CIIDAE Leach, 1819

Tree-Fungus Beetles

Includes several very common species, almost always associated with fungus but very difficult to identify.

Around the World

The Ciidae is a very large family of small beetles that are associated with the fruiting bodies of various fungi; around 650 species have been described and there are hundreds of specimens in museums etc. worldwide waiting to be named. The family is cosmopolitan and diverse even up to high latitudes but by far the greatest diversity, and where they are least understood and described, is in subtropical and tropical regions. About 50 species occur in Central Europe and 85 in the United States. They are sometimes referred to, and with some justification to the non-specialist, as nondescript, (Fowler refers to them as insignificant!) being mostly small, drab species not likely to be encountered away from trees and timber infested with fungi, but despite the overall superficial similarity of most species there is great diversity in the fine detail e.g. not many families of beetles display such a range in the number of antennal segments, even in a restricted fauna such as that of the U.K., and sexual dimorphism is common, sometimes extreme and often impressive. The smallest are around 0.5mm (some Octotemnus Mellié, 1847) while the largest reach 7mm (some Cis Latreille, 1796 and Xylographus Mellié, 1847) but the majority measure less than 3mm. Sexual dimorphism is displayed by most species; the males have tubercles or horns on the head and/or pronotum, the first abdominal tergite is usually modified, and the frontoclypeal ridge and anterior pronotal margin are often produced into straight or curved plates, good examples include the Neotropical Falcocis brasiliensis Lopes-Andrade, 2007, the Palaearctic Strigocis bicornis (Mellié, 1849) and the widespread invasive Neotropical native Cis bilamellatus Fowler, 1884. Sometimes the mandibles are exaggerated as in the Palaearctic Octotemnus mandibularis (Gyllenhal, 1813), and sometimes the dimorphism is extreme as in the Neotropical Cis taurus Reitter, 1878 or the Oriental Cis capricornis Kawanabe, 1997.

The family is divided somewhat unequally into two subfamilies; the Sphindociinae Lawrence, 1974 includes only a single species of Sphindocis Fall, 1917, S. denticollis Fall, 1917 which is native to the northern coastal regions of California and so far not recorded elsewhere. It is a pale, elongate  and  rather  flat  species with  11-segmented  antennae,  a feature

POLYPHAGA Emery, 1886 

TENEBRIONOIDEA Latreille, 1802











Cis boleti

Cis boleti

Octotemnus glabriculus

Octotemnus glabriculus

Sulcacis nitidus

Sulcacis nitidus

Orthocis alni

Orthocis alni

unique in the family, and was formerly included in the Tetratomidae but transferred to the present family on the basis of the distinct lacinar lobe of the larval maxilla-a ciid character not seen in other cucjiform groups. The larvae are known to bore into decaying wood below the fruiting bodies of the host fungus, Antrodia albida. The remaining species are included in three tribes of the Ciinae. The Orophini Thomson, 1863 comprises 5 genera including more than 20 species of the familiar Octotemnus and 11 species of Ropalodontus Mellié, 1847, both genera are widespread throughout the Holarctic, Oriental and Australasian regions but absent from the Neotropics and Africa south of the Sahara. The single species of Hyalocis Kawanabe, 1993, H. yakushimensis Kawanabe, 1993 is Oriental, Paratrichapus Scott, 1926 includes a single Seychelles endemic, P. sechellarum Scot, 1926, and the 30 or so species of Xylographus Mellié, 1847 occur throughout tropical regions. The Xylographellini includes two subtribes; the Xylographelina Kawanabe & Miyatake, 1996 includes two genera each with a single species, Scolytocis samoensis (Blair, 1928) from Samoa, and Xylographella punctata Miyatake, 1985 from Japan. The Syncosmetina Lopes-Andrade, 1996 includes two species of Syncosmetus Sharp, 1891 from Japan, and three species of Tropicus Scott, 1926 from islands in the Indian Ocean including Madagascar. The Ciini includes more than 30 genera and is cosmopolitan, the group is very likely to be split into further genera as e.g. the cosmopolitan genus Cis includes many species with 10-segmented antennae but are otherwise very diverse. Most genera are widely distributed but there are also some more localized groups e.g. Nipponapterocis Miytake, 1954 and Lipopterocis Miytake, 1954 occur only in Japan while Falsocis Pic, 1916, Porculus Lawrence, 1987, Phellinocis Lopes-Andrade & Lawrence, 2005 and Neoapterocis Lopes-Andrade, 2007 are Neotropical; Malacocis Gorham, 1886 is Neotropical and extends into the southern United States. There are several island endemic genera e.g. Apterocis Perkins, 1900 from Hawaii or Atlantocis Israelson, 1985 with 3 species from the Canary Islands, Azores and Madeira. Australasia, Madagascar and Africa have no described endemic genera but this is probably more to do with lack of research. Diphyllocis Reitter, 1885 includes a single species, D. opaculus (Reitter, 1878), which is endemic to Eastern Europe. Inevitably many species have been transported with the global trade in timber, perhaps the best documented is Cis bilamellatus Wood, 1884 which was introduced from Australia to the United Kingdom in the 19th century. Other widely distributed invasive species include Cis boleti (Scopoli, 1763), C. creberrimus Mellié, 1849, C. fuscipes Mellié, 1849 and Ceracis cucullatus (Mellié, 1849). Hadreule blaisdelli (Casey, 1900) is a pest of herbarium fungi and lichens in North America, and Cis chinensis Lawrence, 1991, which occurs in Europe, Asia and Brazil, is a pest of commercially produced dry fungi.


