Trogidae

Hide beetles
Trox sabulosus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Coleoptera
Superfamily:	Scarabaeoidea
Family:	Trogidae MacLeay, 1819
Genera
Afromorgus [subgenus of Omorgus?] Madagatrox Omorgus Polynoncus Trox
Diversity
c. 300 species

Trogidae or hide beetles are a family of beetles with a distinctive warty or bumpy appearance. Found worldwide, the family includes about 300 species contained in three or four genera.^[1]

Trogids range in length from 2.5 to 20.0 mm. Their shape is oblong to oval, with a generally flat abdomen. Their color ranges from brown to gray or black, and they often encrust their bodies with dirt. They resemble scarab beetles with heavy limbs and spurs.

They are scavengers and are among the last species to visit and feed on carrion. They are most often found on the dry remains of dead animals. Both adults and larvae will eat feathers, fur, and skin. Some species are found in bird and mammal nests. Details of the life histories of many species are poorly known, since many are specialized to particular types of nests. They are often overlooked by predators and collectors due to their behaviors of cover their body with dirt and becoming motionless when disturbed.

This group may also be considered Troginae, a subfamily of Scarabaeidae. The common name "skin beetle" is sometimes used in reference to these beetles, but more often refers to species of Dermestidae.

Origins

Hide beetles are found worldwide. More species of Trogidae are found in dry environments instead of moist environments; typically temperate plains areas. Each genus is more diverse in different regions of the world. Trox is found in the Holarctic/Ethiopian area; Omorgus within the southern continents; and Polynoncus is found in South America.^[2]

There is controversy over whether Trogidae it its own family or a subfamily of Scarabaeidae.^[2] One major reason for the dispute between classifications is the possible evolution of the ommatidium in the eyes. Different environmental pressures and predators may have led to the adaptation of ommatidium structures within this family. For example the more advanced and numerous the ommatidium the more present the larger the ability of the insect to escape and elude predators. Trogidae may have evolved in Australia.^[3]

Anatomy

Trogidae are characterized by their distinct dirt-encrusted, warty or bumpy appearance. They are usually brown, gray, or black in color and are covered with short, dense setae. Their body shape is oblong to oval with a flat abdomen and their length varies from 2 to 20 millimeters. The antenna of hide beetles are usually short and clubbed.^[4] The hardened elytra of Trogidae, which are generally covered with small knobs giving the beetle their rough appearance, meet along the midline of the body and cover the entire abdomen and well-developed wings. Their head is bent down and covered by the pronotum.^[5] They also have heavy limbs and spurs resembling those of scarab beetles. Trogidae larvae are a creamy yellow/white in color, except at their caudal end which darkens as it accumulates with feces. Their heads are dark and heavily sclerotized. The abdominal segments of hide beetles have at least one or more transverse rows of setae.^[6]

Diet and Habitat

Predators rarely attack species of Trogidae. They avoid detection and predation due to their dirt covering and motionless behavior. Birds will prey upon hide beetles that have invaded the bird nests.^[6]

Species of Trogidae often feed off of carcasses in the wild that have died and are decomposing. In one lab experiment done in 1998 by the Department of Zoology at the University of Melbourne, the hide beetle ate all tissues on a sheep carcass and left the bones. Along with carrion, hide beetles are found within the pellet of many animal species, on other decaying dry matter, and around birds’ and mammals’ nests and feathers as well as aging bones.

Mating Habits and Life Cycle

There is little known about the life cycle of the Trogidae specifically. Their life cycles are very similar to the other genera of Scarabaeoidea (i.e. Passalidae and Lucanidae). After impregnation of the female by the male, the female will lay the eggs and the larvae will hatch after an unknown amount of time. During decomposition of a carcass, the beetles will leave their nest to feed on the carrion. As the last succession of insects to appear on the carcass, both larvae and adults can be found feeding on the dry remains. At the site of the carcass, an impregnated female will dig small, vertical columns underneath the carcass to lay her eggs allowing the larvae to locate food after hatching. Trogidae usually have 3-5 instars.^[6]

