CLERIDAE Latreille, 1802
Suborder: POLYPHAGA Emery, 1886
Superfamily: CLEROIDEA Latreille, 1802
Only poorly represented in the UK, many of our fourteen species are rare or only occasionally recorded as accidental specimens arrive from the continent.
Around the World
A large family of around 3600 described species included in 12 subfamilies although there are other systems where only 7 subfamilies are included and the group is under revision. Of these the Clerinae contains nearly half the species and the majority occur in Afrotropical regions. The family has a worldwide distribution with most species in the tropical regions. There are around 500 species in the U.S.A. and around 50 in Canada. In Europe there are around 110 species of which almost half are in the genus Trichodes Herbst, 1792. The U.K. fauna is represented by 14 species included in 10 genera and 5 subfamilies. The family Thaneroclerinae Chaplin, 1924, of which we have a single species, Thaneroclerus buqueti (Lefebvre, 1835), is listed as a subfamily of Cleridae in some systems.
Clerids are characteristic and soon recognized, especially within the limits of the European fauna. They are mostly near parallel and elongate or elongate-oval in appearance and range from 3-24mm. The upper surface is usually brightly coloured and patterned with red, orange, yellow or blue. The entire body is pubescent and often has erect setae on the dorsal surface. Most have clubbed antennae but in some they are serrate, gradually expanded towards the apex or moniliform. The eyes are usually visible from above and weakly to strongly emarginate, and the mandibles lack a basal tooth. The pronotum is generally cylindrical, narrower than the elytra and sometimes also narrower than the head, the lateral margins are absent in Tillinae, Hydnocerinae and Clerinae, otherwise present although not always for the entire length. The elytra usually have punctured striae; generally 10 rows except in Korynetes which have 12-14. Entire and rarely (eg. in the Australian Tenerus Spp.) exposing more than 2 tergites. Six visible sternites. Tarsi 5,5,5 with some segments bilobed, generally 2-4 but always the third. Fourth segment small so that some species appear tetramerous. Thaneroclerus difers here in that the mid and hind tarsi are slender and the front tarsi are compact with segments 1-4 dilated. Tibiae usually with one or two apical spines. Claws simple or toothed. Empodium bisetose. Clerids never have the eversible vesicles seen on the pronotum and abdomen of Malachids.
The group has developed a very wide range of feeding habits. Many species, including the brightly coloured Trichodes Herbst, 1792, but also the more drab Tilloidea Laporte, 1833, visit flowers where they predate grasshoppers and wasps etc. while the larvae feed on pollen. They generally occur in moist and sunny environments with abundant flowering plants. Tree living species e.g. Tillus Olivier, 1790, Tilloidea Laporte, 1833, Opilo Latreille, 1802 and Thanasimus Latrielle, 1806 generally feed both as adults and larvae on insects both within the wood and on the surface. The primary prey are Ptinids and Scolytids. Adult Clerids generally feed on other beetles while the larvae feed on other larvae, wandering the galleries to do so. Some larvae are voracious feeders able to consume several times their own body weight daily. Because of their predacious nature and large appetites, some species have been used as biological control agents; Thanasimus species are attracted to aggregation pheromones sprayed onto infested trees. Another group of tree living species do not enter the wood but feed in hymenopteran nests either on bee or wasp larvae, or as scavengers feeding on dead dry insects. In the tropics they also enter termite nests and one species is a specialist feeder on orthopteran egg masses. Species of Necrobia Olivier, 1795 are known as ham beetles; they are attracted to dry carrion, bones and skin as well as to meat products. Necrobia rufipes (DeGeer, 1775) is the red legged ham beetle, an important stored product pest (although much more so formerly) infesting stored dried or smoked meats. Adults feed on the surface while the larvae bore into fatty parts. Some species are synanthropic; Thaneroclerus Lefebvre, 1838, Opilo Latreille, 1802, Korynetes herbst, 1792 and Necrobia Olivier, 1795 all feed on stored products, Ptinids, insect debris and house longhorn larvae etc. Necrobia rufipes has been recorded feeding on a wide range of stored products from dried figs to Egyptian mummies, and stored wool and silk can also become infested. Clerid larvae are elongate, narrow and often depressed in arboreal species. They are often pink or yellow with dark head, pronotum and terminal abdominal segments. Abdominal segment nine bears paired urogomphi. The mouthparts are strongly protracted ventrally.
A key to the British species can be found HERE.
Good general introduction to the Western Palaearctic fauna. Includes keys and colour photographs.
A Practical Handbook of British Beetles
Norman H. Joy
Remains valuable, keys specimens to family and species level.
Brilliant introduction to the family.
Networking site covering many regions.
Icones Insectorum - Cleroidea
Guide to all the Central European Cleridae species.