Coleoptera
Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...
that are commonly referred to as skin beetles or carpet beetles. Other common names include larder beetles, hide or leather beetles, and khapra beetles. There are over 1,800 species described.
Dermestids have a variety of habits; most genera are
scavenger
Scavengers are animals that consume Corpse decomposition, dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a he ...
s that feed on dry animal or plant material, such as skin or
pollen
Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...
, animal hair, feathers, dead insects and natural fibers. Members of '' Dermestes'' are found in animal carcasses, while others may be found in
mammal
A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...
,
bird
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
wasp
A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder ...
grain
A grain is a small, hard, dry fruit (caryopsis) – with or without an attached husk, hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and ...
.
These beetles are significant in forensic entomology. Some species are associated with decaying carcasses, which may help with criminal investigations. Some species are pests ( urban entomology) and can cause extensive damage to natural fibers in homes and places of business.
They are used in taxidermy and by
natural history museum
A natural history museum or museum of natural history is a scientific institution with natural history scientific collection, collections that include current and historical records of animals, plants, Fungus, fungi, ecosystems, geology, paleo ...
s to clean animal skeletons. Some dermestid species, commonly called "bow bugs", infest
violin
The violin, sometimes referred to as a fiddle, is a wooden chordophone, and is the smallest, and thus highest-pitched instrument (soprano) in regular use in the violin family. Smaller violin-type instruments exist, including the violino picc ...
Adult Dermestidae are generally small beetles (1–12 mm long), rounded to oval in shape, with hairy or scaly elytra that may form distinctive and colourful patterns. Except in genera ''Dermestes'' and '' Trichelodes'', there is a single ocellus in the middle of the head. The antennae are clubbed (except in male ''Thylodrias contractus'') and usually fit into a groove on the underside of the
thorax
The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen.
In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main di ...
, concealing them when the beetle is at rest. Adult females of ''T. contractus'' are notable for being larviform, meaning they retain a larval morphology even into adulthood.
Larval Dermestidae range from 5 to 15 mm long and are usually covered in tufts of long, dense hairs (
seta
In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms.
Animal setae
Protostomes
Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae, ...
e). In subfamily Megatominae and the genus '' Trinodes'', some of these setae are hastisetae: barbed setae ending in spear-like heads ('' hasta'' being the Latin word for "spear"). Hastisetae serve a defensive role, detaching and entangling predators.
Pupae of subfamilies Dermestinae and Attageninae are covered in structures known as gin-traps, as defense against predators. Pupae of Megatominae are protected within the
exuviae
In biology, exuviae are the remains of an exoskeleton and related structures that are left after ecdysozoans (including insects, crustaceans and arachnids) have molted. The exuviae of an animal can be important to biologists as they can often be ...
of the last larval
instar
An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...
.
Diet and behaviour
Dermestid larvae are typically found on dry organic items that are hard for other organisms to digest, such as dried foodstuffs, skins, hides, wood and other natural fibers. In forensic studies, the larvae are found on human corpses during the dry and skeletal phases of
decomposition
Decomposition is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is ess ...
, which occurs several days after death. Larvae also move away from light and often hide in any cavity in order to remain undisturbed. In natural habitats, they can be found on animal carcasses, under bark, and in the webs,
nest
A nest is a structure built for certain animals to hold Egg (biology), eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of ...
s and
burrow
file:Chipmunk-burrow (exits).jpg, An eastern chipmunk at the entrance of its burrow
A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of Animal lo ...
s of various animals.
Larvae of subfamilies Dermestinae and Attageninae (which lack hastisetae), burrow into feeding substrates, pupate in concealed locations, and show fast escape behaviours when disturbed. Larvae of Megatominae (which have hastisetae), do not burrow, pupate where they have been feeding, and their response to disturbance is to stop moving, arch the body and spread the hastisetae. This difference may be because hastisetae would be a hindrance for burrowing larvae.
Adult dermestids are known to feed on
pollen
Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...
and
nectar
Nectar is a viscous, sugar-rich liquid produced by Plant, plants in glands called nectaries, either within the flowers with which it attracts pollination, pollinating animals, or by extrafloral nectaries, which provide a nutrient source to an ...