As with many groups members of the present family become familiar with a little experience, with a hand lens in the field they may be confused with small scolytids, especially as they are likely to be found in similar habitats, until the antennae are examined. Once familiar they become absolutely distinctive. 0.5-7mm. Mostly elongate, rather parallel and convex species although the unusual Syncosmetus japonicas Sharp, 1891 is an exception with separately rounded pronotum and elytra, and some are distinctly flattened. The majority are drab black to dark brown insects and bright colouration is rare but see Cis andersoni Lopes-Andrade, 2010, most are pubescent, albeit sometimes only very finely so, and this may be erect or decumbent and sometimes the setae are flattened and appear as scales. The head is declined but generally visible from above, the eyes entire, convex and usually protruding, with rather coarse facets which may bear fine setae in between. Vertex generally flat but often concave, and usually microsculptured and finely punctured, and sometimes with distinct fovea. Frontoclypeal suture distinct and strongly curved, the area anterior to this often modified in males, the labrum is free and always visible from in front, quadrate to elongate. Antennae 8-segmented in Octotemnus and some Ceracis Mellié, 1849 and Phellinocis Lopes-Andrade & Lawrence, 2005, otherwise 9- or 10-segmented. Antennal club generally 3-segmented and loose (a good character for recognizing the family) although with exceptions; in Scolytocis Blair, 1928 and Xylographella Miyatake, 1985 it is compact, and in several genera e.g. Cisarthron Reitter, 1885 and Cis there are species with a 2-segmented club. All U.K. species have a loose 3-segmented club. The club segments bear distinct rings of sensory setae at or near the apex, the number of which can be diagnostic for genera. The mandibles are broad, almost triangular, short and bidentate, and the apical segment of the palps cylindrical to conical although in the Xylographellini they are expanded and almost triangular. The pronotum is quadrate to distinctly transverse, rarely slightly elongate, and broadest at or behind the middle or towards the base, parallel, rounded or narrowed anteriorly, the base is about as broad as the base of the elytra. Lateral margin often distinctly bordered although this may not be complete, and sometimes explanate, the anterior angles variously developed and not always visible from above. The anterior margin is generally rounded and in the male often modified with horns or an extended transverse plate, in some species e.g. Ceracis cornifer (Mellié, 1849) the horn may be longer than the rest of the pronotum. The surface is generally strongly convex and variously punctured and microsculptured, without basal fovea but sometimes impressed by the anterior angles or behind the anterior margin, especially in males. The procoxal cavities are round to slightly transverse and vary from contiguous to widely separated, are variously open or closed, and the coxae protrude only weakly below the prosternum. Scutellum very variable; sometimes not visible, and sometimes raised at the apex or the base. Elytra quadrate to elongate, continuously rounded and completely covering the abdomen, in Orthocis Casey, 1898 and Strigocis Dury, 1917 they may diverge towards the apex. The humerus is variously developed and sometimes very strongly convex. The punctation is generally random and varies from very fine to coarse or a mixture of both; where present the coarse punctures may form indistinct striae but a scutellary stria is never present. Lateral margins bordered and sometimes explanate, the epipleura vary from broad and complete to narrow and present only towards the base. The surface is often roughly and randomly sculptured e.g. in Cis boleti (Scopoli, 1763) and, rarely, may be distinctly sculptured e.g. in Xylographella speciosa Lopes-Andrade, 2008 or with strongly raised longitudinal ridges and very strong punctation towards the apex as in Syncosmetus Sharp, 1891. Abdomen with 5 free ventrites; the first ventrite in the male has a modified area that is probably glandular and involved with pheromone secretion, only one species, Phellinocis romoaldoi Lopes-Andrade & Lawrence, 2005, is known to have a similar, albeit smaller, area in the female. (Similar modifications are seen on the first ventrite of some males in other groups e.g. Anthribidae, Bruchinae, Erotylidae and Tenebrionidae.) Mesocoxal cavities touching or only narrowly separated, and at least partly open laterally, mesocoxae round to slightly transverse and hardly projecting, the trocanters concealed. Metacoxae continuous or narrowly separated, transverse but not quite reaching the epipleura. The basal extension of the first ventrite is generally acute. Wings usually present and well-developed although macropterous or apterous forms do exist in some species. The legs are short and robust with the femora unarmed and usually not visible from above, the tibiae are short and expanded towards the apex; the tibial apices often provide good identification characters, especially the pro-tibiae which may be rounded, truncate or variously toothed or extended beyond the tarsal insertions. Tarsi 4-4-4 although they generally appear to be 3-3-3 or otherwise as the basal segments are often tiny and difficult to see; basal segments quadrate to transverse, the terminal segment often as long as the others combined. The claws are smooth and generally toothed at the base.