Forensic Importance

The utility of Trogidae in forensic entomology is unknown at this time. Though they typically arrive last in the order of succession, they can be the first in succession on burned and charred bodies. After the burned skin is eaten away by the Trogids, the corpse (with now-exposed, "fresher" surfaces) allows for viable colonization by other forensically important insects that help determine accurate Post mortem interval estimates.^[7]

Various species of Trogidae have been used by museums to clean up skeletons by eating any remaining dried material left on the skeletons leaving them clean for display. This method of bone-stripping has been used by some museums for many years as it is the most effective method.^[8]

Current and Future Research

The Chinese Academy of Sciences funded a study on the classification of this family of beetles.^[9] The forensic importance of African Trogidae and other carrion-associated beetles is being studied at the University of Pretoria. This project is investigating how the presence of beetles on carrion affects the infestation of other arthropods in carrion in Africa.^[10]

Species

Omorgus

Omorgus acinus Scholtz, 1980 (Tanzania)

Omorgus alternans (MacLeay, 1827) (Australia)

Omorgus amitinus Kolbe, 1904 (Kenya)

Omorgus asper LeConte, 1854 (southern USA, Mexico)

Omorgus asperulatus Harold, 1872 (Southern Africa)

Omorgus australasiae (Erichson, 1842) (Australia)

Omorgus baccatus Gerstaecker, 1867 (Kenya, Tanzania)

Omorgus badeni (Harold, 1872) (Brazil, Colombia)

Omorgus batesi (Harold, 1872) (Argentina, Brazil)

Omorgus birmanicus Arrow, 1927 (Southeast Asia)

Omorgus borgognoi Marchand, 1902 (Mauretania, Mali, Chad)

Omorgus borrei (Harold, 1872) (Uruguay, Argentina)

Omorgus brucki Harold, 1872 (Australia)

Omorgus candezei Harold, 1872 (Argentina)

Omorgus capillaceus Scholtz, 1990 (Colombia)

Omorgus carinatus Loomis, 1922 (Southern USA to Mexico)

Omorgus ciliatus (Blanchard, 1846)

Omorgus consanguineus Peringuey, 1901 (DR Congo, Zimbabwe, Namibia)

Omorgus costatus (Wiedemann, 1823) (Australia to India and China)

Omorgus crotchi Harold, 1871 (Australia)

Omorgus denticulatus (Olivier, 1789) (Africa)

Omorgus desertorum Harold, 1872 (Madagascar, Egypt, Arabia)

Omorgus discedens Haaf, 1954 (Somalia, Tanzania)

Omorgus elevatus Harold, 1872 (Angola, Namibia)

Omorgus endroedyi Scholtz, 1979 (Namibia, Angola)

Omorgus expansus Arrow, 1900 (Somalia)

Omorgus eyrensis Blackburn, 1904 (Australia)

Omorgus foveolatus Boheman, 1860 (Madagascar, Namibia)

Omorgus freyi Haaf, 1954 (Southern Africa)

Omorgus fuliginosus Robinson, 1941 (Costa Rica to Texas)

Omorgus funestus Lansberge, 1886 (Angola)

Omorgus gemmatus (Olivier, 1789) (Africa, Arabia)

Omorgus glaber Scholtz, 1980 (Tanzania) (= Afromorgus lindemannae)

Omorgus granulatus (Herbst, 1783) (India, Sri Lanka)

Omorgus guttalis Haaf, 1954 (Africa)

Omorgus inclusus Walker, 1858 (Sri Lanka to China)

Omorgus indicus Harold, 1872 (India, Thailand, China)

Omorgus indigenus Scholtz, 1990 (Galapagos:Española Island)

Omorgus inflatus Loomis, 1922 (Arizona, Texas, Mexico)

Omorgus insignicollis Blackburn, 1896 (Australia)

Omorgus insignis Haaf, 1954 (Namibia, Angola)

Omorgus italicus Reiche, 1853 (Italy, India, China)

Omorgus litigiosus

Omorgus lobicollis Arrow, 1927 (southern Burma)

Omorgus loxus Vaurie, 1955 (Brazil to Mexico)

