Latin: Lasius umbratus
A yellow shadow ant is not just a yellow ant. There are many different yellow ants, all belonging to the same genus, such as the ants Lasius umbratus, Lasius flavus and Lasius mixtus. Many of these ants are common in Denmark.
But especially one species of yellow ant with the Latin name Lasius umbratus will often appear indoors, where it can be a troublesome guest. And it is this species that the following refers to.
Appearance
The yellow shadow ant worker in the genus Lasius umbratus has a yellowish color and can grow up to 5.5 millimeters long. The queen does not share color with the worker ants but has a more reddish-brown color. In addition, she can grow up to eight millimeters long.
Biology and behavior
The yellow shadow ant is part of a large and complicated underground community that is often planted between the roots of trees that stand on their own. From the anthill originate numerous underground passage systems that can be meters long and reach all the way to the plant’s roots. The small worker ants rarely see the light of day but work fiercely underground.
The yellow shadow ants live mainly by milking the small root lice that occur around the roots of the plants. The ants feed on the sugary excrement of the root lice, also called honeydew, which is derived from the sap from the roots of the plant. However, the yellow shadow ant can also eat other small insects.
During the summer, winged males and females develop in the nest, moving up from the nest in July and August to mate. They can occur in large numbers when the mating season is on the highest level. If you have an anthill under the floor or under the terrace, you will probably experience how they swarm in the thousands at the same time every day. The males’ duty is quickly expired, and after mating they die.
Sometimes the queens break up with the colony to found new anthills. To that end, she and her followers like to invade other ant habitats, and it is often the black garden ant’s nest that gets invaded. Although the two species share kinship, the yellow shadow ant does not show any mercy towards the black ants. The queen of the yellow shadow ant kills the queen of the black ants and exploits the workers of the black ants to found her own colony.
Damage
When the yellow ant settles down and builds nests in houses, it most often happens under the floor or in connection with other woodwork. Here they start digging material such as gravel and soil from the subsoil, which the underside of the wood thereby encounters. At the same time, the ants produce water that also damages the wood, which can eventually be damaged by moisture and soften.
For the yellow shadow ant, the tree does not constitute a tempting meal. Instead, they dig the passages in the softened wood, causing an erosion of the wood and leaving it destroyed. The results of their efforts are bad enough to be recognized as being wood. For the assembled wood is transformed – together with other parts such as sand grains, insulation material and plant fibers – into a cardboard nest that most of all evokes memories of a sponge.
Prevention and pest control
Unfortunately, it is not possible to prevent any attacks from the yellow shadow ant in the house. In fact, it can often be difficult to track down an attack from these unwanted guests before they practically walk through the floor into the residence. For the ants rarely show up in the home itself. Therefore, it can be difficult to launch a fight before the ants have already done great damage to the material of the home.
However, it may be worth keeping an eye out for traces of the yellow shadow ant. And here, a dark staining of delimited floor sections can be a good gossip handle for whether there should be an ant colony under the floorboards. At the trail of flying ants in the house, one should also be on guard.
Control of the yellow shadow ant is best tackled by locating the ants’ nest and removing and destroying their nests. Here, a dark staining on the floor as described can be a good indicator. The infested woodwork as well as the nearby woodwork should be treated with a liquid wood preservative against wood-destroying insects. All holes near the nest should also be dusted with an insect repellent.
Unfortunately, ordinary bait cans and poison paint have no effect on the yellow shadow ant, so it can be a difficult task to try to fight the ants. At the same time, it often requires that one is forced to break the floor up. The yellow shadow ant does normally not move inside the home but stays hidden under the woodwork. However, should a stray winged yellow ant appear inside the house, it can be easily removed with the vacuum cleaner or controlled with insect spray for flying insects. If they occur in large numbers, you should thoroughly inspect the house.
"Pests in House and Home"
"Bed Bugs - Bites, Stings and Itches"
"Food Pests"
"Husets dyreliv" (Insects Around the House - Only danish)
"Skadedyr i træ" (Timber Pests - Only danish)
"Stuefluen" (Common Housefly - Only danish)