MYCETOPHAGIDAE Leach, 1815
Hairy Fungus Beetles
Several common species will be found associated with fungi. All species are nocturnal, and will generally be found in large numbers.
Around the World
This is a small family of about 200 species included in more than 20 genera, the classification is not settled but is dealt with in some detail, along with a key to world genera, by Lawrence, J.F. et.al in Zootaxa 2014, June 27, 195-229, which provides some interesting changes to the system, e.g. the genus Rhipidonyx Reitter, 1876 is transferred to the Tenebrionidae, as well as fascinating reading. Thus for now we ignore any higher-order classification and deal with the group mostly at the generic level. As always the biogeography is interesting; the family is dominated by two large genera; Mycetophagus Hellwig in Schneider, 1792, with more than 40 species, is mostly Holarctic, and Litargus Erichson, 1846, with about 45 species, is almost cosmopolitan with endemic species in Sumatra, Madagascar and Borneo etc. The usual kind of generic distribution is seen; Berginus Erichson, 1846 is Holarctic but is likely to spread due to the apparent expansion of the European B. tamarisci Wollaston, 1854 which was first recorded in the U.K. in 2008. The Nearctic fauna includes 26 species in 5 genera two of which, Lendomus Casey, 1924 and Thrimolus Casey, 1916, are endemic. Among Neotropical endemics are Caserus Dajoz, 1969 from Brazil, Catopius Sharp, 1902 from Central America, Felicivora Leschen & Lawrence, 1991 from Chile, and Pseudochrodes Reitter in Harold, 1876 from Chile and Brazil. Species of Escarus Reiche, 1864 occur in Europe and North Africa while the wider Palaearctic fauna is the most diverse of the family with many widespread species confined to the region e.g. Litargops Reitter, 1879 and Triphyllopsis Nikitsky, 1989. The widespread genus Pseudotriphyllus Reitter, 1879 includes 7 Palaearctic species and also extends to North Africa. Triphyllus Dejean, 1821 is a very widespread Palaearctic genus extending into Southeast Asia and with endemics in Madagascar and New Zealand. The monotypic Triphyllioides Miyatake, 1959 is endemic to Japan. Typhaea Stephens, 1829 is a small genus which is native to the Palaearctic and Southeast Asia but is now cosmopolitan due to the invasive pest species T. stercorea (Linnaeus, 1758) which is a mould-feeder associated with a range of stored products such as grains, tobacco and nuts etc. and continues to be recorded worldwide. The Australian fauna includes about 10 species in 7 genera. About 30 species are known from Europe of which 17 occur in Germany and 15 are included in the U.K. list although two of these, Litargus balteatus LeConte, 1856, added from a single nineteenth century record,
POLYPHAGA Emery, 1886
TENEBRIONOIDEA Latreille, 1802
and Mycetophagus fulvicollis Fabricius, 1793, with several nineteenth century records from a single Perthshire locality, are presumed to be extinct here, while Eulagius filicornis (Reitter, 1887) was added in 1996 from specimens discovered in Reading, having since become widespread, and Typhaea haagi Reitter, 1874 was added in 2012, probably introduced from North America it occurs among stored products. The European fauna has been in decline in recent decades, as is often the case with saproxylic groups, the majority of species are variously listed as infrequent or rare and at least half are on red-lists in many countries including the U.K. Of particular concern in Europe are Mycetophagus ater (Reitter, 1879), M. decempunctatus Fabricius, 1801, M. fulvicollis Fabricius, 1793 and M. populi Fabricius, 1798. Litargus balteatus LeConte, 1856 is only doubtfully recorded in many countries, including the U.K. With the exception of the U.K. Pseudotriphyllus suturalis (Fabricius, 1801) is extremely rare throughout with no recent records in many countries. Many species are infrequently recorded and prefer old established forest areas with plenty of dead wood and fungus, and many are quite specific in their choice of hosts etc.
