Dermestidae | UK | Ukbeetles

DERMESTIDAE Latreille, 1804

Larder Beetles

Includes several common species, occurring indoors as pests and outside on timber and flowers. All too abundant, Anthrenus verbasci is a notorious destroyer of insect collections.

Introduction

This large family includes about 1400 species and is cosmopolitan, diversity increases towards the tropics although as many species are synanthropic, occurring in stored foodstuffs etc., the range of many is either increasing or has become cosmopolitan; about 130 species occur in North America and less than 100 in Europe, the U.K. list includes about 40 species in 13 genera and 6 subfamilies but others have occasionally been recorded in imported materials. There have been many changes in the classification but 6 subfamilies including 14 tribes seems to be an accepted modern system; two groups formerly given subfamily status have now been assimilated; the Marioutinae is now a tribe within the Dermestinae, and the Thylodriadinae is now a tribe within the Trinodinae. A modern system is classified as follows, with an emphasis on the European species.

Dermestinae Latreille, 1807 includes 2 tribes; Dermestini Latreille, 1807 includes about 90 species of the cosmopolitan genus Dermestes Linnaeus, 1758, and Marioutini Jacobson, 1913 with 2 genera and 3 species which do not occur in Europe.
Thorictinae Agassiz, 1846 includes 2 tribes; Thaumaphrastini Anderson, 1949 with 5 species of the cosmopolitan genus Thorictodes Reitter, 1875, and Thorictini Agassiz, 1846 with about 140 species of the cosmopolitan genus Thorictus Germar, 1834.
Orphilinae LeConte, 1861 includes the single tribe Orphilini LeConte, 1861 with 6 species of the Holarctic genus Orphilus Erichson, 1846.
Trinodinae Casey, 1900 includes 4 tribes:
- Trinodini Casey, 1900 includes 14 species of the cosmopolitan genus Trinodes Dejean, 1821. The genus was formerly included in the Cantharidae.
- Thylodriini Beal, 1959 includes the genus Thylodrias Motschulsky, 1839 with a single cosmopolitan species, T. contractus Motschulsky, 1839.
- Trichelodini Peacock, 1978 includes 2 species of Trichelodes Carter, 1935, formerly included in the Dascillidae.
- Trinoparvini Háva, 2010 includes 2 species of Trinoparvus Háva, 2004 from Madagascar and New Caledonia.
Attageninae Casey, 1900 includes 3 tribes:
- Attagenini Casey, 1900 includes about 190 species of the cosmopolitan genus Attagenus Latreille, 1802, and a single species of Sefriana Pic, 1899; S. bleusei Pic, 1899, a native North African species also recorded from Europe.
- Egidyellini Semenov-Tian-Shabskiy, 1916 includes only the genus Egidyella Reitter, 1899 with 2 species from Asia and California.
- Ranolini Háva, 2014 includes 2 genera from Asia and Australia; Orphilodes Lawerance & Slipinski, 2005 with 3 species, and Ranolus Blair, 1929 with 2 species.

POLYPHAGA Emery, 1886

BOSTRICHOIDEA Latreille, 1802

1.5-11mm

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Megatominae Leach, 1815 includes 2 tribes:
- Anthrenini Casey, 1900 includes about 240 species in 10 subgenera of the cosmopolitan genus Anthrenus Geoffroy, 1762.
- Megatomini Ganglbauer, 1904 is a large and cosmopolitan tribe of more than 25 genera. European genera include the widespread Palaearctic Globicornis Latreille, 1829 with 5 subgenera and about 25 species, Phradonoma du Val, 1859 with about 40 Palaearctic and African species of which 2 occur in Europe, the Holarctic Megatoma Herbst, 1782 with 24 species of which 2 are known from Europe, Ctesias Stephens, 1830 with 23 Afrotropical and Holarctic species and a single European representative, and Trogaderma Dejean, 1821 which is a cosmopolitan genus of about 140 species of which about 10 occur in Europe. The genus Antherocerus Arrow, 1915 contains about 30 Australasian species, one of which now occurs in Europe from imported foodstuffs. The native Nearctic genus Reesa Beal, 1967 contains a single species which now occurs in Europe and is spreading worldwide with trade.

Description

The majority of species are small, <10mm in length and drab coloured, in the Palaearctic region only species of Dermestes exceed this size, being up to 15mm. Most are elongate-oval and pubescent, usually densely so and often with setae of different lengths or, in Anthrenus species, with scales which often form patterns which may be useful in identification work. The head is usually at least to some extent deflexed and, with the exception of the Dermestinae and the Thorictinae, has a single ocellus placed centrally on the vertex. The mouthparts are usually well developed. The eyes are generally convex, often strongly so and protruding, and, with the exception of Anthrenus in which they are notched or at least sinuate along the anterior margin, entire and more or less circular. The antennae are 11-15 segmented and often clubbed or with strongly transverse segments, and with the terminal segment enlarged. The pronotum varies in shape but is usually convex with the lateral margin curved and narrowed anteriorly and the basal margin almost always strongly sinuate. The scutellum is generally distinct. With the exception of Thylodrias in which the male elytra are reduced and the female elytra vestigial, the elytra generally cover the abdomen and lack striae although a variously developed sutural stria is often present, usually randomly punctured and pubescent, in Trinodes the pubescence is very well developed. In some groups they are distinctly patterned e.g. Reesa, Trogoderma, and Megatoma. The wings are usually well developed and most species fly well. The abdomen has 5 visible sternites. The legs are mostly relatively long and narrow, the tibiae without lateral teeth and lacking, or with only weakly developed, terminal spurs. Tarsi 5-5-5 and usually with thin and elongate segments. In most species sexual dimorphism is obvious; the antennae of the males are usually more developed. Dermestid larvae are brown to black and densely pubescent, usually with setae of differing lengths and density, and with usually prominent urogomphi. Typically they occur among stored products or detritus in wild situations, they often consume dry animal materials that are difficult for other species to digest e.g. skins, wood, natural fibres and dried foodstuffs. They are photophobic, and some are used to clean skeletons in museums. In forensics they are often found in corpses during the dry and skeletal phase of decomposition and may be useful in assigning a time of death.

Ecology

Many dermestids are important pests in houses, food stores, warehouses and museums etc. They tend to be prolific breeders, very resilient, and can develop in a very wide range of materials, generally those of animal origin; meat and meat products, bones, feathers and fur but also on high protein plant material such as seeds and flours. Many species occur in the wild and here some are specialized feeders among spider webs, humble bee, solitary bee and wasp nests. Some may be found among the detritus in mammal and avian nests, or under bark on deciduous trees where they feed upon dead insects or cast larval skins etc. In bright sun some will appear on dead trees, logs and fence posts etc e.g. Megatoma and Trinodes. Sampling umbels and other flowers in hot weather is a good method to find some species, especially Anthrenus, and many are nocturnal, occurring on dead trees and logs e.g. Ctesias, and many species come to u.v. light. Many may be collected by pulling apart recently vacated nests or by taking samples of cobwebby bark for extraction and by setting malaise or other interception traps. Adults of many species may be found at windows or among accumulated dead insects in lighting boxes and fittings. In both domestic and commercial premises the adults can be carefully searched for in places where suitable host material is stored, especially so if adults are chanced upon on walls or at windows although it is not always easy to find the source of an infestation. Baited traps used indoors can be a good source of Dermestes and Reesa.