Common Plaster Beetle

Pronunciation

How to pronounce Dienerella filum: //ˌdiːnəˈrɛlə ˈfiːləm//

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Summary

Dienerella filum, known as the common plaster beetle, is a small fungus beetle prevalent in damp indoor environments, where it feeds on mould. It is often found in places under renovation and can be associated with hygiene issues due to its infestation in poorly maintained areas.

Physical Characteristics

The adult common plaster beetle measures between 1.2 and 1.6 mm in length, is brown in color, and lacks hind wings, making it flightless. The antennae have a two-segmented club, unlike other members of the genus which have a three-segmented club. The head has a midline suture, and the thoracic shield has a wide, deep depression. The larva is whitish, reaching 1.7 to 2 mm, and the cream-colored pupa is about 1 mm long.

Identification Tips

Look for the two-segmented club at the tip of the antennae, lack of hind wings, and small size (1.2–1.6 mm). Adult beetles cannot crawl on smooth surfaces and may often be found trapped in sinks or tubs.

Habitat

Dienerella filum is usually found in damp environments within buildings, such as old warehouses, cellars, around leaking water pipes, and under loose wallpaper. It infests areas affected by mould.

Distribution

Native to the Palaearctic and adventive in the New World; reports from southern Canada and northern US extending to NY, AR, CO, and CA.

Diet

The diet consists of hyphae and spores of filamentous fungi, and spores of slime moulds.

Life Cycle

Females lay about twenty eggs during their lifetime in suitable spots. Development may take about five weeks at 24 °C (75 °F) but can take up to five months in colder conditions.

Reproduction

The female lays eggs singly in suitable environments, typically in damp conditions where mould is present.

Ecosystem Role

As a fungus beetle, it plays a role in the decomposition and recycling of organic matter, particularly decaying moulds.

Economic Impact

Potential pest of air-conditioning and refrigeration systems; associated with hygiene issues in hospitals due to infestations.

Health Concerns

Associated with hygiene problems in hospitals due to its presence in damp environments.

Collecting Methods

• Hand collection in habitats with mould
• Traps placed near infested sites

Preservation Methods

• Dried and pinned specimens
• Alcohol preservation

Misconceptions

Some may believe that its presence indicates poor hygiene, while it primarily thrives in damp conditions regardless of sanitation.

Tags

• Insect
• Beetle
• Fungus beetle
• House pest