Varied carpet beetle
Encyclopedia
The varied carpet beetle (Anthrenus verbasci) is a 3 mm–long beetle
that can be a serious household pest. It feeds on natural fibers and can damage carpets, furniture and clothing.
The larval form is known as a woolly bear, a name it shares with the larvae of Arctia caja and many other moths of the family Arctiidae.
A. verbasci was the first insect to be shown to have an annual circadian rhythm
and to date remains a classic example of circannual cycles in animals.
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The larval form of A. verbasci are roughly 4–5 mm (0.15748031496063–0.196850393700787 ) in length. The body is covered in a pattern of alternating light- and dark-brown stripes. The body is usually wider at the back than at the front and also bears 3 pairs of hair tufts along its rear abdomen that can be used for self-defense.
Adult A. verbasci range from 1.7 to 3.5 mm (0.0669291338582677 to 0.137795275590551 ) in length. Their dorsal surface has scales of two colours, whitish and yellowish-brown. White scales are condensed along the lateral margins of the pronotum. In addition, their antennae are 11-segmented with a club of 3 segments.
and House Swift
) or around stored fabrics. Larvae feed on natural fibers throughout their development, eventually experiencing a dormancy period (also known as diapause
) prior to pupation into the adult stage. The length of the dormancy appears to depend on environmental factors, with the most likely zeitgeber
being photoperiod.
Adults emerge between late May and early August, flying to and feeding on the pollen of flowering plants. During this period, mating occurs, eggs are laid, and the cycle begins anew.
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. Such a defense, however, has been shown to be effective for the closely related species Anthrenus flavipes, which has slightly longer hairs than A. verbasci.
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 an adult wasp.
balls in closets, and removing abandoned bird and insect nests attached to the building. Signs of an infestation include the presence of damaged articles, molted larval skins in dark areas, and an abundance of adult beetles near windows. Deterring or killing A. verbasci can be accomplished using insecticides, oxygen deprivation, freezing, and pheromone
and scent traps.
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
that can be a serious household pest. It feeds on natural fibers and can damage carpets, furniture and clothing.
The larval form is known as a woolly bear, a name it shares with the larvae of Arctia caja and many other moths of the family Arctiidae.
A. verbasci was the first insect to be shown to have an annual circadian rhythm
Circadian rhythm
A circadian rhythm, popularly referred to as body clock, is an endogenously driven , roughly 24-hour cycle in biochemical, physiological, or behavioural processes. Circadian rhythms have been widely observed in plants, animals, fungi and cyanobacteria...
and to date remains a classic example of circannual cycles in animals.
Identification
Adult A. verbasci range from 1.7 to 3.5 mm (0.0669291338582677 to 0.137795275590551 ) in length. Their dorsal surface has scales of two colours, whitish and yellowish-brown. White scales are condensed along the lateral margins of the pronotum. In addition, their antennae are 11-segmented with a club of 3 segments.
Life cycle
A. verbasci has an unusual life cycle for an insect, developing from larvae to adult in 1–3 years, depending on the environmental conditions. Larvae hatch from eggs in the spring and early summer, often in the nests of birds (including those of the House SparrowHouse Sparrow
The House Sparrow is a bird of the sparrow family Passeridae, found in most parts of the world. One of about 25 species in the genus Passer, the House Sparrow occurs naturally in most of Europe, the Mediterranean region, and much of Asia...
and House Swift
House Swift
The House Swift is a species of swift in the Apodidae family.It is found in Nepal, and Southeast Asia. It was formerly considered a subspecies of the Little Swift.-References:...
) or around stored fabrics. Larvae feed on natural fibers throughout their development, eventually experiencing a dormancy period (also known as diapause
Diapause
Diapause is the delay in development in response to regularly and recurring periods of adverse environmental conditions. It is considered to be a physiological state of dormancy with very specific initiating and inhibiting conditions...
) prior to pupation into the adult stage. The length of the dormancy appears to depend on environmental factors, with the most likely zeitgeber
Zeitgeber
Zeitgeber is any exogenous cue that synchronizes an organism's endogenous time-keeping system to the earth's 24-hour light/dark cycle. The strongest zeitgeber, for both plants and animals, is light...
being photoperiod.
Adults emerge between late May and early August, flying to and feeding on the pollen of flowering plants. During this period, mating occurs, eggs are laid, and the cycle begins anew.
Predators
Among the natural predators of A. verbasci, one of the most well-studied is the parasitoidParasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...
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
Ovipositor
The ovipositor is an organ used by some animals for oviposition, i.e., the laying of eggs. It consists of a maximum of three pairs of appendages formed to transmit the egg, to prepare a place for it, and to place it properly...
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. Such a defense, however, has been shown to be effective for the closely related species Anthrenus flavipes, which has slightly longer hairs than A. verbasci.
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 an adult wasp.
Interaction with humans
The larvae of A. verbasci is a common household pest. Adult beetles usually lay their eggs in air ducts, in closets, under furniture, or under baseboards. Once hatched and until they pupate into adults, the larvae hide in dark, undisturbed areas and feed on organic material. The larvae are thus responsible for the damage of various items, such as furniture, clothing, blankets, furs, and carpets. Collections of specimens, especially of insects, are also vulnerable to attack, making A. verbasci a common pest in museums. Infestations can be prevented by regular vacuum cleaning, dry cleaning or airing clothing outside, placing naphthaleneNaphthalene
Naphthalene is an organic compound with formula . It is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings...
balls in closets, and removing abandoned bird and insect nests attached to the building. Signs of an infestation include the presence of damaged articles, molted larval skins in dark areas, and an abundance of adult beetles near windows. Deterring or killing A. verbasci can be accomplished using insecticides, oxygen deprivation, freezing, and pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
and scent traps.
External links
- Dermestidae of the World Habitus, abdomen and antennae.
- Varied Carpet Beetle Fact Sheet
- Dermestid Beetle