmer. It is then that they become active, start coming out of their nests, and start foraging again.
Why Do Ants Enter Diapause?
Temperature plays a significant role in how ants function and it directly affects their metabolism, growth, and development. Therefore, it’s important for ants to achieve ideal body temperature if they are to function properly.
However, as ectotherms or cold-blooded animals, their body temperatures are directly affected and changes in response to atmospheric temperature. So when it gets cold, their body temperatures also drop significantly and their movements inevitably slow down or cease due to slower metabolism. Meaning they don’t necessarily have much of a choice but to enter diapause during the cold season.
That said, diapause does provide them with an advantage. As previously hinted, diapause aids in survival as ants are able to pass through extreme conditions without expending too much energy and allows them to rest as they wait for ideal conditions.
How Do Ants Prepare For Diapause Or The Cold Season?
To prepare for the expected period of dormancy, most ant species eat large amounts of food during autumn to fatten and build up their energy stores. Doing so will allow them to get through and survive overwintering without having to eat.
They also start organizing their nests to optimize heating and prevent them from freezing to death. Underground ants for example, seal the entrances to their nests and burrow deeper into warmer ground. Other ants may also take refuge under rocks or tree barks which acts as a source of heat.
Do Ants Migrate?
Migration is quite rare in ants, but some ant species such as the Polyrhachis simplex, Tapinoma sessile, and Formica japonica, all showcase migratory behavior according to seasonal changes in temperature.
Where Do Ants Go In The Winter?
Even before winter starts, ants start finding warm areas which will help them survive the cold. Again, these includes deeper ground, and under tree barks or rocks which serve as heat collectors. In some cases, they may even take refuge in our homes and spend the winter hidden in our walls or underneath our floors.
Do All Ants Undergo Diapause?
Not all ants go into diapause. Most tropical ants for instance, have no developmental arrests and even some of those that live in temperate climates are yet to fully adapt true diapause. Instead, they enter a cold coma state suffering strong mortality.
Do Ants Die In Winter?
Some ants do in fact die during winter. As mentioned, some ant species are not capable of diapause and instead, simply enter a cold coma wherein chances of survival is lower. Research for example has shown that Pharaoh ants suffer great mortality in low temperatures to the point that colonies eventually die out in a month.
How Does Diapause Differ From Hibernation?
The primary difference between diapause and hibernation is the fact that diapause includes a temporary pause of growth and development. Other than that though, they are very much similar. Both are characterized by a metabolically depressed state and general inactivity which allows animals to withstand extreme or adverse environmental conditions.
In summary, ants do not technically “hibernate” during the cold season 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.
During this state, their activities, growth, and development stops as their metabolism slows due to the cold directly affecting their body temperatures. And so as preparation for this expected period of dormancy, they prepare during the autumn season by fattening up and preparing their nests for proper heating.