Omorgus lugubris Haaf, 1954 (Kenya, Tanzania)

Omorgus melancholicus (Fahraeus, 1857) (Madagascar, Africa)

Omorgus mentitor Blackburn, 1896 (Australia)

Omorgus mictlensis Deloya, 1995 (Mexico)

Omorgus mollis Arrow, 1927 (Indonesia, Malaysia)

Omorgus monachus (Herbst, 1790) (Mexico, Southern USA)

Omorgus mutabilis Haaf, 1954 (Africa)

Omorgus nanningensis Pittino, 2005 (China)

Omorgus niloticus Harold, 1872 (Africa)

Omorgus nocheles Scholtz, 1990 (Argentina)

Omorgus nodicollis Macleay, 1888 (Western Australia)

Omorgus nodosus (Robinson, 1940) (Texas)

Omorgus nomadicus Scholtz, 1980 (Saudi Arabia)

Omorgus obesus Scholtz, 1980 (Africa)

Omorgus omacanthus Harold, 1872 (India)

Omorgus pauliani Haaf, 1954 (Laos, Vietnam)

Omorgus persuberosus Vaurie, 1962 (South America)

Omorgus peruanus Erichson, 1847 (South America) (=Polynoncus peruanus)

Omorgus ponderosus Peringuey, 1901 (Africa)

Omorgus principalis Haaf, 1954 (Africa)

Omorgus procerus Harold, 1872 (Africa, Arabia)

Omorgus punctatus (Germar, 1824) (Mexico to Southern USA)

Omorgus quadridens

Omorgus radula (Erichson, 1843) (Africa)

Omorgus rodriguezae Deloya, 2005 (Mexico)

Omorgus rubricans (Robinson, 1946) (Texas, Mexico)

Omorgus rusticus Fahraeus, 1857 (Africa)

Omorgus scabrosus (Palisot de Beauvois, 1818) (Canada to southern USA)

Omorgus scutellaris (Say, 1823) (Southern USA to Mexico)

Omorgus senegalensis Scholtz, 1983 (Senegal)

Omorgus spatulatus Vaurie, 1962 (Argentina)

Omorgus squalidus (Africa, Madagascar, Saudi Arabia)

Omorgus squamosus

Omorgus stellatus

Omorgus subcarinatus (MacLeay, 1864) (Australia, New Guinea)

Omorgus suberosus (Fabricius, 1775) (Spain, southern USA to South America, Australia)

Omorgus tessellatus LeConte, 1854 (Mexico)

Omorgus testudo Arrow, 1927 (southern Burma)

Omorgus texanus LeConte, 1854 (Texas)

Omorgus tomentosus (Robinson, 1941) (Mexico)

Omorgus tuberosus Klug, 1855 (Africa)

Omorgus tytus (Robinson, 1941) (USA)

Omorgus umbonatus LeConte, 1854 (Texas)

Omorgus unguicularis Haaf, 1954 (Africa)

Omorgus varicosus (Erichson, 1843) (Angola)

Omorgus villosus

Omorgus wittei Haaf, 1955 (Africa)

Omorgus zumpti Haaf, 1957 (Africa)

Phoberus

Phoberus capensis (Scholtz)

Polynoncus

Polynoncus aeger (Guerin-Meneville, 1844) (South America)

Polynoncus aricensis (Gutierrez, 1950) (South America)

Polynoncus bifurcatus (Vaurie, 1962) (South America)

Polynoncus brasiliensis (Vaurie, 1962) (South America)

Polynoncus brevicollis (Eschscholtz, 1822) (South America)

Polynoncus bullatus (Curtis, 1845) (Chile, Argentina)

Polynoncus burmeisteri Pittino, 1987 (Argentina)

Polynoncus chilensis (Harold, 1872) (Chile, Argentina)

Polynoncus diffluens (Vaurie, 1962) (Chile)

Polynoncus ecuadorensis Vaurie, 1962 (Ecuador)

Polynoncus erugatus Scholtz, 1990 (Argentina)

Polynoncus galapagoensis (Van Dyke, 1953) (Galapagos Islands)

Polynoncus gemmifer (Blanchard, 1846) (South America)

