Latin: Stegobium paniceum
In the family of borer beetles (Anobiidae) is the bread beetle found, which also goes by the Latin name Stegobium paniceum. But unlike many other members of the genus, the bread beetle cannot live in wood. Instead, it has a taste for starchy foods, hence the name.
When the beetle larvae hatch, they leave circular holes in the material they have lived in. And these holes are confusingly like the holes in a tree that has hosted the borer beetle larvae.
Bread beetles are not limited to one region, but are found all over the world. And often it is through shipping that the beetles are spread across the globe. Their history of shipping is not exactly good, as the bread beetles liked to be annoying and unwelcome guests on board the ships. This is not least due to their ability to plunder the crew’s meals. And it was often necessary to knock the bread on the table before they were ingested so that one could get rid of most of the bread beetles.
Appearance
An adult bread beetle has a rather small size. It will not be more than between 2 and 4 millimeters long. The beetle’s cover wings have a reddish brown color with stripes in, while the body is covered with small short hairs in a yellowish color. The head of the bread beetle is hidden under its neck shield. The bread beetle larvae grow up to about 5 millimeters long. They are c-shaped, are white-yellow in color, and in addition are equipped with rather small legs.
Biology and behavior
The life cycle of an adult bread beetle is not exceptionally long and lasts only up to 2 months. During this time, a female bread beetle can lay about 100 eggs. It takes between 1 to 2 weeks before the small larvae hatch from the eggs. The newly hatched larvae are extremely small and measure only about ½ millimeters. They therefore easily penetrate seals and packaging that are not properly sealed.
The larvae thrive best in very starchy and dry products such as pasta, biscuits, and crispbread. But they can also find their way into dried vegetables, spices, nuts or even pharmacy goods and animal feed where they can undergo their development. Once the larvae have eaten their fill, they become cramped and tired and can barely move. They can survive a week without consuming food. Unlike the larvae, the adult bread beetles do not take food.
As soon as the larva is fully developed, it pupates. It happens in a small cell, which it itself produces from the food that surrounds it, and which is put together with the larva’s saliva. Here the larva stays for a couple of weeks until it turns into a beetle and gnaws itself out, leaving a fly hole of 1-2mm in the food. The development from egg to adult beetle lasts between 2 to 6 months, depending on the conditions. The warmer the temperatures, the faster the development. If the temperature is between 20-22 degrees, the development from egg to adult takes approx. 120 days. The little bread beetle does not rest on its laurels. And already shortly after it itself is pupated, it even begins on mating and laying. Then the beetles fly towards the light and you therefore often find them in the windowsills.
Damage
The bread beetles usually cause harm to our food. As such, they are not a hazard to our health if ingested or stored in our foods, but they are also not very appetizing additives in either cooking or pantry.
The bread beetle larva is almost omnivorous, but feeds mostly on starchy plant products such as bread, seeds, spices, nuts, and pasta etc.
There have also been examples of them damaging books and stationery.
Prevention and pest control
When fighting the bread beetle, it is first and foremost a matter of finding the place where the larvae develop. Foods that have been attacked by the larvae should be discarded or processed. Since the bread beetle will search for the starchy products, it will normally be in the kitchen or pantry that one finds the hearth. But also make sure to search animal feed and treats for signs so that any outbreak is not overlooked.
Bread beetles and larvae can be killed by heating infected products at 60°C for about 10 minutes. It is also possible to get rid of the bread beetles by freezing, but it requires temperatures below -18°C for several days to get rid of all stages of the bread beetle, which is a lot more complicated.
In addition, you can control the bread beetle with insect spray. Please note, however, that this must not be used in areas where food is stored. Combine all types of treatment with a thorough vacuuming of several rounds, and discard the vacuum cleaner bag after use, so that the bread beetles do not crawl out again.
"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)