All members of the family are small, 1.5-6.5mm. elongate to oval and moderately depressed beetles and the majority are distinctly pubescent. Most of the species are drab, some shade of brown to black, but many are have distinctive pale yellow to red markings to the elytra which make them easy to identify, at least to the genus. Historically the family has been placed within the Clavicornia, usually near the Dermestidae, but is now included in the Tenebrioniodea, a group in which most families have a 5-5-4 tarsal formula; in the present family it is 4-4-4 in the female and 3-4-4 in the male, some Colydiidae have the same tarsal formula but are distinguished by the mes-epimera not reaching the meso-coxal cavities as it does in the Mycetophagidae. Superficially they might be confused with some Tetratomidae, Biphyllidae or smaller Melandryids but the tarsi are distinctive. The family may be distinguished among the U.K. fauna by the following features; tarsi without bilobed segments, antennae always 11-segmented; moniliform to gradually thickened or with a 2-5 segmented club, the insertions not hidden beneath an expanded lateral margin of the frons. The head is transverse, broadest across large eyes and retracted into the prothorax so the temples are generally not visible, never deflexed and always visible from above. The palps are much shorter than the antennae and only rarely securiform, the mandibles are curved, not produced forward and bifid. Pronotum usually transverse, only rarely quadrate, with the lateral margins curved, narrowly explanate and usually smooth although in some finely crenulate but never with tubercles or callosities, the surface is smooth i.e. without sculpture, raised lines or carinae but in many there are two simple basal fovea. The elytra completely cover the abdomen and in many there are well-defined punctured striae, sometimes with raised lines in between. The ventral surface is more-or-less flat, contrasting with the dorsal surface, and there are 5 free abdominal sternites. The legs are moderately long with short femora which are generally visible from above, and long, straight tibiae which are only slightly thickened towards the apex, have small spines on the inner apical angle and lack lateral teeth. The tarsi are usually a little shorter than the tibiae and have the last segment shorter than the rest combined, and the claws are simple; not abruptly bent or toothed. The dorsal surface is usually clothed with short and fine pubescence but in some Mycetophagus there are scattered larger setae and in Typhaea the setae form distinct longitudinal rows. The hind wings are usually well-developed but some groups are macropterous or apterous. The small subfamily Escarinae Reitter, 1882, which includes 2 European genera but does not extend to the U.K., are distinct in having the meta-coxae barely reaching half way to the elytral margin and a short metasternum, in other groups the meta-coxae almost reach the elytral margin and the metasternum is much longer.
Mycetophagid larvae are elongate and sub-cylindrical, yellow to brown, smooth, and generally covered in simple hairs. The head and various sclerites are well-sclerotized and the mandibles robust and asymmetrical, the legs relatively long and usually have spine-like setae along their length. The ninth abdominal segment almost always has a pair of spine-like urogomphi that are directed posteriorly or weakly upturned, and the spiracles are annular and located within the membrane rather than on sclerites.
Mycetophagus quadripustulatus larvae
The larvae and adults of almost all species feed on the fruiting bodies of various fungi developing on trees and fallen timber, many undergo their entire life-cycle within such fungi and vary large populations may develop although they are rarely seen by day, careful searching by night will often reveal the adults in crevices around the fungi or even on the surface, and on warm and humid nights they may disperse across the surface of logs etc and are easily spotted. Tapping bracket fungi, especially those showing damage or with decayed areas, over a beating tray will often reveal numbers of adults alongside many other fungivore species. Some species are associated with decaying vegetation and some have been found infesting stored products, Typhaea stercorea (Linnaeus, 1758) being the obvious example but others e.g. Berginus tamarisci Wollaston, 1854, Litargus balteatus LeConte, 1856 and Mycetophagus quadriguttatus Muller, 1821 have also been recorded, in all cases they are very probably attracted to mould rather than the products. In the wild Berginus tamarisci has been observed feeding upon the pollen of Pinus pinaster Alton (maritime pine) and on the pollen and stamens of Selenicereus grandiflorus (L.) (Night-blooming cactus).
A key to the British species can be found HERE.