Varied Carpet Beetle
Lat. “Anthrenus verbasci“
species
of family
“Skin Beetles“
1 species
The varied carpet beetle (Anthrenus verbasci) is a 3 mm-long beetle belonging to the family Dermestidae. They are a common species, often considered a pest of domestic houses and, particularly, natural history museums, where the larvae may damage natural fibers and can damage carpets, furniture, clothing, and insect collections. A. verbasci was also the first insect to be shown to have an annual behavioral rhythm and to date remains a classic example of circannual cycles in animals.
Description
Adult A. verbasci range in length from 1.7 to 3.5 mm (0.07 to 0.14 in). 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.
Habitat
Anthrenus verbasci does not have a strict habitat preferences and can be found in many places, but like many species in the genus, it can be found both indoors and outdoors. Its typical habitat is usually open areas with many flowers and trees, but it can also be found in houses, bird nests and other places.
Activity and mating system
This species lives in colonies. They can often be swept off leaves or flowers as they forage and consume pollen and nectar from these flowers in warm weather.
As a mating they are polygynadrous (promiscuous) and mate with many partners. What is known is that mating lasts from 1 to 9 minutes and the adults do not require food or water to reproduce. The phenomenon occurs on flowers or host material. Before mating, females assume the characteristic headstand and release pheromones. When a male is nearby, he rises and during the process of positioning he extends his aedeagus and with slight movements from one side to the other a short courtship is performed. The male changes positions and orients himself in copulation. The mounting is short. After 15-20 days the female lays her eggs.
Egg stage
The eggs are laid in dy places, in bird nests in tree hollows where there are dead insects, or in dry dead insects, in dry dead animal parts or plant products, on window sills in houses. The eggs hatch after 15-14 days at 30 degrees and up to 28 days at 15. They are 0.025 mm in size and white, often stuck together.
Larval stage
The larval form of A. verbasci, commonly known as ‘woolly bears’ (a name shared with the larvae of Arctia caja and many other moths of the subfamily Arctiinae), measures up to 4–5 millimetres (0.16–0.20 in) in length. The larvae are elongated and densely covered in large setae (hairs). 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. The newly-hatched larva is 1 mm long (there are smaller ones). The body is white, somewhat transparent, but after the head the 1st, 2nd and 3rd segments are light brown, and the head is light rusty brown. The last segment is pointed with a small tuft of initially only 5 hairs at the end of the abdomen. They are white and small. The second instar is simply thicker with a wide abdomen slightly after the middle. The larva in the 3rd instar is already almost with the original colors of the species. Increased number of hairs on the abdominal end in a whole bundle and an orange head. The first three segments are brown. In the 4th stage, the size becomes 2.5-3 mm, the dark brown 3 segments of the last 4 become more distinct and the hairs change their color to light brown. The tuft of hairs on the last segment is now very clearly visible, and the upper hairs are pale yellowish, darkening towards the end. The head acquires its distinctive orange color for the earlier stages. In the fifth instar, the length remains 3 mm, which means that the elongation is not particularly significant, unlike in the fourth instar, where the last stripe on the hair bundle is white, in the fifth it is dark. The three brown stripes on the upper part lighten. The head and especially the pronotum acquire a slight orange tint. The hair bundle darkens. In the sixth instar, the size is already 3.5 mm. The larva has a compact body and has grown a little in width. The head has darkened to dark orange, and the first brown segments have darkened. The tuft of hairs is almost black. This stage is observed 6-7 days after the 5th instar. Most stages last 5 to 7 days in a controlled environment, but this varies depending on temperature and a number of conditions. Already in the 7th stage they reach 4 mm and are simply a more elongated version of the previous one. There are no new colors. Five or six days after the 6th, this one appears. The 8th is quite stocky and wide. It is still 4 mm. Very dark. The third segment is bleached and blends in with the color of the rest of the body. The body, however, is dark brown. The two white tufts of hair at the back of the body are fading. In the 9th stage, the 4th and 5th abdominal segments acquire a brown color. The body lightens and acquires a pale yellow color. The hairiness thickens, especially on the pronotum and the head. It, in turn, is already brown. The only think that makes a difference in the 10th stage is the abdomen, which expends significantly towards the 6th-7th segment. The two white stripes at the end of the abdomen are enlarged and darkened to yellow. In the 11th stage there are not many changes, it is simply longer than the previous one and the coloration of the first segments is more distinct. At these stages, the colors of the larva have already formed and they simply differ in the intensity of the colors. The head looks so small because the abdomen is growing in size. The 12th instar larva is distinguished by its significantly increased number of hairs. In the 13th stage, the larva is noticeably wider and larger, and its overall darkening is noticeable. It also has a very long hair on its back. In the 14th instar, the penultimate segment has a white stripe that is very clearly visible. The next two segments after the pronotum fade in the middle (a sign of a late stage). The 15th instar is a larger version of the previous one and the 16th is the last with the original larval colors.
Distribution and 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.
Diet and behaviour
Larvae feed on keratin and chitin of natural fibers (dead insects, animal hair and feathers) 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, or trigger, being photoperiod. Adults feed on the pollen and nectar of flowering plants. They are reportedly particularly fond of flowers in the daisy family.
External links
Biolib Fauna Europaea Invertebrate Ireland on line Archived 2012-03-18 at the Wayback Machine Dermestidae of the World Habitus, abdomen and antennae. Varied Carpet Beetle Fact Sheet Varied Carpet Beetle Allergy and Treatment Archived 2016-09-27 at the Wayback Machine Museumpests.net - Varied Carpet Beetle Museum factsheet Dermestid Beetle Carpet Beetles and Clothes Moths Varied Carpet Beetles feeding on allium flowers Wikispecies Data related to Varied carpet beetle at Wikispecies
Ancestry Graph
Further Information
Copyright
This article uses material from the Wikipedia article Anthrenus verbasci the free encyclopedia Wikipedia which is released under Creative Commons Attribution-ShareAlike 4.0 International License). On Wikipedia a list of authors is available.