Dermestidae

Dermestidae are a family of Coleoptera that are commonly referred to as skin beetles. Other common names include larder beetle, hide or leather beetles, carpet beetles, and khapra beetles. There are over 1,100 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 helps with criminal investigations. Some species are pests ( urban entomology) and can cause extensive damage to natural fibers in homes and businesses.

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 (1-12 mm long), rounded to oval in shape, with hairy or scaly elytra that may form distinctive and colourful patterns.Byrd, Jason. Castner, James (2001)
Forensic Entomology: The Utility of Arthropods in Legal Investigations
/ref> 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, 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 (setae). 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 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 (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 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 ( rhinoconjunctivitis, asthma), ingested in contaminated food (nausea, fever, diarrhea, proctitis, perianal itching) or touched with skin (dermatitis).

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:

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)''

Selected taxa

Genera

These 42 genera belong to the family Dermestidae:

* '' Adelaidia'' Blackburn, 1891 ^g
* '' Amberoderma'' Háva & Prokop, 2004 ^g
* '' Anthrenocerus'' Arrow, 1915 ^g
* ''Anthrenus'' O. F. Müller, 1764 ^{i c g b} (carpet beetles)
* ''Apsectus'' LeConte, 1854 ^{i c g b}
* ''Attagenus'' Latreille, 1802 ^{i c g b} (black carpet beetles)
* '' Caccoleptoides'' Herrmann, Háva & Kadej, 2015 ^g
* ''Caccoleptus
* '' Cretonodes'' Kirejtshuk & Azar, 2009 ^g
* '' Cryptorhopalum'' Guérin-Méneville, 1838 ^{i c g b}
* ''Ctesias'' Stephens, 1830 ^{i c g b}
* '' Dearthrus'' LeConte, 1861 ^{i c g b}
* ''Dermestes'' Linnaeus, 1758 ^{i c g b}
* '' Egidyella'' Reitter, 1899 ^{i c g}
* ''Evorinea
* ''Globicornis'' Latreille, 1829 ^g
* '' Jiriella'' Kitano, 2013 ^g
* '' Labrocerus'' Sharp, 1885 ^{i c g}
* '' Megatoma'' Herbst, 1792 ^{i c g b}
* ''Miocryptorhopalum
* ''Neoanthrenus''
* '' Novelsis'' Casey, 1900 ^{i c g b}
* '' Oisenodes'' Kirejtshuk, Háva & Nel, 2010 ^g
* ''Orphilodes'' Lawrence & Ślipiński, 2005 ^g
* '' Orphilus'' Erichson, 1846 ^{i c g b}
* '' Orphinus'' Motschulsky, 1858 ^{i c g b}
* '' Paranovelsis'' ^b
* '' Phradonoma'' Jacquilin du Val, 1859 ^{g b}
* '' Pseudohadrotoma'' ^b
* '' Ranolus'' Blair, 1929
* ''Reesa'' Beal, 1967 ^{i c g b}
* '' Reeveana'' Tillyard, 1923 ^g
* ''Sefrania'' Pic, 1899 ^g
* ''Thaumaglossa'' Redtenbacher, 1867 ^{i c g b}
* ''Thorictodes'' Reitter, 1875 ^{i c g b}
* ''Thorictus'' Germar, 1834 ^g
* ''Thylodrias
* ''Trichodryas'' Lawrence & Slipinski, 2005 ^g
* ''Trinodes'' Dejean, 1821 ^g
* ''Trogoderma'' Dejean, 1821 ^{i c g b}
* '' Tryoniopsis'' Tillyard, 1923 ^g
* '' Zahradnikia'' Háva, 2013 ^g
* ''Zhantievus'' Beal, 1992 ^g

Data sources: i = ITIS, c = Catalogue of Life, g = GBIF, b = Bugguide.net

Larder beetles

The larva of the larder beetle ''Dermestes lardarius

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