Care sheet: Lasius niger

Caring for Lasius niger

Lasius niger, or the black garden ant, is a very easy species to keep. They are survivors and can handle harsh environments and situations. Each colony has got a single queen and can grow into tens of thousands of workers.

What does Lasius niger need?


Small colonies are best kept in test tubes with access to some sort of foraging area. Larger colonies can be housed in ytong nests (bonus: since the ytong is white, the ants will be easy to spot!) or in a dirt setup for them to dig through. Or why not try or own nest – AntKeep?


Sugar- or/and honey water. Fruits such as apples and pears are for most part popular. Experiment with different sorts of sugar mixtures to find out what your colony likes the best. The queen and larvae need protein. Provide this in the form of insects (fruit flies, mealworms, crickets, bees, wasps, beetles etc.) meat (free of poison or spices), eggs or something else containing protein. Be aware of what you feed your ants. Avoid poisonous things, such as the peel of sprayed fruit. If you’re catching your own insects, remember there is a risk they are infected with disease or parasites. So be careful and boil your insects before feeding them to your ants.

If you want to feed your ants live food, make sure the food is immobilised before feeding. Unless you have a huge colony your ants will probably suffer casualties while trying to kill their prey.


Temperature in the nest: 20-27°C. Does well in room temperature. Since Lasius niger, like most ants, enjoy heat a heat lamp or heat mat might be a good idea. But be careful not to burn your ants to death. Somewhere around 25°C a couple of hours a day maybe?

Tip! Only heat one part of your setup. This way the ants can choose themselves if they want to take part or not.


Lasius niger hibernates. This means they are used to not being active during the winter months. They go into their nest and huddles together, waiting for spring to come. To remain healthy, Lasius niger requires proper hibernation. The ants do not need to be fed during this time.

You can easily hibernate your ants in most spaces with temperatures below 5-10°C. Some even use their refrigerator to hibernate their ants. Just be careful exposing your ants to too cold temperatures.

The hibernation should be synced with the seasons. When ants usually withdraw from the surface in nature you should probably hibernate your colony.

The months of hibernation usually stretches from October to around March.


Moisture level: 10-50%. The species don’t have that extreme demands when it comes to humidity. But they don’t want it too dry (they will die!). Moisture is easily achieved by a simple spray with a garden spray bottle. Experiment with what the ants thinks is a good level of humidity. They don’t want i wet, but not dry either.

If you find your formicarium going dry too quickly you may have a material problem. Make sure your setup has enough things to bind the moist (dirt/sand etc.). Try putting a piece of wood in there or something to achieve the right conditions.


how to get rid of antsA small Lasius niger colony in a ytong nest. Photo: Lennart Tange

More information about Lasius niger


Worker: Length: 2,0-5,0 millimeters. Dark brown/black with greyish tones. The thorax is lighter than the rest of the body

Queen: Length: 7,0-10,0 millimeters. Brown shaded black color. Wings are transparent but ridden after the nuptial flights.

Male: Length: 3,5-5,0 millimeters. Brown shaded black color. Wings are transparent. (1)


Lasius niger is found throughout Europe and parts of North America and Asia (2). It is the Lasius species that settles furthest north, all the way to the northern parts of Finland. It has been found from California to Japan, and from North Africa to Finland.

Number of queens

Monogyne. Colonies only have one queen.


Nests in dirt/sand and prefer to situate themselves under stones or other objects that generates heat. The species is also found in tussocks, directly in the ground, lawns, pavements or close to plants.

Getting hold of a queen

In Europe and Asia, single queens with or without workers are often found in ant shops. Instead of buying a queen, since it is illegal in some areas, you can catch one yourself. Since Lasius niger likes nesting under stones it is a good idea to gently flip rocks to see if there is a queen in sight for you to capture.
Tip! The black garden ant likes heat. So, during warm days when the sun is up: try flipping stones to find the queen enjoying the warm upper floors of the nest!

Nuptial Flights

The nuptial flights take place somewhere between June and September. The European ants of the species tend to mate during hot summer days in July and August, while their North American siblings prefers the autumn months. It is not uncommon for people to see thousands of black garden ants flying away to mate with each other.


Lasius niger is a very aggressive and active species. But their weak mandibles seldom hurt our skin, so we consider them nice anyways.


1. Per Douwes, Johan Abenius, Björn Cederberg, Urban Wahlstedt (2012) Nationalnyckeln “Steklar: Myror-getingar. Hymenoptera: Formicidae-Vespidae” p. 151 (Swedish)

2. John H. Klotz, Urban Ants of North America and Europe: Identification, Biology, and Management p. 39

Further reading

Ant Care Sheet Lasius niger – AntKit

Lasius niger Care Sheet – ANTfinity

Black garden ant – Wikipedia

Lasius niger – AntWiki