Common name: Round fungus beetles
Number of species: 95
Size Range: 1-7mm
Tarsi: 4-3-3, 5-3-3, 5-5-4, 5-5-5.
Description:
A family of 93 small (1-7mm) round/oval beetles in Britain, largely found in association with fungi. Much of the biology and ecology of these beetles is unknown, partly because species-level identification is exceptionally difficult, particularly Leiodes and Colon species. There are four British subfamilies.
Subfamily Platypsyllinae has only one British representative, the brown, hairy Leptinus testaceus Müller. This has been found in various nests: those of bumblebees, birds, rodents and the ant Formica fuliginosa Latreille.
Coloninae contains a single genus in Britain, Colon, and nine brown, smoothly-oval species. The ecology and biology of these species is particularly poorly known and identification is difficult, especially of females: the most reliable method of identification is to examine the aedagus of the male.
Cholevinae has 34 members in Britain, and occur in decaying organic matter of various types. Most species of genus Choleva can be found in mammal nests; Nemadus colonoides (Kraatz) occurs in bird nests in tree rot-holes and Catopidius depressus (Murray) is found mostly in rabbit burrows. As with Coloninae, the aedagus is the primary identification tool, although in genus Choleva the male posterior trochanters and female genital sclerites are also characteristic.
Leiodinae has 49 shining black-brown round-oval species on the 2012 checklist, mostly mycophagous and many almost unknown. The tribe Leiodini have fossorial legs; they, along with the tribe Sogdini, live mostly underground where they feed on hypogeous fungi, including truffles (Tuber spp.). Other groups can be found in association with above-ground (epigeal) fungi and myxomycetes (slime moulds), including under fungoid tree bark and in leaf litter. As with the other Leiodidae, dissection of the male is the most reliable method of identification.
The round fungus beetles (Leiodidae) are a large family (500 species) with worldwide distribution. 85 species are known to occur in Germany. All of them feed on fungi. The species of the tribe Leiodini live on subterranean fungi and are equipped with fossorial legs, whereas the tribe Agathidiini feeds on above-ground fungi (also on tree fungi). The species of the genus Agathidium are able to curl up into a ball if disturbed. Many subterranean species leave the soil at dusk and can be catched on glades and riverbanks by using a sweeping net.
Leiodidae is a family of beetles with around 3800 described species found worldwide. Members of this family are commonly called round fungus beetles due to the globular shape of many species, although some are more elongated in shape. They are generally small or very small beetles (less than 10 mm in length) and many (but not all) species have clubbed antennae.
Members of the family are generally saprophagous or scavengers feeding on carrion or decaying organic matter like dung, or are specialised on feeding on specific types of fungus. Many species have reduced wings, with about half of all described species being flightless.
The oldest fossil of the family is Mesagyrtoides from Shar-Teg, Mongolia, dating the Late Jurassic (Tithonian). Members of modern subfamilies appear during the Cretaceous, with Cretaceous members of the family being primarily known from Burmese amber.
