More and more tenants and homeowners are looking for help because ants are suddenly swarming around the building. But it is not always a problem. Occasionally the insects stray into strange habitats. Species identification is necessary so that possible dangers can be identified and solutions can be addressed.
Determine species occurring in the house
It is extremely important that you identify the ant species before taking control measures. This will give you important information about the lifestyle of the different types of ants. You can more easily assess whether the insects are really living in walls, basement rooms and niches or whether they have just found their way into the house. Not all ants prefer to be close to humans.
| Genus | Size | Special features | |
|---|---|---|---|
| Path ants | Lasius | little ants | make hardly any demands on the living space |
| Forest ants | Formica | approx. 10 mm long | Omnivores, usually build nests in the ground |
| Carpenter or giant ants | Camponotus | large ants, up to 18 mm long | colonize moist timber |
| Garden or knot ants | Myrmica | medium-sized ants, approx. 5 mm | build underground nests or colonize dead wood |
Brown ants
The red garden ant is very common here
The red garden ant has a reddish brown color and is one of the most widespread species in Central Europe. It inhabits a wide variety of habitats and can be found in meadows, gardens, forests and bushland. Here it nests in dead wood, under moss cushions and stones or in open fields and feeds on honeydew. Other brown colored species are often considered as ants in the house.
Brown garden ant (Lasius brunneus)
This species goes by many names and is also known as the brown carpenter ant. It is strikingly two-tone and has different shades of brown. While the head and abdomen are dark brown, the trunk, stalks and extremities appear brownish-gray or yellowish brown and sometimes slightly reddish.
Danger of confusion:
- Red garden ant (Myrmica rubra)
- Bicolored garden ant or red-backed house ant (Lasius emarginatus)
The species is tied to woody plants. It inhabits rotten dead wood in open forests, old trees in orchards and in gardens or parks. Here it feeds on the honeydew of aphids. Stored or built-up wood that is located near deciduous trees is also often colonized. The ants find optimal living conditions in moist lumber, plasterboard and thermal insulation boards. Therefore, Lasius brunneus is the most frequently reported pest ant in Germany.
Black Ants
This group includes species from different genera whose identification presents greater difficulties. Therefore, not only the color but also the habitat should be examined more closely. The demands on the environmental conditions vary considerably depending on the species.
Black garden ant (Lasius niger)
The black ant is rarely found in living spaces
The species is not a typical house ant. It builds its nests in moderately dry habitats and prefers cavities under stones and in the grass to raise its warmth-requiring brood. When the weather becomes suboptimal, it looks for sheltered areas and can appear in cracks in walls. They can enter homes through insulation material if there is a direct connection between the insulation layer and the nest. Reports of nests under tin roof structures are rare.
Typical for the species is dense body hair, which shines silvery to varying degrees depending on the light. Fighting the dark brown to black ants is usually pointless. After a colony has been exterminated, the next colony settles in the favorable nesting areas of its predecessors.
Black carpenter ant (Camponotus herculeanus)
This black colored species has dark red legs and scales. Her body appears stocky because of her short extremities. The ant prefers shady and moist soils in forests. It is often found in spruce forests in mountainous areas, but can also be observed in open areas and lowlands. The insects colonize wood through external damage or via the roots.
This is where the ant builds its nests:
- mainly in the wood of he althy trees
- preferably spruce, occasionally pine, rarely hardwood
- Nests partially extend into the ground
- only colonizes built-up wood with direct contact with the earth
Glossy Black Carpenter Ant (Lasius fuliginosus)
The shiny black carpenter ant sometimes gnaws on a roof beam
This species is characterized by a deep black body, the color of which shines conspicuously in the light. Mouthparts and antennae are brownish in color. The carpenter ant prefers to build its nests in dead wood. It also settles in fence posts or roof beams of buildings, although modern houses are rarely damaged by this species.
