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Rhizophagus cribratus Gyllenhal, 1827






POLYPHAGA Emery, 1886

CUCUJOIDEA Latreille, 1802

MONOTOMIDAE Laporte, 1840

RHIZOPHAGINAE Redtenbacher, 1845

Rhizophagus Herbst,1793

A very widespread Palaearctic species known from Europe to Mongolia and the far east of Russia; in Europe it occurs from the Pyrenees to the Balkan Peninsula, extending south into central Italy, and north to the UK and into Northern provinces of Norway, Sweden and Finland. The species occurs from lowlands to middle lower mountain altitudes and is local and rare in western and central areas, becoming more common in the north and east. In the UK it is widespread though very local and generally rare throughout England, Wales, Southern and Central Scotland and Ireland. The typical habitat is deciduous and mixed woodland where it is associated with a range of broadleaf trees, especially oaks, and much less frequently various conifers, but it is sometimes recorded from compost and rubbish-heaps in a range of situations. Adults occur throughout the year; they are active from March until late in the autumn and they peak in abundance during May and June. Mating occurs mostly in the spring but pairs may sometimes occur in the autumn, eggs are laid under bark or in decaying wood and larvae develop through the summer. Both adults and larvae are probably saprophagous or detritivores, but larvae are sometimes quoted as predatory on early stages of other saproxylic beetles as they often occur in bark beetle galleries. Adults occur under bark, often low down on trunks or even among the roots, among fungi or at sap, they are mainly nocturnal and they fly well, sometimes occurring in flight-interception traps. They overwinter among moss or litter about the base of old trees but may appear under damp and loose bark during mild spells, they rarely occur in numbers and sometimes among other more common members of the genus.

Rhizophagus cribratus

Rhizophagus cribratus

3.0-3.8 mm. Elongate and narrow, discontinuous in outline, dorsal surface with extremely finely pubescent, entirely dark reddish-brown, appendages often a little lighter. Head smoothly convex between small and protruding eyes and long converging temples, moderately strongly and densely punctured, clypeus more finely so, anterior clypeal margin smoothly rounded. Antennae inserted laterally on long converging cheeks, 11-segmented with a large and truncate club appearing to consist of only the tenth segment, segment 11 diminutive and not visible. Pronotum quadrate or nearly so, broadest in front of the middle and narrowed to rounded angles, lateral margin uneven but not distinctly toothed, surface evenly convex, without structure and strongly but not densely punctured. Elytra gently curved from rounded shoulders to a narrow and continuous apical margin, striae evenly punctured from the base and more or less parallel throughout, interstices flat, without larger punctures and much broader than the striae. Legs short and robust, femora unarmed, tibiae rather strongly broadened from the base to truncate apices, the outer margin with several very fine teeth (usually only visible on the middle tibiae). Tarsi 5-segmented in females, 5-5-4 in males.

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