• Spider Beetle Beetles

    Spider Beetle
  • Spider Beetle
  • Spider Beetle


In the event of a spider beetle infestation, you should check areas of the building where waste can accumulate. The first thing to do is to remove all possible food sources for these insects. An application of Maheu&Maheu Insecticide Dust is recommended, and a liquid insecticide such as Maheu&Maheu Crawling Insect Killer should be sprayed around the perimeter of rooms and in easily accessible areas. The powder allows you to treat hard-to-reach areas such as structural spaces, for example, walls, attics, underneath the bath, false ceilings, electrical plugs, around pipes, etc.


  • Spray or treat room perimeters with an insecticide wherever insects have been found
  • Apply insecticide dust to structural voids and roof spaces if a lot of insects are getting in


  • Store food in sealed containers
  • Avoid putting rodenticides in structural voids when there is rodent infiltration

Description and development

Spider beetles (family Ptinidae ) are small, reddish-brown, holometabolous insects that are often mistaken for spiders because of their highly convex, rounded body and long legs. The abdomen resembles the ornamental head of a pin, and their antennae are long and slender. Spider beetles measure 1.5 mm to 3.5 mm long.

Below are the three most common genera of spider beetles:

1. Mezium: The head and thorax are covered with hairs and the hind trochanters are short. The most common species is the American spider beetle (Mezium americanum ).

2. Gibbium: Resembles the genus Mezium, but the hind trochanters are long and the head and thorax are smooth and shiny like the abdomen. The most common species in Quebec is probably the shiny spider beetle (Gibbium psyllioides ).
3. Ptinus: The thorax often bears tufts of hairs and the elytra (rigid wings) are grooved. The white-marked spider beetle (Ptinus fur ) is a member of this genus.

No data is available on the spider beetle life cycle. The larva is whitish, except for the head, which is yellowish with dark brown mouthparts. The larva is completely covered in long, fine hairs. Its size varies from 0.5 mm (at hatching) to 3–4 mm just before the pupal stage. The whitish to light brown pupa measures about 3.5 mm. It is protected by a cocoon made of silk mixed with fine particles of whatever substance it is resting on.


Spider beetles feed on decomposing or dry animal and/or plant organic matter. They are often found in buildings that have been inhabited by rodents and/or birds. In the case of rodents, the spider beetles feed on old bait, droppings, and hair. In the case of birds, they feed on feathers and droppings. Spider beetles prefer hard-to-reach areas, but they can be found almost anywhere food is available, and sometimes in tremendous numbers.

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