The workers build a so-called cardboard nest in the wood, which consists of chewed wood, sugar and other solids. This creates a blackish mass, which is filled into the cavities that have been gnawed. The cardboard nest forms the growth basis for the fungus Cladosporium myrmecophilum. Its fine network of roots penetrates the thin walls and in this way strengthens the nest.
Yellow ants
Yellow meadow ants mostly live in the soil
Brightly colored ants such as yellow meadow ant or yellow thief ant live underground in the substrate of various landscapes. While the former species feeds on the honeydew of root lice, the thief ant exploits related species. This mini ant steals prey, eggs, larvae and pupae from its host animals. Both species do not target human habitation.
Pharaoh ant (Monomorium pharaonis)
The workers of this tiny ant are about two millimeters long and are amber-yellow in color with a dark abdomen tip. The chest and abdomen are connected by a stalk on which two conspicuous humps are formed. Male insects are black in color and slightly larger. The queen reaches a size of up to 4.5 millimeters and appears slightly darker than the workers. The species was introduced from Asia and has developed into a global cultural successor.
Pharaoh ants live here:
- in buildings with consistently high temperatures
- heated greenhouses, commercial kitchens and bakeries
- after introduction into private households
The species is active not only in summer but all year round and does not survive the winter outdoors. It is an omnivore that prefers to eat foods containing protein and sugar. The insects pose a problem in hospitals because they are attracted to blood and pus and transmit diseases. Fighting them is difficult because the nests are hidden. Feeding poisons with a long latency period promise the greatest success because these are carried into the nest and fed to the brood and queen.
Bicolor to multi-colored ants
It is not always possible to divide them into mono-colored or multi-colored species. If you don't find your species in this category, you should look at the monochromatic species. Different color casts and characteristics are also possible within one species.
Brown black carpenter ant (Camponotus ligniperdus)
The brown-black carpenter ant sometimes gets lost inside
This species is characterized by a shiny body. The head and most of the abdomen are black in color, while the front abdominal segment, stalks and legs are reddish-brown. The carpenter ant prefers significantly warmer locations than the related black carpenter ant. It inhabits dry and sunny deciduous and mixed forests. Occasionally it can be found on bushy dry grassland and on field verges.
Nest building:
- preferred in soft deadwood
- Tree trunks at heights of up to three meters and close to the ground
- pure earth nests are possible
- does not colonize living wood
Occasionally the species is considered a house ant. If it occurs in close proximity to human settlements, it can also occur in buildings. It nests in built-up wood of houses, sheds or bridges and builds nests in fence posts.
Bicolored garden ant (Lasius emarginatus)
The species is considered a typical house and garden ant, although the heat-loving ant is often confused with Larius brunneus. It is also known as the red-backed house ant because the breast has a red-yellow to red-brown color. The head and abdomen are dark brown and stand out clearly from the chest.
The warmth-loving species is mainly found in southern parts of Germany. She builds her nests in cracks in rocks, under stones and in rotten dead wood. Since the ants prefer rocky biotopes, settlement areas sealed with concrete and stones also appear extremely attractive. They can nest in house walls and cracks or in the beams if these nesting places have already been damaged by insects and fungi.
Flying ants
Winged ants are not a separate species. In an ant colony there are workers, queens and males. While in some species only males are winged, there are few related groups with winged queens. The formation of the wings has an evolutionary background. This enables the insects to reach mating partners outside of their colony.
If you observe ants with wings crawling out of a niche, this does not indicate that they are actively breeding in the house. The males look for partners from other colonies to perform their nuptial flight.
What really helps against ants?
If you want to get rid of ants, you should eliminate the causes of the infestation. It is not enough to distribute home remedies on the ant trails. Such measures provide short-term relief, but after a short time the insects are no longer impressed or look for alternative ways into the house. Put your focus on the nest.
