DIAPERINAE Latreille, 1802
Mostly local species in a variety of habitats. Occuring both coastal and inland. Includes several pest species.
This large subfamily includes 11 tribes, of which 8 occur in the Nearctic region and 9 in the Palaearctic; about 450 species occur in the Palaearctic region of which 26 species in 7 tribes are European. The U.K. fauna includes 15 species in 10 genera and 7 tribes. The group is almost cosmopolitan, occurring throughout the world with the exception of New Zealand and many oceanic islands, and the greatest diversity by far is in the Oriental region. Among the European fauna the subfamily is distinctive; they are small to medium-sized beetles, 1.5-8.5mm, broad to elongate-oval and very convex to cylindrical. The antennae are generally relatively short and widened apically or clubbed, the insertions concealed by the genae, and there is an exposed membrane between the clypeus and labrum. The eyes are weakly emarginate anteriorly and often partially divided by the genae. The tarsi are 5-5-4 with no bilobed segments, the claws are smooth and there is an exposed membrane between the basal abdominal ventrites. Many species are associated with fungal fruiting bodies.
Diaperinae Latreille, 1802 includes 15 species in 10 genera and 6 tribes. The Crypticini Brullé, 1832 includes the single species Crypticus quisquilius (Linnaeus, 1760), a very local species of coastal sand dunes and shores, with occasional inland records from sandy areas. Phaleria Latreille, 1802 includes the single species P. cadaverina (Fabricius, 1792) and is our only member of the Phaleriini Blanchard, 1845, it is a locally common species of shores and dunes occurring under debris and in the sand around the roots of plants or among buried seaweed; the adults sometimes occur in large numbers and may swarm on warm days. Myrmechixenini Jaquelin du Val, 1858 includes 2 species of Myrmechixenus Chevrolat, 1835 and is unique among the U.K. tenebrionid fauna in having the 4-4-4 tarsal formula. Formerly included in the Colydiidae our 2 species are very rare or no longer occur here; M. subterraneus Chevrolat, 1835 is myrmecophilous, associated with various species of Formica, but has not been recorded since 1970 while M. vaporariorum Guérin-Méneville, 1843, associated with fermenting compost heaps and heated greenhouses, has only been recorded from Worcester and Hampshire since 1970. Hypophlaeini Billberg, 1820 includes 4 species of Corticeus Piller & Mitterpacher, 1783,
all are saproxylic and often found in the galleries of other wood-boring beetles where they have been observed predating larvae and consuming frass, and adults often occur in numbers. Some species may have specific host associations e.g. C. bicolor (Olivier, 1790)is associated with Scolytus scolytus (Fabricius, 1775) in elm; during the 1970’s there was a huge increase in numbers along with the spread of Dutch elm disease. C. linearis (Fabricius, 1790) is associated with the scolytid Pityogenes bidentatus (Herbst, 1784) on conifers. All species are locally common across England and Wales. Scaphidemini Reitter, 1922 includes the single species Scaphidema metallicum (Fabricius, 1792), a widespread though local saproxylic species occurring near fungal fruiting bodies on broad-leaved trees throughout England and Wales except for the far north. Diaperini Latreille, 1802 includes 6 species in 5 genera. Diaperis boleti (Linnaeus, 1758) occurs on bracket fungi on broadleaved trees and is particularly associated with Laetiporus sulphureus (Bull.) on birch and beech, formerly very rare this species has become more widespread and common over recent decades. Platydema violaceum (Fabricius, 1790) is a very rare saproxylic species recorded from fungi on oak, alder and elm and occasionally at light from a few sites in Hampshire and Surrey. Pentaphyllus testaceus (Hellwig, 1792) is associated with fungi, decaying trees and leaf mould on the continent, its inclusion on the U.K. list is based on a single record from North London in 1876. Alphitobius bifasciatus (Say, 1824) is a mould-feeder, occurring in the wild among decaying vegetable matter e.g. beneath hay stacks, and also inside among stored food products in granaries etc., it is a local species with records throughout England and Wales, and adults may occur in large numbers among stored grain etc. Two species of Gnatocerus Thunberg, 1814 have been recorded as pests of stored products; G. cornutus (Fabricius, 1798) is widespread and regularly recorded among a wide range of stored animal and vegetable products while G. maxillosus (Fabricius, 1801) is only occasionally recorded among imported vegetable products.