Dermestidae

Dermestidae are a family of Coleoptera 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 scavengers that feed on dry animal or plant material, such as skin or pollen, animal hair, feathers, dead insects and natural fibers. Members of Dermestes are found in animal carcasses, while others may be found in mammal, bird, bee, or wasp nests. Thaumaglossa only lives in the egg cases of mantids, while Trogoderma species are pests of grain.
These beetles are significant in forensic entomology. Some species are associated with decaying carcasses, which may help with criminal investigations. Some species are pests and can cause extensive damage to natural fibers in homes and places of business.
They are used in taxidermy and by natural history museums to clean animal skeletons. Some dermestid species, commonly called "bow bugs", infest violin cases, feeding on the bow hair.

Description

Adult Dermestidae are generally small beetles, 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 and usually fit into a groove on the underside of the thorax, 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. In subfamily Megatominae and the genus Trinodes, some of these setae are hastisetae: barbed setae ending in spear-like heads. 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 of the last larval instar.

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, 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, nests and burrows of various animals.
Larvae of subfamilies Dermestinae and Attageninae, burrow into feeding substrates, pupate in concealed locations, and show fast escape behaviours when disturbed. Larvae of Megatominae, 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 and nectar. 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 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, both those attached to exuviae and those shed by larvae, cause health problems in humans when inhaled, ingested in contaminated food or touched with skin.

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 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:

Evolution

While possible members of the family have been described from the Late Triassic 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.

Taxonomy

According to World Dermestidae catalogue, following taxonomic division is proposed for Dermestidae :

Dermestidae
*Megatominae
**Anthrenini
**Megatomini
**Ctesiini
*Dermestinae
**Dermestini
**Marioutini
**Paradermestini
*Thorictinae
**Thorictini
**Thaumaphrastini
*Orphilinae
**Orphilini
**Ranolini
*Trinodinae
**Cretonodini
**Thylodriini
**Trichelodini
**Trinodini
**Trinoparvini
*Attageninae
**Attagenini
**Apphianini
**Adelaidiini
**Cretodermestini
**Eckfeldattagenini
**Egidyellini
*Trogoparvinae
Genera

Dermestidae contains the following 74 genera:

Adelaidella Zhou, Ślipiński & Liu, 2020
Adelaidia Blackburn, 1891
Afrothorictus Andreae, 1967
Amberoderma Háva & Prokop, 2004
Anthrenocerus Arrow, 1915
Anthrenus Geoffroy, 1762
Apphianus Beal, 2005
Apsectus LeConte, 1854
Araphonotos Beal & Kadej, 2008
Attagenus Latreille, 1802
Caccoleptoides Herrmann, Háva & Kadej, 2015
Caccoleptus Sharp, 1902
Chilattagenus Háva, 2021
Claviella Kalík, 1987
†Cretoattagenus Háva, 2020
†Cretodermestes Deng, Ślipiński, Ren & Pang, 2017
†Cretomegatoma Háva, 2021
†Cretonodes Kirejtshuk & Azar, 2009
Cryptorhopalum Guérin-Méneville, 1838
Ctesias Stephens, 1830
Dearthrus LeConte, 1861
Derbyana Lawrence & Ślipiński, 2005
Dermalius Háva, 2001
Dermeanthrenus Háva, 2008
Dermestes Linnaeus, 1758
†Eckfeldattagenus Háva & Wappler, 2014
Egidyella Reitter, 1899
Evorinea Beal, 1961
Globicornis Latreille, 1829
Hemirhopalum Sharp, 1902
Hexanodes Blair, 1941
Hirtomegatoma Pic, 1931
Jiriella Kitano, 2013
Katkaenus Háva, 2006
Labrocerus Sharp, 1885
Liberorphinus Háva & Matsumoto, 2021
Macrothorictus Andreae, 1967
Mariouta Pic, 1898
Megatoma Herbst, 1791
Miocryptorhopalum Pierce, 1960
Myrmeanthrenus Armstrong, 1945
Novelsis Casey, 1900
†Oisenodes Kirejtshuk, Háva & Nel, 2010
Orbeola Mulsant & Rey, 1868
Orphilus Erichson, 1846
Orphinus Motschulsky, 1858
Papuderma Háva, 2021
†Paradermestes Deng, Ślipiński, Ren & Pang, 2017
Paranovelsis Casey, 1900
Paratrogoderma Scott, 1926
Pecticaccoleptus Háva, 2004
Phradonoma Jacquelin du Val, 1859
Ranolus Blair, 1929
Reesa Beal, 1967
Rhopalosilpha Arrow, 1929
Sefrania Pic, 1899
Socotracornis Háva, 2013
Sodaliatoma Háva, 2013
Thaumaglossa Redtenbacher, 1867
Thorictodes Reitter, 1875
Thorictus Germar, 1834
Thylodrias Motschulsky, 1839
Trichelodes Carter, 1935
Trichodryas Lawrence & Ślipiński, 2005
Trinodes Dejean, 1821
Trinoparvus Háva, 2004
Trogoderma Dejean, 1821
Trogoparvus Háva, 2001
†Tuberphradonoma Háva, 2021
Turcicornis Háva, 2000
Valdesetosum Háva, 2015
Volvicornis Háva & Kalík, 2004
Zahradnikia Háva, 2013
Zhantievus Beal, 1992
Selected taxa

Larder beetles

The larva of the larder beetle Dermestes lardarius is longer than the adult and is covered in reddish brown or black setae. It has two back-curved, spine-like appendages on the 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 pupate.
Larder beetles are infrequent household pests. 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 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.