Pull away
If you want to get rid of ants, you have to follow the ant trail to its end. This is where the nest is located. The ants living there do not like disturbance and will protect their brood if the nest is disturbed by intense smells. Therefore, herbs such as chervil, lavender or thyme are ideal for scaring away. Vinegar also helps to disrupt the insects’ sense of direction. When the aromas have disappeared, the effect is no longer effective. Therefore, you should add fresh herbs, vinegar or tea tree oil directly to the nests every day.
Tip
Coins or building materials made of copper are unlikely to be successful in fighting ants. Only biocides containing copper are effective, but they can cause serious damage to water bodies and other living beings.
Attract
Use various means to attract the insects. You can fill these with toxic substances. Baits work best in spring, before the plants sprout and leaves or roots are infested with lice. At this time, ants are already looking for food and readily accept sweet liquids and attractants. Later in the year, the insects continue to use the building as a nesting place if they have already settled here. They then prefer to look for food outside.
Suitable bait:
- Liver sausage
- Tuna
- Sugar water
- Beer and liqueur
Ants can be successfully controlled with poisonous traps
Eliminate
Sticky traps are only partially suitable for combating ants because they cannot catch all ants. Natural home remedies such as baking soda are also not suitable remedies. In order for baking soda to have its effect, you must dust the ants thickly with the raising agent. If the insects ingest the smallest particles through cleaning, they die. Baking soda changes the pH value and does not cause it to burst, as is often assumed. This method is quite effective for isolated ants in the house.
Relocation
The flower pot trick doesn't help much with ants that have settled in the house. A clay pot filled with nesting material is accepted when the actual nest is in danger or has been disturbed. To do this, the pot must be placed directly over the nest so that the ants can carry their brood into the new home. This is difficult to do if ants have settled in the walls. Therefore, such relocation attempts are only successful with species that have built a nest in the lawn.
Poison
If there is a massive infestation of ants, only poison can effectively combat the plague and destroy all ants. You should generally avoid sprays, as they spread the toxic ingredients into the air. Feeding poisons, which are applied as powder and eaten by the ants, are more suitable. Fipronil has proven to be an effective remedy. The biocide has a long latency period, meaning that the queens and brood living in the nest are also poisoned.
Avoid resettlement after successful control
Individual ants do not pose a problem. If the insects have settled throughout the house, the damage caused by ants in the house can be considerable. Identifying nests is the first thing you should do. Possible damage must be repaired, because after eradication, new colonization in the existing nesting areas is very likely.
If you want to permanently get rid of ants and fight them effectively, you should replace damaged insulation and beams and renovate walls. This deprives the ants of an important source of life and eliminates traces of scent. This is the only way to ensure that no new colonies migrate from outside.
Why do ants come into the house?
If you keep your kitchen free of sweet stains, you shouldn't have any problems with ants
Ant species populate different habitats in nature. These include cavities under stones, holes in the ground or rotten wood. Many buildings are designed so that the building materials are similar to natural nesting sites. This is why it happens that ants settle in cracks in facades, under terrace tiles or in built-up wood. When the insects follow ant trails in the house and apartment, they are looking for food. They come into the interior through leaky windows and doors or other gaps through the facade. Ants can appear in the house all year round.
Preferred food:
- Sweets
- Meat and Cheese
- Fruit and bread
Excursus
The Ant Algorithm
When an ant encounters a new food source, it consumes food and crawls back to its burrow. On the way back, the insect sprays out pheromones to mark the way. Once home, it regurgitates bits of food to stimulate its roommates. They set off and follow the scent trail. They also use numerous scents on the way home to make it smell even stronger.
First, the ants find their way to the food source based on the scent marks present. Since these still have a faint scent, other ants also get their food via other routes. The insects that have found the shortest route return to the nest more quickly. The pheromone concentration is now highest on the shorter path, which is why the following insects prefer this path. An ant trail has emerged.
Ants are not primary wood destroyers
The insects are not considered wood destroyers in the strict sense because they cannot use the fibers as food. Some species that specialize in dead wood only use it as a nesting substrate and colonize cavities and tunnels created by wood-decomposing fungi and pest insects. If they settle in built-up wood, then they prefer to use dilapidated and previously damaged wooden components. The different degrees of hardness of the wood are effectively utilized. Early wood parts can be easily cleared out, while the late wood remains as walls between the chambers.
