EROTYLIDAE Latreille, 1802
Pleasing Fungus Beetles
Includes several widespread and common species while some are less abundant. With the exception of Cryptophilus integer, all are associated with fungal fruiting bodies.
POLYPHAGA Emery, 1886
CUCUJOIDEA Latreille, 1802
A large family of about 2500 species which are generally divided among 5 subfamilies. Erotylidae has a worldwide distribution but is primarily a tropical group. Only about 50 species occur in North America and 17 in Europe. Likewise in southern hemisphere temperate regions they are poorly represented; in New Zealand 8 species in 2 genera, one of which is endemic, and in Australia about 50 species. Tropical regions include brightly coloured species displaying a range of aposematic patterns and chemical defences and many exhibit gregarious behaviour. Pselaphacus nigropunctatus Percheron from Peru is noted for maternal care of the larvae. Adults and larvae of most species feed on the fruiting bodies of various fungi and because of their cryptic behaviour are rarely seen other than by entomologists and fungi collectors. A wide range of wood decay fungi are utilized, from agaricoles to polyporales, but each erotylid species seems to be specific to a certain group. Larger species e.g. Megalodacne feed on harder bracket fungi such as Ganoderma spp. found on dead trunks and stumps. Triplax spp. are associated mostly with oyster fungi, Pleurotus spp. on logs and trunks. Tritoma spp. feed on a range of fruiting bodies on stumps, logs and living tree roots. Development is usually rapid in these often ephemeral food sources and the larval stage passes quickly; two weeks from egg to pupa is not uncommon. Adults are often found away from the host fungi, usually under bark, but when the fungi is about to fruit they congregate close by, often in large numbers. Adults are often found upon or within the same fungi as the larvae. Many are active nocturnally and this is the best time to see them; tapping the fungus over a tray will usually produce a number of adults.
Size varies greatly, from around 2mm to about 25mm, although in temperate regions they rarely reach 10mm. Most species, and especially
those from tropical regions, are distinctively coloured, generally black with red and/or yellow and strikingly patterned. Temperate species tend to be bicoloured orange and black but a few e.g. Pseudischyrus and some Tritoma spp. are entirely dark. The body is usually glabrous and shiny (this applies to all the British species with the exception of Cryptophilus.) Antennae are 11-segmented with a 3-5 segmented gradual or distinct club. The terminal segment of the palps, and more especially the maxillary palps, are usually dilated. Elytra entirely cover the abdomen and the epipleura are complete to the apex. Coxae are usually widely separated. Tarsi in both sexes are 5,5,5. The larvae are elongate and cylindrical or slightly flattened, with a spiny surface or pubescent tubercles. The terminal abdominal segment bears either an upturned spine or a pair of short and upcurved or long and divergent urogomphi.
A key to the UK species can be found HERE.