July 8, 2025, 8:42 am | Read time: 4 minutes
He is one of the most persistent pantry pests in German households and businesses, yet he is not widely known. We’re talking about the Australian spider beetle. myHOMEBOOK provides information on its spread, control, and prevention of infestation.
“Ptinus tectus” is the Latin name for the Australian spider beetle. While it doesn’t actually steal anything, it has spread significantly in Germany since its introduction. It is versatile in its diet and difficult to combat.
How the Australian Spider Beetle Became Established in Germany
The Australian spider beetle likely made its way to Germany around the year 1900. Originally from Australia and Tasmania, it was introduced via trade routes. Since then, the beetle has settled throughout Germany and is found in all federal states. The species is nocturnal and unable to fly, relying on “passive” transport, such as in trade goods.
Because the beetle has found a home in Germany for more than 100 years, an infestation does not need to be reported to authorities. The Federal Office of Consumer Protection and Food Safety (BVL) only monitors the species generally. The beetle has thus earned something like a right to stay due to its persistent nature.
The Life Cycle of the Australian Spider Beetle
Optimal living conditions for the beetle, which is between 2.5 and 4 millimeters in size, are temperatures of 23 to 25 degrees Celsius. Under these conditions, the beetle can develop from egg to adult in just over 60 days. In Germany, the species has spread because, unlike other tropical species, it can also develop at temperatures below 10 degrees Celsius, albeit more slowly.
The female lays between 100 and 120 sticky eggs, from which larvae hatch after a maximum of 16 days. These larvae undergo several molts within six weeks before pupating. The beetles then emerge from the cocoons. The beetle itself can live up to 12 months, during which a female can produce up to 1,000 eggs.
What Does the Pest Eat?
The Australian spider beetle is, to put it positively, not a picky eater, a trait known biologically as polyphagy. Hardly any organic material is safe from it. While it prefers wheat, it also consumes dried fruits, pepper, or wool. It attacks documents and even consumes dead insects or rodent droppings.
Infested food is no longer suitable for human consumption due to contamination by droppings. For museums that display stuffed animals or house insect specimens, an infestation is a nightmare. For the beetles, however, it’s a paradise.
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Infestation Not Easy to Detect
An infestation with the Australian spider beetle is hard to detect. For one, as a nocturnal species, the beetle hides in cracks and crevices during the day. And if it does catch the eye, it might quickly be dismissed as harmless. When threatened, the insects play dead. To discover an infestation, one must look closely. Typical signs of infestation include:
- round exit holes of 1 to 2 millimeters in infested materials
- brown droppings
- round, silk-like cocoons of the larvae
The larvae are cream-colored. More relevant for experts: When disturbed, they curl up, which trained individuals can recognize. The beetle itself looks spider-like. Its compact body has six long, thin legs. There is a constriction at the neck, which is also typical.
Home Remedies Are Not a Solution
Once settled in a home, the pest is difficult to get rid of. Professional pest controllers combine various measures.
In addition to using insecticides, thermal treatment is effective. Infested materials are heated to at least 50 degrees Celsius for several hours. Temperatures above 38 degrees Celsius over an extended period are also lethal to adult beetles.
Low temperatures are also helpful. For minor infestations or smaller stockpiles, freezing at –18 degrees Celsius for 24 hours can kill the larvae.
Prevention Is Easier Than Combating
Getting rid of the Australian spider beetle is a complex task. As with all pests, prevention is better.
- Food should be stored in airtight containers.
- Storage areas should be regularly cleaned and kept dry.
- In businesses, incoming goods should be inspected.
- Additionally, it is advisable to store goods half a meter away from the wall, as the beetle cannot fly.
If there is a suspicion of possible infestation, setting up special bait traps (pheromone traps) can be useful. This is especially true in commercial operations or museums.
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Climate Change Favors the Australian Spider Beetle
The noticeable climate change in Germany benefits the beetle. Although the species can develop at lower temperatures, as mentioned, milder winters allow for more generations per year. The more our climate resembles the conditions of its original home, the better for this species.