Polynoncus gemmingeri (Harold, 1872) (Panama to Argentina)

Polynoncus gibberosus Scholtz, 1990 (Chile)

Polynoncus gordoni (Steiner, 1981) (Peru)

Polynoncus guttifer (Harold, 1868) (South America)

Polynoncus haafi Vaurie, 1962 (Argentina)

Polynoncus hemisphaericus (Burmeister, 1876) (Argentina, Chile)

Polynoncus juglans (Ratcliffe, 1978) (Brazil, Guyana)

Polynoncus longitarsis (Harold, 1872) (Argentina, Chile)

Polynoncus mirabilis Pittino, 1987 (Chile, Argentina)

Polynoncus neuquen (Vaurie, 1962) (Chile, Argentina)

Polynoncus parafurcatus (Pittino, 1987) (Argentina, Brazil)

Polynoncus patagonicus (Blanchard, 1846) (Argentina)

Polynoncus patriciae Pittino, 1987 (Argentina, Uruguay)

Polynoncus pedestris (Harold, 1872) (Argentina)

Polynoncus peruanus (Erichson, 1847) (South America)

Polynoncus pilularius (Germar, 1824) (South America)

Polynoncus sallei (Harold, 1872) (Madagascar?, Ecuador, Peru)

Polynoncus seymourensis (Mutchler, 1925) (Galapagos Islands)

Polynoncus tenebrosus (Harold, 1872) (Ecuador)

Trox

Trox acanthinus Harold, 1872 (Mexico)

Trox aculeatus Harold, 1872 (South Africa)

Trox aequalis Say, 1831 (Canada to Mexico)

Trox affinis Robinson, 1940 (USA)

Trox alatus Macleay, 1888 (Australia)

Trox alius Scholtz, 1986 (Western Australia)

Trox amictus Haaf, 1954 (Australia)

Trox antiquus Wickham, 1909 (fossil:oligocene, Florissant, USA)

Trox aphanocephalus Scholtz, 1986 (Australia)

Trox arcuatus Haaf, 1953 (South Africa)

Trox atrox LeConte, 1854 (USA)

Trox augustae Blackburn, 1892 (Australia)

Trox boucomonti Paulian, 1933 (China, Vietnam)

Trox braacki Scholtz, 1980 (South Africa)

Trox brahminus Pittino, 1985 (India to Vietnam)

Trox brincki Haaf, 1958 (Lesotho)

Trox cadaverinus Illiger, 1801 (Europe to China)

Trox caffer Harold, 1872 (South Africa)

Trox cambeforti Pittino, 1985 (China)

Trox cambodjanus Pittino, 1985 (Cambodia, Laos)

Trox candidus Harold, 1872 (Australia)

Trox capensis Scholtz, 1979 (South Africa)

Trox capillaris Say, 1823 (Canada to southern USA)

Trox carinicollis Scholtz, 1986 (Western Australia)

Trox ciliatus Blanchard, 1846 (Argentina, Bolivia)

Trox clathratus (Reiche, 1861) (Corsica)

Trox conjunctus Petrovitz, 1975 (China)

Trox consimilis Haaf, 1953 (Southern Africa)

Trox contractus Robinson, 1940 (Texas)

Trox coracinus Gmelin, 1788 (unknown distribution)

Trox cotodognanensis Compte, 1986 (Spain)

Trox cribrum Gené, 1836 (France, Sardinia)

Trox cricetulus Ádám, 1994 (Croatia, Spain)

Trox curvipes Harold, 1872 (Australia)

Trox cyrtus Haaf, 1953 (South Africa)

Trox demarzi Haaf, 1958 (Australia)

Trox dhaulagiri Paulus, 1972 (Nepal)

Trox dilaticollis Macleay, 1888 (Australia)

Trox dohrni Harold, 1871 (Western Australia)

Trox doiinthanonensis Masumoto, 1996 (Thailand)

Trox elderi Blackburn, 1892 (South Australia)

Trox elongatus Haaf, 1954 (Northern Australia)

Trox erinaceus LeConte, 1854 (South Carolina)

