A large family of small to medium (1-8mm) beetles, Nitulidae has 91 British representatives and are perhaps most familiar as tiny black beetles which flock to anything bright yellow on sunny summer days.  There are five subfamilies in Britain.

Meligethinae are small shining black beetles which feed as both larvae and adults on buds and flowers.  A wide range of plant families are attacked but each beetle species is highly host-specific, feeding almost entirely on a single plant species.  Two exceptions to this are Meligethes aenus (Fabricius) and M. viridescens (Fabricius), which feed on a wide range of Brassicaceae flowers and consequently have become pest species on oilseed rape and several other Brassica crops.

Carpophilinae consists of two genera, Carpophilus and Epuraea.  Carpophilus species are largely found in association with fungi, particularly on mouldy fruit, and consequently several species occur synanthropically and are known as stored-product pests.  Epuraea are less well known but appear to have diverse life-histories: several are found in association with wood-boring beetles, particularly Scolytinae spp. in conifers, while others develop in subterranean nests (particularly of bumblebees) and others are associated with fungi. Adults are frequently encountered on flowers and at sap runs.

Nitidulinae are another ecologically-diverse but largely unknown group.  Several species (particularly Nitidula and Omosita spp.) are associated with dried carrion and bones and many of the remainder are found chiefly in fungi.  Saronia grisea (L.) and S. punctatissima (Illiger) can be found mainly on sap runs, and in fermenting vegetable matter and the galleries of larvae of the goat moth, Cossus cossus (L.).  Amphotis marginata (Fabricius) is strongly myrmecophilous in the nests of Lasius fuliginosus Latreille.

Cryptarchinae are most often found on sap runs, although specimens are sometimes found in the galleries of wood-boring beetles, beneath bark, or further afield.  Little is known of their ecology.

Cybocephalinae consists of just one species in Britain, the 1-1.5mm Cybocephalus fodori Endrödy-Younga.  This is a predator of scale insects (Coccoidea: Diaspididae) which has been found on birch trees on Putney Heath, London.

A small family (9 British species) of small beetles (1.5-4.2mm), Kateretidae was formerly the subfamily Cateretinae within Nitulidae.  Small, dark beetles which feed on buds and flowers as both adults and larvae, they are similar in appearance to the pollen beetles (Nitulidae: Meligethes spp.) but can be separated by the truncate elytra which expose at least one abdominal segment, as well as the pygidium, and by the gradually-expanding antennal club. Kateretes spp. are common and widespread in wetlands where they feed on the flowers of Carex and Juncus spp., while Brachypterus spp. are found on nettles (Urtica spp.) and are widespread.  There are four Brachypterolus spp.: two, B. linariae (Stephens) and B. pulicarius (L.), are widespread in toadflax flowers (Linaria spp.), while B. vestitus (Keisenwetter) and B. antirrhini (Murray) are rare established introductions, occurring on Antirrhinum flowers in southern England

Two species in Britain, both small (2-2.5mm) black beetles with striate elytra and reddish appendages.  Sphindus dubius (Gyllenhal) is an elongate, parallel-sided beetle while Aspidiphorus orbiculatus (Gyllenhal) is rounded, even globular in appearance.  Both species are associated with slime moulds on trees.

The former family Melyridae has been split into two families, Dasytidae and Malachiidae. The latter contains 17 British species, which are often brightly-coloured soft-bodied beetles.  Larvae are predatory in dead wood, while adults are usually found in meadows (especially Malachius spp.) or trees (Hypebaeus and Aplocnemus spp.), both in foliage and beneath bark.  The species are often sexually dimorphic, with males having expanded antennal segments or complex processes at the elytral apices.

The former family Melyridae has been split into two families, Dasytidae and Malachiidae. Dasytidae contains nine British species in genus Dasytes, Psilothrix and Dolichosoma, and these mainly occur (as adults) in grassland, while larvae develop in wood, where they are predatory.  Dolichosoma lineare (Rossi) is a saltmarsh species of East Anglia and the Thames Estuary, Psilothrix spp. occur mainly in coastal grassland and dune systems in the south, while Dasytes spp. are found in flower-rich meadows.  Adults are elongate, dark-coloured metallic beetles with soft, easily-deformed elytra.

