Why are bed bugs so difficult to spot

The common bed bug

Unwanted roommates

The very thought of the crawling insects involuntarily triggers itching and disgust in most people.

"Bed bugs originally lived in caves and mainly fed on bats. When humans began to discover caves as a habitat, the little animals were happy about the new food source and moved with the host into huts and houses," says Dr. Reiner Pospischil, who, as a parasitologist, has to do with bed bugs - especially bed bugs and their control.

The little parasites live all over the world and they feed on blood. Preferably from human blood. Lured by the warm, humid air they breathe, they crawl out at night and feast on the sleeping.

Soaked - and thus twice as big and four times as heavy - they crawl back into their hiding place, leaving a trail of dark dots behind them.

Itchy wheals

Bedbugs appreciate the dark. During the day they crouch in the slatted frame or behind the baseboards, hide behind picture frames or crawl in cracks in mattresses. Radio alarm clocks and lamps are also popular hiding spots, because the animals like to be warm.

The bug sheds its skin five times from larva to imago, this is the name of the adult animal. Before each molt, the insect needs food. Bed bugs don't mind starving for over six months.

People only notice unwanted roommates when they are tormented by itchy wheals the next morning. "You don't even feel the suction process itself, and there are also many people who have lived with bedbugs for years and are bitten every night without knowing it," says bug researcher Reiner Pospischil. Because bedbug bites do not cause itching in everyone.

When it itches, the wheals become as big as the nail of the little finger and are often neatly next to each other in a row, also known as the street of bugs.

Although the sting does not hurt or transmit disease, it can itch for five days or more in sensitive people. In severe cases it can even lead to extensive skin inflammation and visual disturbances up to shock reactions in sensitive people.


In earlier times, the nuisances were mainly guests of the rich. Because only they could afford to heat their living spaces.

From the 1950s onwards, improved hygiene and insecticides kept the small bloodsuckers in check in the industrialized countries. However, the little animals were never completely exterminated, and since the turn of the millennium the number of bugs used by exterminators has increased again.

One of the reasons for this is the increased wanderlust: business people and tourists who fly all over the world and all over the world bring the parasites with them - without realizing it - as stowaways.

The tiny animals crawl into the roller bearings of trolley cases, hide in the zippers of travel bags or slip into the snap locks of the suitcases and only hop out again in Germany.

If you want to make sure that you have no unwanted travel souvenirs in your luggage, you should breathe into the locks immediately upon arrival. Because the carbon dioxide in the human breath lures the animals out of their hiding place.

If the bed bugs go unnoticed, they multiply quickly as the females lay up to twelve eggs a day. A strong infestation, which can also be recognized by the musty-sweet smell that the animals excrete, is always a case for the pest controller.