Trox euclensis Blackburn, 1892 (Australia)

Trox eversmanni Krynicky, 1832 (Central Europe to Siberia)

Trox fabricii Reiche, 1853 (Spain, Sicily to Northern Africa)

Trox fascicularis Wiedemann, 1821 (Southern Africa)

Trox fascifer LeConte, 1854 (California)

Trox floridanus Howden & Vaurie, 1957 (Florida)

Trox formosanus Nomura, 1973 (Taiwan)

Trox foveicollis Harold, 1857 (USA)

Trox frontera Vaurie, 1955 (Texas)

Trox gansuensis Ren, 2003 (China)

Trox gemmulatus Horn, 1874 (California)

Trox gigas Harold, 1872 (Australia)

Trox gonoderus Fairmaire, 1901 (Madagascar)

Trox granuliceps Haaf, 1954 (Australia)

Trox granulipennis Fairmaire, 1852 (Northern Africa to Spain and Middle East)

Trox gunki Scholtz, 1980 (South Africa)

Trox hamatus Robinson, 1940 (USA)

Trox hispidus (Pontoppidan, 1763) (Europe)

Trox horridus Fabricius, 1775 (South Africa)

Trox howdenorum Scholtz, 1986 (Western Australia)

Trox howelli Howden & Vaurie, 1957 (Florida, Texas)

Trox ineptus Balthasar, 1931 (Transbaikal)

Trox insularis Chevrolat, 1864 (Southern USA, Cuba)

Trox kerleyi Masumoto, 1996 (Thailand)

Trox kiuchii Masumoto, 1996 (Thailand)

Trox klapperichi Pittino, 1983 (Turkey to Saudi Arabia, Middle East)

Trox kyotensis Ochi & Kawahara, 2000 (Japan)

Trox lama Pittino, 1985 (Tibet)

Trox laticollis LeConte, 1854 (New York)

Trox leonardii Pittino, 1983 (Spain to North Africa, Israel)

Trox levis Haaf, 1953 (South Africa)

Trox litoralis Pittino, 1991 (South Europe: Italy to Greece)

Trox luridus Fabricius, 1781 (Southern Africa)

Trox lutosus Marsham, 1802 (Great Britain)

Trox mandli Balthasar, 1931 (Transbaikal)

Trox mariae Scholtz, 1986 (Western Australia)

Trox mariettae Scholtz, 1986 (North Australia)

Trox marshalli Haaf, 1957 (Australia)

Trox martini (Reitter, 1892) (North Africa)

Trox matsudai Ochi & Hori, 1999 (Japan)

Trox maurus Herbst, 1790 (unknown distribution)

Trox montanus Kolbe, 1891 (Africa)

Trox monteithi Scholtz, 1986 (Australia)

Trox morticinii Pallas, 1781 (Central Asia)

Trox mutsuensis Nomura, 1937 (Japan)

Trox nama Kolbe, 1908 (Southern Africa)

Trox nanniscus Peringuey, 1901 (South Africa)

Trox nasutus Harold, 1872 (South Africa)

Trox natalensis Haaf, 1954 (South Africa)

Trox necopinus Scholtz, 1986 (Zambia)

Trox niger Rossi, 1792

Trox nigrociliatus Kolbe, 1904 (Ethiopia)

Trox nigroscobinus Scholtz, 1986 (Western Australia)

Trox niponensis Lewis, 1895 (Japan)

Trox nodulosus Harold, 1872 (Sardinia, Corsica)

Trox nohirai Nakane, 1954 (Japan)

Trox novaecaledoniae Balthasar, 1966 (New Caledonia)

Trox opacotuberculatus Motschulsky, 1860 (Japan, Taiwan)

Trox oustaleti Scudder, 1879 (fossil: eocene; Nine-mile Creek, British Columbia)

Trox ovalis Haaf, 1957 (North Australia)

Trox pampeanus Burmeister, 1876 (Argentina)

Trox parvicollis Scholtz, 1986 (North Australia)

Trox pastillarius Blanchard, 1846 (South America)

Trox pellosomus Scholtz, 1986 (Australia)

