Cortinicara gibbosa (Herbst, 1793)
Native to the Palaearctic region, this tiny but very resilient species is now cosmopolitan, having been transported along with the spread of humans over recent centuries, it is most prevalent in temperate regions and is an occasional pest of stored foodstuffs such as rice, millet and wheat, especially where these have acquired moisture during storage, and it has been reported as a major pest of kiwifruit in China. It is generally abundant throughout Europe north to the UK and above the Arctic Circle in Fennoscandia, it is present on the Mediterranean and Atlantic islands, across North Africa and well as the Faroe Islands and Iceland and is one of the few beetle species on Svalbard, it was first recorded in the United States during the nineteenth century and is now established and widespread north to Alaska. Here it is one of our most common beetles across the south of England and Wales, rather less so north to the Scottish border and rare and sporadic further north to the highlands. Adults occur in a very wide range of habitats, they are probably most common in open and damp environments such as dunes, heaths, marshlands, meadows, bogs and grasslands but are also common in both deciduous and coniferous woodland, parks and gardens, and may be super abundant on blossom in the spring, especially on hawthorn. Adults occur year-round, they may be found by beating or sweeping foliage and are often common among compost and leaf-litter, during the winter they may turn up in samples of fungi or litter, bark, tussocks and flood refuse etc. and are often common among old bird nest material. Larvae live among decaying plant matter and are thought to feed on fungal spores associated with decay while adults are known to feed on fungi and bacteria and also directly on plant material. Because the adults graze moulds etc on the surface of decaying vegetation they have become very versatile pests and will infest any damp products, when feeding on fruits they often consume the skin and flesh to a depth of several millimetres and ruin the produce by leaving hard brown scars across the surface, and because moulds tend to grow on packing materials as well as stored foods the beetles and their larvae can survive and develop in crevices etc in the absence of crops.
1.0-1.4mm. Without experience these tiny beetles can be very difficult to identify but the present species should soon become familiar through its abundance and (with experience) characteristic appearance. Chestnut brown when mature, often with the forebody a little lighter or darker than the elytra, legs pale and antennae pale with the club a little darker, dorsal surface with fine pubescence that forms regular rows on the elytra. Head coarsely punctured, about as strongly as the pronotum, with large, coarsely-faceted eyes, short and usually indistinct temples and a distinct frontoclypeal suture. Antennae longer than the head and pronotum combined, 11-segmented with a loose three-segmented club, segments 9 and 10 only slightly elongate. Pronotum transverse (about 1.4:1) and broadest in front of the middle, lateral margin smooth or very finely crenulate, distinctly angled (specimen may need to be tilted to appreciate this) and narrowed to a rounded anterior margin and slightly protruding posterior angles, surface evenly and quite strongly punctured throughout and with a transverse impression before the base that extends to the lateral margins. [Prosternum without a process, the coxae contiguous-a feature that will distinguish Corticariinae from Latridiinae] Scutellum triangular and slightly transverse. Elytra broadly elongate; about 7:5 and at the widest point near the middle about 1.7X the pronotal width, interstices flat and almost as strongly punctured as the striae, the punctures setose as those of the striae so that the striae appear to be numerous; 8 or 9 between the suture and the shoulder, lateral margin smoothly curved to separately rounded apical margins. First visible abdominal sternite without lines extending from the coxae towards the apical margin. Legs slender and relatively long, femora and tibiae without teeth or terminal spurs, tarsi 3-segmented; the basal segments short and weakly lobed ventrally, and the terminal segments long and curved. Claws smooth and with a small basal tooth.