. Adults of ''Dermestes'' are cannibalistic and will eat young larvae and pupae; this means that when kept in captivity, adults should be placed in separate containers from the immature stages.
Economic relevance
Urban and stored products
Dermestid
beetles
Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...
are destructive to a number of common items. Natural fibers such as wool, silk, cotton, linen, fur, or feathers are much more prone to attack than synthetic fibers. Dermestids also attack chocolate, copra, and cocoa beans.
Medical
Dermestid hastisetae (a specific group of detachable
setae
In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms.
Animal setae
Protostomes
Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae ...
from the larvae of subfamily Megatominae), both those attached to
exuviae
In biology, exuviae are the remains of an exoskeleton and related structures that are left after ecdysozoans (including insects, crustaceans and arachnids) have molted. The exuviae of an animal can be important to biologists as they can often be ...
and those shed by larvae, cause health problems in humans when inhaled ( rhinoconjunctivitis,
asthma
Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...
), ingested in contaminated food (
nausea
Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. It can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the throat.
Over 30 d ...
,
fever
Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with Human body temperature, body temperature exceeding the normal range caused by an increase in the body's temperature Human body temperature#Fever, s ...
,
diarrhea
Diarrhea (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration d ...
, proctitis, perianal itching) or touched with skin (
dermatitis
Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...
).
Forensic
''Dermestes maculatus'', hide beetles, also have the potential to offer investigators an estimation of the time since death in homicide or questionable cases. Similar to the use of flies in forensic entomology, the arrival of ''D. maculatus'' to
carrion
Carrion (), also known as a carcass, is the decaying flesh of dead animals.
Overview
Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
occurs in a predictable succession. Adult ''D. maculatus'' beetles generally arrive 5 to 11 days after death. In an attempt to refine this relatively wide range, recent research has repeated arthropod succession studies. These studies are applied to estimate the arrival of various species of Dermestidae after death. Development for dermestids is temperature dependent, and the optimal temperature for ''D. maculatus'' is 30 °C. Development data is normalized using Accumulated Degree Days. Dermestids can also be used in cases involving entomotoxicology, where feces and shed larval skins can be analyzed for toxins.
''Dermestes maculatus'' collected from raccoon carcass:
Image:Dermestidae 1.jpg, Lateral view ''(Dermestes maculatus)''
Image:Dermestidae 2.jpg, Head view ''(D. maculatus)''
Image:Dermestidae 7.jpg, Ventral view ''(D. maculatus)''
Image:Dermestidae 6.jpg, Dorsal view ''(D. maculatus)''
Evolution
While possible members of the family have been described from the
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch a ...
and Early Jurassic based on isolated elytra, the oldest known unambiguous member of the family is ''Paradermestes'' from the Middle Jurassic Jiulongshan Formation of China, which appears to belong to the subfamily Dermestinae. Members of the subfamilies Attageninae and Megatominae are known from the Cretaceous, including the living genera '' Attagenus'' and '' Megatoma.'' The ancestral ecology of the group was likely mycophagy, which is retained in Orphilinae, with the ancestor of most other lineages making the transition to saprophagy.
Ctesias
Ctesias ( ; ; ), also known as Ctesias of Cnidus, was a Greek physician and historian from the town of Cnidus in Caria, then part of the Achaemenid Empire.
Historical events
Ctesias, who lived in the fifth century BC, was physician to the Acha ...
Dermestes lardarius
''Dermestes lardarius'', commonly known as the ''larder beetle'' or ''moisture bug'', is a species of beetle in the family Dermestidae, the skin beetles. It is found worldwide.posterior end. The larva of the black larder beetle has less strongly curved appendages. Mature larvae of both species tend to bore into hard substrates such as wood, cork, and plaster to
pupa
A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...
te.Lyon, W. F Hide and Larder Beetles Ohio State University Extension Fact Sheet.
Larder beetles are infrequent household pests. . Pest Solutions Plus. Adults and larvae feed on raw skins and hides. Adult larder beetles are generally 1/3 to 3/8 of an inch long and are dark brown with a broad, pale yellow spotted band across the upper portion of the elytra. There are three black dots arranged in a triangle shape on each wing. The
sternum
The sternum (: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major bl ...
and legs of the larder beetle are covered in fine, yellow setae. Adult larder beetles are typically found outdoors in protected areas during the winter, but during the spring and early summer they enter buildings. Females lay approximately 135 eggs near a food source, and the eggs will hatch in about 12 days. The life cycle of larder beetles lasts around 40 to 50 days.
