Vanonus brevicornis (Perris, 1869)

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Genus:

POLYPHAGA Emery, 1886

TENEBRIONOIDEA Latreille, 1802

ADERIDAE Csiki, 1909

Vanonus Casey, 1895

This very local and generally scarce species has a very patchy European distribution from France and Northern Italy to southern Fennoscandia, and in many countries e.g. Denmark, France and Germany. It is known from only a few sites, the eastern extent of this distribution is probably the Czech Republic and to the west it is represented by ssp. rotundicollis Israelson, 1971 on the Canary Islands. In the UK it is known from a few scattered records from southern England, Berkshire, Buckinghamshire, South Devon, Hampshire, Kent, Sussex, Bedfordshire and Suffolk, and while it is very rare it seems to be stable at a few sites. Adults occur over a short season from June or July into August and are usually associated with old deciduous trees growing in open situations exposed to the sun, they are mostly nocturnal and often attracted to decaying soft bracket fungi on which they are thought to feed. They generally occur low down on trunks or stumps and have been found on the ground beside moss-covered stumps, they disperse by flight and at such times may occur in numbers on foliage beside stumps and trunks, they occur in flight-interception traps placed in hollows or low down on trunks with areas of soft decaying wood, and are sometimes attracted to light. Little is known of the biology but larvae develop among decaying heartwood in various broad-leaved trees, perhaps predominantly Beech (Fagus sylvatica L.) and oak (Quercus L.).

1.5-2.0 mm. A tiny elongate species with a broad head, narrow pronotum and long elytra, head black or dark grey, pronotum and elytra reddish-brown to dark brown, appendages lighter brown, entire body finely pubescent. Head transverse and a little wider than the pronotum, with convex and finely pubescent eyes and short, angles temples in front of a broad neck, surface discretely and moderately strongly punctured throughout, terminal maxillary palpomere strongly securiform. Antennae inserted laterally in front of the eyes, the insertions visible from above, segments 1-3 slightly elongate, the third segment longer or at least as long as the fourth, 4-6 quadrate, and 7-11 forming a long and loose club. Pronotum transverse, broadest about the centre and narrowed to a curved anterior margin, the basal half only slightly narrowed to obtuse posterior angles, surface uneven and coarsely punctured throughout. Scutellum transverse, narrowed from the base to a truncate apical margin and punctured and pubescent  as the pronotum. Elytra much broader across the base than the head and pronotum, with rounded shoulders and a continuously rounded apical margin, widest about the middle or almost parallel-sided, surface rather flattened and usually with a vague oblique impression from the shoulders, densely punctured and finely uneven throughout. Legs long and slender, the hind femora broader than the others and all tibiae only slightly broadened from the base, the middle and hind tibiae with a very fine and hardly noticeable terminal spur. Tarsi 5-5-4, the basal segment long and the fourth tiny and often hidden within the lobes of the preceding segment.

Vanonus brevicornis 1

Vanonus brevicornis 1

© Mark Telfer

Vanonus brevicornis 2

Vanonus brevicornis 2

© Udo Schmidt