The varied carpet beetle, Anthrenus verbasci, is a 3mm-long beetle belonging to the family Dermestidae. This beetle can be a serious household pest and a pest in natural history museums, where it can damage biological specimens. While adults are pollen grazers, larvae feed on natural fibers and can damage carpets, furniture, clothing and insect collections.
The larva of this insect is what does the most damage. They are known as ‘woolly bears’ due to their banded appearance and are covered in short bristles (4mm-5mm long, are squat, brown in colour). The adults are 2mm-3mm long and the body is of a variegated pattern with a dense covering of scales. The adult beetle, on emergence, seeks out light and flower nectar. The adults mate and the female then go in search for a suitable material on which to lay their eggs.
Colour: Variable (pale brown, yellow and straw scales)
Size: Adult 2mm-3mm long (larvae up to 5mm long)
Region: Throughout Australia
Eggs are laid singularly within carpet, clothing, fur and museum material, they are 0.5mm long and are cream in colour. They hatch after ten days at 30°C, however in cooler temperatures they hatch after two to four weeks and the larvae feed till winter, in some conditions they will even hibernate if it is too cold. They resume feeding in the spring and then pupate. When fully grown they are 4mm-5mm long and normally moult 6 to 15 times. Pupation is within the last larval skin and usually lasts for 10 to 30 days. The adults live for two to six weeks.
The varied carpet beetle larvae are negatively phototaxic and will live exclusively on and in their foodstuffs. The adults are positively phototaxic and will actively fly to find flowers outside in the domestic environment. The beetle can sometimes be found on window sills attracted to UV light. This insect is common within bird’s nests.
The larvae will feed on substances that contain keratin, most commonly they are found within natural wool/wool mix carpets along the edges and in the corners. It is common to only find an infestation when an item of furniture is moved and a patch in the carpet is found.
Ensure that any old or existing bird nests within roof spaces are removed and the area treated with a residual insecticide. Hot water cylinder cupboards should also be checked regularly for signs of infestation. Carpets should be vacuumed thoroughly on a regular basis, and ensure that large furniture is moved aside to get to the corners and edging of carpets. Signs of a varied carpet beetle infestation can be controlled by the use of a residual insecticide.