The black larder or incinerator beetle, '' Dermestes ater'', is completely dark with scattered yellow setae on the body. It is similar to '' Dermestes maculatus'' but lacks serrations on its elytra. Its ventral surface is yellow instead of white. This beetle is a pest of fish, mushrooms, and cheese.Genus Dermestes BugGuide.
Hide beetle (leather beetle)
'' Dermestes maculatus'', known as the hide beetle, leather beetle, or skin beetle, feeds on raw skins and hides like the larder beetle. This species is similar in appearance to the larder beetle, with larvae covered in short and long reddish brown or black setae, but its two spine-like posterior appendages curve forward. Also, in adults, the forewings are dark brown and the sternum is mostly white with some black. Its life cycle is 60 to 70 days and the female can lay up to 800 eggs.
The hide and larder beetles both feed on an assortment of animal protein based products and cause serious damage in the areas of silkworm production and museums.
Carpet beetle
Carpet beetle larvae start to feed as soon as they hatch. They are carrot shaped and heavily covered with setae, especially on their posterior end. The number of
instars
An instar (, from the Latin ''wikt:instar#Latin, īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each ecdysis, moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the ...
typically ranges from five to 11 and in some cases may reach as high as 20. Larvae of the black carpet beetle ''Attagenus megatoma'' may grow up to and be yellow to brown in color. Other types of carpet beetle are regularly long and covered with dark setae. Certain species have distinctive tufts of setae extending from their posterior end. These beetles are attracted to soiled fabrics and crevices where dead insects may serve as a food source.Lyon, William F Carpet Beetle Ohio State University Extension Fact Sheet. The larvae of the carpet beetle are often referred to as "woolly bears" or "buffalo moths".
Black carpet beetle
The black carpet beetle, ''Attagenus megatoma'', is a widely known stored product pest and one of the most destructive because of its potential damage to household products containing
keratin
Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. It is the key structural material making up Scale (anatomy), scales, hair, Nail (anatomy), nails, feathers, horn (anatomy), horns, claws, Hoof, hoove ...
, which is a protein found in animal hair and feathers. They are also able to burrow through various types of food packaging, allowing passage for other insects.
Females can lay up to 90 eggs and they hatch in about 8 to 15 days. Generally, this species only has one generation a year. The time it takes to become an adult varies from six months to a year. In addition, an adult black carpet beetle can live for an additional two months.Exploring California Insects: Carpet or Museum Beetles . The average adult size is about 2.8 to 5 mm long and they are oval, dark brown to shiny-black in color, and have brown legs.
Varied carpet beetle
The varied carpet beetle, ''Anthrenus verbasci'', attacks typical household objects. Carpet beetles are normally associated with things such as carpets, wool, furs, and any processed animal or plant food. Their appetite also includes dead insects, spiders, and even nectar and pollen. They are typically found throughout the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
and
Canada
Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
. Females can lay up to 40 eggs and the number of larval instars is seven or eight. The time it takes to become an adult varies from about eight months to a year. In addition, the adults can live around 2 to 6 weeks. This species varies in shape, size, color, and pattern of scales. On average, the adults are 2 to 3 mm in length and have scales that vary from white, brown, yellow, or even gray-yellow. The hairs of the larvae can cause allergic reactions such as contact dermatitis or blisters in humans who come into contact with the sharp tiny hairs.
Khapra beetle
On hatching, the larvae of khapra beetle (''Trogoderma granarium'') are around 1.6 to 1.8 mm long and mostly covered with dense setae, some simple and some barbed. Larvae are yellow-white but the head and body setae are brown. As the larvae further develop, their color changes to a golden or reddish brown and the abdomen portion becomes proportionally shorter. The mature larvae reach a maximum length of 6 mm long and 1.5 mm wide.Harris, D.L. (2006 Khapra Beetle University of Florida IFAS Extension.