Trox penicillatus Fahraeus, 1857 (South Africa)

Trox perhispidus Blackburn, 1904 (Australia)

Trox perlatus Geoffroy, 1762 (Great Britain to Spain and Italy)

Trox perrieri Fairmaire, 1899 (Madagascar)

Trox perrisii Fairmaire, 1868 (Europe, North Africa)

Trox placosalinus Ren, 2003 (China)

Trox planicollis Haaf, 1953 (Southern Africa)

Trox plicatus Robinson, 1940 (Southern USA)

Trox poringensis Ochi, Kon & Kawahara, 2005 (Borneo, Java)

Trox puncticollis Haaf, 1953 (Saudi Arabia)

Trox pusillus Peringuey, 1908 (Africa)

Trox quadridens Blackburn, 1892 (Australia)

Trox quadrimaculatus Ballion, 1870 (Turkestan)

Trox quadrinodosus Haaf, 1954 (Australia)

Trox regalis Haaf, 1954 (Australia)

Trox rhyparoides (Harold, 1872) (Africa)

Trox rimulosus Haaf, 1957 (India)

Trox robinsoni Vaurie, 1955 (Canada to Texas)

Trox rotundulus Haaf, 1957 (Australia)

Trox rudebecki Haaf, 1958 (South Africa)

Trox sabulosus (Linnaeus, 1758) (Great Britain to Siberia)

Trox salebrosus Macleay, 1872 (Australia)

Trox scaber (Linnaeus, 1767) (Holarctic, North Africa, South America, Australia)

Trox semicostatus Macleay, 1872 (Australia)

Trox setifer Waterhouse, 1875 (Japan)

Trox setosipennis Blackburn, 1904 (Australia)

Trox sonorae LeConte, 1854 (Canada to New Mexico)

Trox sordidatus Balthasar, 1936 (Southeastern Europe)

Trox sordidus LeConte, 1854 (Canada to Texas)

Trox spinulosus Robinson, 1940 (USA)

Trox squamiger Roth, 1851 (Africa, Arabia)

Trox squamosus Macleay, 1872 (Australia, New Guinea)

Trox stellatus Harold, 1872 (Western Australia)

Trox strandi Balthasar, 1936 (Algeria)

Trox striatus Melsheimer, 1846 (USA)

Trox strigosus Haaf, 1953 (South Africa)

Trox strzeleckensis Blackburn, 1895 (Australia)

Trox sugayai Masumoto & Kiuchi, 1995 (Japan)

Trox sulcatus Thunberg, 1787 (Southern Africa)

Trox taiwanus Masumoto, Ochi & Li, 2005 (Taiwan)

Trox talpa Fahraeus, 1857 (South Africa)

Trox tasmanicus Blackburn, 1904 (Tasmania)

Trox tatei Blackburn, 1892 (Australia)

Trox terrestris Say, 1825 (USA)

Trox tibialis Masumoto, Ochi & Li, 2005 (Taiwan)

Trox torpidus Harold, 1872 (Central America)

Trox transversus Reiche, 1856 (Greece, Syria, Turkey)

Trox trilobus Haaf, 1954 (Australia, New Guinea)

Trox tuberculatus (De Geer, 1774) (USA)

Trox uenoi Nomura, 1961 (Japan)

Trox unistriatus Palisot de Beauvois, 1818 (Canada to Texas)

Trox variolatus Melsheimer, 1846 (Canada to Mexico)

Trox villosus Haaf, 1954 (Australia)

Trox yamayai Nakane, 1983 (Japan)

Trox yangi Masumoto, Ochi & Li, 2005 (Taiwan)

Trox zoufali Balthasar, 1931 (Taiwan)

References

External links

Wikispecies has information related to: Trogidae

Wikimedia Commons has media related to Trogidae.

• World Trogidae Directory Naked list and picture by coleopterist Shinya Kawai
• Guide to New World Scarab Beetles - Trogidae from University of Nebraska State Museum - Division of Entomology
• http://bugguide.net/node/view/5824
• http://www.ento.csiro.au/education/insects/coleoptera_families/trogidae.html
• Key to the British species of family Trogidae