Cryptophagus acutangulus Gyllenhal, 1827

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POLYPHAGA Emery, 1886

CUCUJOIDEA Latreille, 1802

CRYPTOPHAGIDAE Kirby, 1826

CRYPTOPHAGINAE Kirby, 1826

CRYPTOPHAGINI Kirby, 1826

Cryptophagus Herbst, 1792

Among the most widespread members of the family, this species has a Holarctic distribution which extends to China, Japan and North Korea; it is widespread across North Africa and the Middle East and established and widespread in Central and South America. Beyond this it is probably established in Tropical Africa and is regularly recorded throughout the world due to the trade in foodstuffs. The species occurs throughout Europe to the far north of Scandinavia; it is locally common in eastern and northern regions, becoming less so in the west, and it has been recorded as far north as Iceland and Greenland. In the UK it is locally common across the English midlands and East Anglia, there are older records from Northern England and Southern Scotland and it has been recorded from Ireland. In the wild the species is rather eurytopic; it occurs among decaying leaf litter in a wide range of habitats, under damp bark on a wide range of decaying or weakened deciduous and coniferous trees, among arboreal and terrestrial fungi, in mammal and bird nests and it has been recorded from old and dry carrion. The species is also synanthropic; it is regularly recorded from damp or decaying foodstuffs and from cargo ships carrying soybean meal and grain etc., it sometimes occurs in domestic dwellings and may be common among farmyard refuse or stored hay and straw. Both adults and larvae are mycophagous, feeding on spores and mycelia on decaying plant material and so in this sense it is not a pest, although adults fly and are known to transfer spores between host material. When adults were reared in the laboratory on Penicillium conidia it was found that about 15% of ingested conidia survive and that these have an enhanced germination rate. Adults may also be more generalist feeders as they have been observed feeding on dead insects and at carrion.  Under artificial conditions all life stages occur throughout the year and in warmer climates swarms of adults may disperse at any time although they seem to be photophobic and this usually occurs in the evening. In Northern Europe adults occur in the wild throughout the year, they remain active through the winter and peak in abundance during late spring and again in the autumn, suggesting spring breeding with new generation adults appearing in late summer and autumn and going on to overwinter, this may also account for the scarcity of adults during August and September. Adults may be sampled by sieving or extracting likely host material or by searching under bark, especially near to fungal infections.

Cryptophagus acutangulus

Cryptophagus acutangulus

© Lech Borowiec

1.8-2.6 mm. Very distinctive due to the large eyes and the form of the pronotum. Body finely punctured and with moderately dense pale pubescence throughout, entirely pale to dark chestnut-brown, appendages brown, the legs often paler than the body and the antennae often darker. Head converging in front of large asymmetric and coarsely-faceted eyes which occupy most of the lateral margin. Antennae 11-segmented; the basal segment large and globular, segments 2-8 elongate, and 9-11 forming a distinct club, the ninth segment virtually as wide as the tenth. Pronotum transverse and usually broadest across the greatly developed anterior calli which are rounded anteriorly, acutely produced at the apex and slightly upturned so that the lateral face is visible from above. Lateral margin curved and very finely dentate between the anterior calli and the central tooth, then more or less evenly narrowed to obtuse posterior angles. Surface evenly punctured across the disc and without sculpture, disc rather flat or only very weakly convex to widely depressed lateral margins. Scutellum widely transverse, expanded from the base and truncate apically. Elytra smoothly curved from rounded shoulders to a continuous apical margin that completely covers the abdomen, surface without striae although there is sometimes a weak sutural striae towards the apex, finely and randomly punctured throughout and uniform decumbent pubescence (without erect or semi-erect setae.) Legs slender and moderately long. Femora unmodified and all of similar width. Tibiae only weakly thickened from the base to rounded or oblique apices and without obvious apical spurs. Tarsi 5-segmented in females, 5-5-4 in males, all segments simple.