Stray Ants
Ants can get into the house through flower pots
Occasionally it happens that ants build nests in the flower pot on the house. The colony can be transported into the house unnoticed if the bucket is brought into the basement to overwinter. Therefore, you should check the substrate thoroughly. If ants have settled, you can effectively combat them with water. In the immersion bath, the passages are flushed so that the ants and their brood escape.
When ants settle in wood
Direct destruction of wood materials by ants is still possible, although the ants do not primarily target buildings and intact wood. The building materials often offer completely innovative nesting opportunities for the insects with optimal conditions for raising brood. Thermal composite systems moistened by splash water are an ideal nesting substrate. They ensure a perfect climate that is similar to the conditions in dead wood.
Ants are influenced by progressive developments. They move with the times and use new nesting opportunities in insulated facades.
Indications of ant nests
The search for evidence provides quick information about whether an ant nest is likely in the house and apartment. Ants appear for a reason. They need optimal living conditions near the house and first have to find the way in. These signs increase the likelihood that an ant colony has settled in the house. Despite affirming these aspects, it may happen that individual ants have only gotten lost in the kitchen and bathroom.
Where ant nests are likely
- Facade insulation: Base area in contact with the ground and overgrown with dense vegetation
- Half-timbered house: surrounded by a densely planted vegetable garden
- Partition walls: in damp bathrooms and cool bedrooms, wooden beams pre-damaged by fungi and insects
Tip
The German Ant Protection Observatory e. V. has numerous regional associations in which volunteer ant experts provide their help.
Check house and apartment
If you regularly come across small piles of flour from sawdust, mortar or insulation material while cleaning, an insect infestation is likely. This assumption is supported if you find remains of insect bodies in the piles. However, dead ants on the ground do not necessarily indicate a pest infestation.
If the building is partly or entirely made of wooden beams, it offers potential nesting opportunities for ants. These nesting sites are even more attractive the wetter they are. Therefore, ant nests often occur near sources of moisture such as bathrooms, kitchens or winter gardens, where the building structure has a higher moisture content in the wood.
Check environment
For ants to find their way into your house, they must already find good living conditions in the area. An adjacent forest, dense vegetation directly on the house facade or a garden can be used as evidence. There must be a direct connection between the house and the garden that appears attractive to ants.
Frequently asked questions
Where do ants in the house come from?
Ants in the house do not always mean a new colony will be established
If you suddenly find ants in the house, there could be various reasons. Ant colonies often migrate from outside and settle in prefabricated nesting areas. This is the case if an old tree is felled nearby or a shed is torn down. You find these places via scent trails of old ant trails or are attracted by sweet scents.
A new colony founded by a queen directly in the house is rather unlikely. It is possible that ants accumulate in the house after rain. These are often terrestrial species that nest directly adjacent to the house. If the nest is flooded, the insects try to save their brood to dry land.
How can I avoid ants in the house?
If ants become a nuisance in the house and garden every year, simple tips can help. To prevent ants from entering the building, all entry gates should be closed. This includes not only visible gaps under windows and doors but also underground cracks on the facade. Here, earth-dwelling ants can easily get into the insulation. Strips containing contact poisons can be applied where sealing is not possible.
Is pest control by exterminators worth it?
If you decide to hire a pest controller, you should be informed in detail about the procedure. A professional exterminator has species knowledge and will identify the species before taking action. Using this information, he can assess whether the ants could actually have settled in the house. Specialists check the rooms for possible traces and seal entry gates. Gels or long-term remedies applied indiscriminately usually do not promise success.
What do ants feed on in the house?
The food spectrum of ants is broad. Many species feed on honeydew, while other ants are omnivores. In the house, they target foods containing sugar and protein. They eat fruit, meat and cheese or breadcrumbs.
