Varied carpet beetle

Appearance

Adult "A. verbasci" range in length from 1.7 to 3.5 mm. The body is rounded, almost spherical. The elytra and pronotum are covered in fine scales of different colours, creating an irregular pattern of white, brownish and yellowish patches on these features. The white scales are focussed along the lateral margins of the pronotum and on the elytra, where they form three bright, wavy transverse bands. In addition to these morphological features, their antennae are 11-segmented, with a club of 3 segments.

The larval form of "A. verbasci", commonly known as 'woolly bears', measures up to 4–5 millimetres in length. The larvae are elongated and densely covered in large setae. These hairs are organised into alternating, transverse groups of light and dark-brown patches: the larva appears covered in brown stripes. The body is usually wider at the back than at the front where it also bears 3 pairs of hair tufts along its rear abdomen that can be used for self-defense.

Distribution

This species is present in most of Europe, in the eastern Palearctic realm, in the Near East, in the Nearctic realm, in North Africa and in North Asia, also in the Neotropics.

Behavior

"A. verbasci" has a life cycle ranging from 1–3 years, depending upon the environmental conditions. A study in 1958 found that temperature is able to affect larval development, concluding that the periods of incubation and pupation of "A. verbasci" decrease with increase of temperature. Incubation decreased from 54 days at 15 °C to 12 days at 30 °C, and the pupation decreased from 89 days at 10 °C to 9 days at 25 °C. Relative humidity was shown to have little effect.

Larvae hatch from eggs in the spring and early summer, often in the nests of birds or around stored fabrics.

Adults emerge between late May and early August, flying to and feeding on the pollen and nectar of flowering plants. The life expectancy of the beetle is about two weeks. During this period, mating occurs and the eggs are laid, either close to the human environs or in bird nests, tree hollows and similar, dry places where larvae can find their food. Then the cycle begins anew.Larvae feed on keratin and chitin of natural fibers throughout their development, eventually experiencing a dormancy period prior to pupation into the adult stage. The length of the dormancy appears to depend on environmental factors, with the most likely "zeitgeber", or trigger, being photoperiod. Adults feed on the pollen and nectar of flowering plants.

Habitat

This species is present in most of Europe, in the eastern Palearctic realm, in the Near East, in the Nearctic realm, in North Africa and in North Asia, also in the Neotropics.

Food

Larvae feed on keratin and chitin of natural fibers throughout their development, eventually experiencing a dormancy period prior to pupation into the adult stage. The length of the dormancy appears to depend on environmental factors, with the most likely "zeitgeber", or trigger, being photoperiod. Adults feed on the pollen and nectar of flowering plants.

Predators

Among the natural predators of "A. verbasci", one of the most well-studied is the parasitoid wasp "Laelius pedatus". Upon discovering an "A. verbasci" larva, a female wasp will land on the larva's dorsal side and attempt to line up its long, stinger-like ovipositor for a paralyzing blow to the thorax. In response, the larva will erect long hairs on their abdomen and attempt to brush these hairs against the encroaching wasp. The hairs detach and stick to the wasp on contact, presumably causing some sort of irritation. Evidently, such irritation is not enough to deter an attack on "A. verbasci" larvae, as the vast majority of attacks are successful. By comparison, the closely related beetle species "Anthrenus flavipes" – which has slightly longer hairs than "A. verbasci" – uses such a defense more effectively.

After a single successful sting, the beetle is permanently paralyzed. The entire process from landing to complete paralysis lasts approximately 40 seconds. "L. pedatus" does not lay eggs immediately after the beetle is paralyzed, waiting as long as 24 hours before oviposition. During this time, she grooms herself, removing any hairs that might have stuck to her during the attack. During this lengthy process she appears to monitor the larva's state of paralysis by repeatedly biting it and monitoring its reaction. Once sufficiently clear of hairs, the wasp creates a bare patch on the larva's abdomen and lays 2–4 eggs. Eggs hatch in 3–4 days and the larvae feed on the beetle for 3–7 days, eventually killing the host. They then spin cocoons near the empty shell of the host, emerging some time later as adult wasps.