Dermestes lardarius
Finding a dark beetle near food cupboards, or a bristly larva in stored food or pet treats, can leave you wondering what it is and where it has come from.
Larder beetles feed on a range of animal-based materials and stored foods. The beetles or larvae may be coming from an infested product, but they can also be linked to a dead insect or animal, or an old bird or wasp nest. Finding the source helps decide what needs to happen next.
What does a larder beetle look like?
The adult larder beetle is an oval-shaped, dark beetle, usually around 7 to 10 mm long. Its most noticeable feature is a broad pale band across the front part of its wing cases, marked with dark spots.
The larvae look very different. They are elongated and brown, with bands of lighter colour and bristly hairs. Mature larvae can grow larger than the adult beetle. You may also find their shed skins near a food source or along a route they have travelled.
Other beetles can look similar, so a photograph can help with identification.
Why might I have larder beetles?
Larder beetles can feed on dried meat, cheese, pet food and other animal-based materials. They may also feed on dead insects and animal remains.
In a home, the source could be an infested food product or pet food. It might also be something less obvious, such as a dead animal or insects in a loft or wall space, or an old nest near the building.
The adult beetles and larvae may be found some distance from the original source. A beetle seen on a windowsill or wall does not always mean the food cupboard is where they are breeding.
A little about their life cycle
Larder beetles develop through four stages: egg, larva, pupa and adult.
The female lays eggs on or near suitable food. The larvae feed as they grow and shed their skins. When mature, they may move away from the food to find a sheltered place to pupate. They can sometimes bore into nearby soft materials, such as wood or plaster, while seeking a pupation site.
An adult beetle then emerges. How quickly the life cycle develops depends on conditions such as temperature and food supply.
What should I do if I find larder beetles?
Check dry foods and pet food, including treats, for beetles, larvae or signs of feeding. Discard any affected products and clean the cupboard, shelf or storage area thoroughly. Vacuuming can help remove insects, shed skins and food debris from cracks and corners.
Keep remaining food and pet food in sealed containers. If beetles continue to appear after the food storage area has been cleaned, there may be another source nearby. Don’t enter an unsafe roof space or dismantle building materials to search for one.
How Guardian can help
We’ll assess the beetle activity and its likely source, then advise on the treatment we consider necessary.
The right approach depends on what is infested and where the beetles are coming from. Treating visible beetles without dealing with an accessible source may not resolve the underlying problem. We’ll explain what we find and what we recommend.
Frequently asked questions
Are larder beetles harmful to people?
They are mainly a nuisance pest. They can contaminate stored products with droppings and shed skins. If you find beetles or larvae in food, discard the affected product.
Do larder beetles only live in food cupboards?
No. They can be associated with pet food, animal-based materials, dead insects, animal remains and old nests. The source may be away from the cupboard where you first noticed a beetle.
Why have I found a larva away from the food?
Mature larvae may leave their food source to find a sheltered place to pupate. Finding one elsewhere does not necessarily mean that it has been feeding in that particular spot.
Can larder beetles come from a dead mouse or an old nest?
Yes. Dead animals, dead insects and old bird or wasp nests can provide a food source. A professional assessment can help establish whether one may be contributing to the activity.
How does Guardian treat larder beetles?
We assess the beetles and their likely source, then advise on the treatment we consider necessary. The approach depends on the site and what is supporting the activity.