This small family includes 14 species recorded from Britain, all of which are local, rare, or probably extinct here.  Two species Thaneroclerus buqueti (Lefebvre) and Paratillus carus (Newman) are likely to accidentally-imported transient species, and four species, Tilloidea unifasciatus (Fabricius), Trichodes alvearius (Fabricius), T. apiarus (L.) and Tarsostenus univittatus (Rossi) have not been seen since the 19^th century and are likely to be extinct.

Medium-sized (6-16mm) beetles and often brightly coloured, attractive, species, they are associated with stored products, carrion and trees.  Necrobia spp. scavenge dead flies and fly larvae while several other species (particularly Tillus elongatus (L.), Korynetes caeruleus (De Geer) and Opilio mollis (L.)) are predatory on Anobiidae.

There are only five species of Trogossitidae in Britain, but they have a diverse ecology.  One, Lophocateres pusillus (Klug), is a stored product pest found only in artificial conditions.  Thymalus limbatus (Fabricius) and Ostoma ferrugineum (L.) are found beneath bark, the former frequently and the latter rarely, in Caledonian forest remnants in association with the dyer’s polypore fungus Phaeolus schweinitzii (Fr.) Pat.  Of the remaining species, Tenebroides mauritanicus (L.) is a pest of cereals and Nemozoma elongatum (L.) is a rare predator of Acrantus vittatus (Fabricius).

A single species in Britain, Phloiophilus edwardsi Stephens.  This is a small (2-3mm) species, slightly dorso-ventrally flattened, and patterned with in black and mid-brown with strongly-protuberant eyes.  It is found in association with the fungus Peniophora quercina (Persoon) Cooke.

Two species in Britain, Hylecoetus dermestoides (L.) and Lymexylon navale (L.).  They are medium-sized (7-18mm) orange and black beetles, resembling Cantharidae with soft, pubescent elytra but unlobed tarsi.  Both species are woodborers, and are associated with wood pasture and woodland.  Lymexylon navale is mainly found in the southeast, while H. dermestoides is largely found north of a line between the Severn and the Wash.

There are 56 British species in this family, which also contains the former family Anobiidae.  Most species are small (1-7mm) woodboring beetles, though others are found in stored produce.  There are eight subfamilies in Britain.

Eucradinae is represented by a single species, Hedobia imperialis L., the larvae of which bore Rosacea shrub species.  Adults are 4-6mm long and pubescent, with a grey X across the elytra, and can be found by beating old hedges of hawthorn.

The spider beetles are subfamily Ptininae, and there are 22 British species.  Mostly with globular abdomens and yellow-pubescent appendages, the resemblance to a spider can be striking.  Generally found amongst stored products or old timber, often in buildings.

Subfamily Dryophilinae contains just three British species, two of Dryophilus and one Grynobius.  Grynobius planus (Fabricius) is widespread but local in dead hedges and decaying timber, 4-6mm long with black to dark-red elytra.  Dryophilus pusillus (Gyllenhal) is locally common in association with conifers, and D. anobioides Chevrolat is a Breckland species, where it is found in broom Cytisus scoparius (L.).

There are eight species of Ernobiinae in Britain, including the deathwatch beetle Xestobium villosum (De Geer). The six Ernobius spp. develop in conifers, particularly pines, while X. villosum is found in broadleaf timber and Ochina ptinoides (Marsham) can be found in ivy.

Anobiinae includes nine British 2-6mm species, most famously Anobium punctatum (De Geer), the archetypal woodworm.  Adults have a humped pronotum and all develop in dead wood, with the exception of Stegobium paniceum (L.), the biscuit beetle, which is a pest of stored products.

Ptilininae includes a single British species, Ptilinus pecticornis (L.).  This species is readily recognised from the antennae, which in the female are broadly serrate and in the male, strongly pectinate.  A woodboring species, large swarms can occur around the host tree in late spring and early summer.

Xyletininae has two British representatives, the more abundant of which is Lasioderma serricorne (Fabricius), the cigarette beetle.  Local but widely distributed, it is a 3mm, shining red, finely-punctate pest of dried vegetable products, including tobacco.  The scarce Xyletinus longitarsus Jansson is larger (3-4mm) and found in wood across southern England.

Dorcatominae has 10 rare species in Britain.  2-3mm long, all are short, round beetles with charactistic lobed antennal segments expanded on the inner edge.  The group includes fungivores (Caenocara spp.) and woodborers.