Ciids are associated with the fruiting bodies of a wide range of saproxylic fungi, mostly Polyporaceae but also Corticiaceae and others; they are not generally found on terrestrial forms as the fruiting bodies tend to be soft and short-lived. Adults may sometimes be found beneath bark without any obvious fungal association but this is not common and most species are rather specific regarding host choice although a few are more general, and many species of fungi have a specific ciid fauna associated with them. Many species are attracted to chemicals released when fruiting bodies are damaged or reach a certain stage of decay. Healthy fungi are often ignored and in many cases the beetles are attracted only after the fungal spores have been released and often when the fruiting bodies have died and begin to decompose. Many species choose older specimens in an advanced state of decay but, exceptionally, healthy bodies of e.g. Trametes or Laetiporus may host populations. Old birch polypores are always worth a look but in general any brackets should prove interesting. Adults are rarely seen outside the fungi, they bore into supporting tissue to oviposit and the entire life cycle is usually brief, often being completed within two months, and once colonized   many generations may develop, often with larvae, pupae and adults present simultaneously. Adults occur throughout the year and they sometimes continue breeding through the winter, in the spring very large populations may develop before other fungivores arrive. Some species are known to be parthenogenetic. Adults are active at night and are sometimes easy to spot by torchlight; some species will alight on freshly cut timber but in general they are not attracted to light, in warmer spells they may be seen walking on fungi and the surrounding timber and at this time tapping the fungi over a sheet will produce them. Taking samples for heat extraction is a very good way of surveying adults although this may be very destructive as huge numbers of some species may be found. Most species disperse nocturnally by flight but macropterous and apterous forms are sometimes found among leaf-litter or under bark on fallen timber, and it is not clear whether these are dispersing or breeding using micro fungi as hosts. Brackets are rich in carbohydrates and protein, and some metallic elements become concentrated in the tissues and so ciids are important recycling elements in the woodland ecosystem, many have evolved physiological and chemical defences to avoid the often toxic effects of fungal defence chemicals. Breeding ciids is usually simple as long as the fungi samples can be kept appropriately moist and many species are rather choosy about this; they can be kept in ventilated plastic containers and will happily breed for several generations so that over a summer a decent sized sample may produce large numbers of adults.

UK Species

The U.K. fauna includes 22 species in 7 genera and provide a good representation of the family. The tiny Octotemnus glabriculus (Gyllenhal, 1827) is distinctive in having 8-segmented antennae. It is common and widespread and likely to be among the first species to be found. Two genera, each with a single representative, have 9-segmented antennae; the dark, almost black, Sulcacis nitidus (Fabricius, 1792) and the pale brown Ennearthron cornutum (Gyllenhal, 1827) are both widely distributed but of local occurrence throughout England and Wales. Both display sexual dimorphism. The remainder have 10-segmented antennae. Two species are distinctive in being conspicuously pubescent and having strongly dilated pro-tibiae. The smaller, 1.2-1.4mm and dark Strigocis bicornis (Mellié, 1849) occurs in Southern England while the larger, 1.8-2.2mm and brown Rhopalodontus perforatus (Gyllenhal, 1813) is generally rare with records scattered through England and Scotland. Our two species of Orthocis Casey, 1898 are distinctly elongate, shiny black and regularly and randomly punctured; both are clothed with small scales which become obvious when illuminated from a certain direction. O. coluber (Abeille de Perrin, 1874) is a rare species occurring in central England while O. alni (Gyllenhal, 1813) is more widespread. Fifteen species of Cis occur in the U.K. Several are common and widespread and should soon be found e.g. C. boleti (Scopoli, 1763), C. fagi Waltl, 1839, C. hispidus (Paykull, 1798) and C. bilamellatus Wood, 1884 which is an established introduction from Australia and, along with Octotemnus, among our most common species. On the other hand some are very localized e.g. C. jacquemartii Mellié, 1849 and C. dentatus Mellié, 1849 occur only in the Scottish Highlands, and C. lineatocribratus Mellié, 1849 occurs in the Scottish Highlands as well as in the south of England. C. punctulatus Gyllenhal, 1827 is a very rare species with a few records scattered through England, Wales and Scotland. Most species exhibit at least some sexual dimorphism. The morphology of our species varies widely from large and flattened to small and almost cylindrical, the form of the pro-tibiae, pronotal margins and the punctation and pubescence offer good characters and specimens will only occasionally need to be dissected. Despite many name changes the older keys of Joy and Fowler still remain useful and there is plenty of information regarding host specificity and ecology etc. in the literature.

Ropalodontus perforatus

Strigocis bicornis

Orthocis alni

Orthocis coluber

Cis bilamellatus 1.jpg

Cis castaneus

Cis dentatus

Cis festivus

Cis submicans

Cis jacquemartii

Cis vestitus

Cis lineatocribratus 

Cis villosulus

Cis micans

Cis punctulatus

Ennearthron cornutum

Cis pygmaeus

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