The khapra beetle is a stored-product pest. Infestations are difficult to control because they crawl into cracks and crevices, remaining for long periods of time. They tend to infest grains and create serious losses to stored products. The adults are covered with setae and are approximately 1.5 to 3 mm long and 1 to 2 mm wide. Male khapra beetles are brown to black with reddish brown markings on the elytra. Females are slightly larger and are lighter in color. The short, 11 segmented antennae has a club of 3 to 5 segments, which fit into a groove on the side of the pronotum.
Control
Hide and larder beetles
Modern methods of meat slaughtering, storage, and distribution have reduced potential infestations of hide beetles. Proper housekeeping is crucial for the prevention of infestations. Dead insects in homes usually attract these beetles because they are a prime food source for hide and larder beetles. Food must be tightly sealed or stored in a refrigerator to avoid any beetle access. Freezing food for a week or heating meat in a pan or microwave for prolonged lengths can kill insects found in infested foods and prevent them from spreading.
Household fibers, such as wool and silk, are especially prone to moth damage and special cleaning, which includes moth proofing, needs to be done frequently. Application of
insecticides
Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, in ...
must be by spot treatment to crack and crevice sites where they are suspected of hiding.
Pyrethrin
The pyrethrins are a class of organic compounds normally derived from ''Chrysanthemum cinerariifolium'' that have potent Insecticide, insecticidal activity by targeting the nervous systems of insects. Pyrethrin naturally occurs in chrysanthemum f ...
s are labeled for use against hide beetles. Insecticides used for carpet beetles are also appropriate to use against hide and larder beetles.
Carpet beetles
Regular cleaning of spilled food or lint will eliminate any sites for potential breeding. Susceptible items like food, woolens, and furs should be stored in an insect-proof container. If an infestation is suspected then the source of the problem must be removed and destroyed to further limit any possibility of spreading. These beetles can be killed with extreme heat or exposure to freezers.Cranshaw, W.S. (2000) Carpet Beetles Colorado University State-Extension.
Pyrethroid
A pyrethroid is an organic compound similar to the natural pyrethrins, which are produced by the flowers of pyrethrums (''Chrysanthemum cinerariaefolium'' and ''Chrysanthemum coccineum, C. coccineum''). Pyrethroids are used as commercial and hou ...
insecticides can be used to control carpet beetles. These contain active ingredients such as
permethrin
Permethrin is a medication and an insecticide. As a medication, it is used to treat scabies and lice. It is applied to the skin as a cream or lotion. As an insecticide, it can be sprayed onto outer clothing or mosquito nets to kill the insects ...
, bifenthrin, deltamethrin and tralomethrin.
Diatomaceous earth#Pest control, Diatomaceous earth is also effective.
Image gallery
Image:Larder beetle grub.jpg, The grub of a larder beetle (''Dermestes lardarius'')
Image:Manduca quinquemaculata dermestidae damage sjh.JPG, Dermestidae damage to a ''Manduca quinquemaculata'' in an insect collection
Image:Woolly_bear.jpg, The larva of ''Anthrenus verbasci'' beetle
Image:grain_bait_wolly_bear.jpg, The larva of an ''Anthrenus verbasci'' beetle, frass, cast skin & a single grain of blue rodent bait damaged by the larva
Image:Sceliphron and pest.jpg, Carpet beetle damaging a ''Sceliphron destillatorius'' in an insect collection
References
Further reading
* John M. Kingsolver, "Dermestidae", in Ross H. Arnett Jr. and Michael C. Thomas, ''American Beetles'' (CRC Press, 2002), vol. 2.
*
*Pasquerault, T Vincent, B, Chauvet, B, Dourel, L, and Gaudry, E (2008). Répartition des espèces du genre Dermestes L. 1758 récoltés sur des cadavres humains (Coleoptera Dermestidae). ''L'entomologiste'' Tome 64 N°4 pp 221–224.
* Hinton, H.E., 1945 ''A monograph of the beetles associated with stored products''. 1, 387–395 British Museum (Natural History), London. Keys to world adults and larvae, genera and species; excellent figures, full species information.
* Freude, H.; Harde, K.W.; Lohse, G.A., 1979 ''Dermestidae''. ''Die Käfer Mitteleuropas'' 6: Diversicornia (Lycidae — Byrrhidae) 1206 text figs. 367pp. Goecke & Evers. Text in German; the Dermestidae are on pages 304–327.