Dryophilus Chevrolat, 1832

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POLYPHAGA Emery, 1886

BOSTRICHOIDEA Latreille, 1802

PTINIDAE Latreille, 1802

DRYOPHILINAE Gistel, 1848

D. anobioides Chevrolat, 1832

D. pusillus (Gyllenhal, 1808)

This is a small Palaearctic genus containing 10 species of which 3 occur in Europe and 2 extend to the UK; D. longicollis (Mulsant & Rey, 1853) is widespread in North Africa, South and Central Europe but absent from Britain. They are small beetles, 1.5-4.0mm, easily recognized among the UK fauna by the striate elytra and the form of the antennae; the last 3 segments are very elongate and the insertions are close together, about the length of the basal segment. All are drab coloured, black or brown with a wide, prognathous head and entire, very convex eyes. The vertex and frons are simply convex and the frons narrow between the antennal insertions, the antennae are 11-segmented and filiform with the last 3 segments greatly elongate. Pronotum near-quadrate and simply convex, without elevations, carinae or fovea and the lateral margins are curved and lack borders. Scutellum small but usually obvious, rectangular or narrowed apically. Elytra elongate-oval or sub-parallel, with distinct shoulders and continuously rounded apically, with well-impressed striae complete to the apex and an abbreviated scutellary striole, interstices rather strongly rugose and only indistinctly punctured.  Legs long and thin; femora curved and not, or only very weakly, broadened around the centre, tibiae only weakly broadened towards the apex, each with a single short apical spur, tarsi 5-segmented with the basal segments elongate and the terminal segment, unusually, dilated. The species are characteristically sexually dimorphic with males more slender and with a distinctly different pronotal shape, larger eyes, longer antennae and more slender tarsi.

Our UK species are readily separated:

-Pronotum transverse, scutellum without pubescence. Antennomeres 4-8 quadrate to elongate. Apex of basal sternite only gently curved. 1.3-2.0mm.

Dryophilus pusillus (Gyllenhal, 1808)

-Pronotum quadrate, scutellum with white scale-like pubescence. Antennomeres 4-8 transverse. Apex of basal sternite very strongly curved. 2.3-4.0mm.

Dryophilus anoboides Chevrolat, 1832

Dryophilus pusillus 1

Dryophilus pusillus 1

© Dave Hodges www.thewcg.org.uk

Dryophilus anobioides 1

Dryophilus anobioides 1

Dryophilus pusillus 2

Dryophilus pusillus 2

© Lech Borowiec http://www.cassidae.uni.wroc.pl/Colpolon/index.htm

Dryophilus pusillus (Gyllenhal, 1808)

This is the most widespread of the European species occurring from the Mediterranean east to the Caucasus and Egypt and north to southern Fennoscandia and the UK, here it locally common throughout England and Wales with the exception of the West Country and there are a few widely scattered records from the Scottish highlands. Adults appear from May until September and are associated with various conifer trees, more especially spruce but also pine and larch and fir. The typical habitat is mature conifer woodland where they may be found on damaged trees and fallen timber or swept from adjacent vegetation, they are mostly active at night when they fly and may be attracted to light; we have found them at light placed close to hedging conifers in Watford town centre. Larvae have been observed feeding on fresh larch shoots and adults have been reared from larvae developing on Larix decidua Mill. cones.

A small elongate species, 1.3-2.0mm, entirely dull grey or brown to almost black although this tends to be dimorphic, males having dark reddish elytra and females dark grey, dorsal surface with short pale pubescence. Head simply convex with eyes occupying the entire lateral margin, in males the eyes are much larger and the head is wider than the pronotum, in females the head is much narrower than the pronotum. Antennomeres 3-8 clearly elongate in the male, quadrate to slightly elongate in the female, segments 9-11 very elongate in both sexes. Pronotum transverse; evenly rounded in the female but widest behind the middle and strongly contracted to the base in the male, surface rugose and only obscurely punctured. Elytra broader than pronotum; sub-parallel with sloping shoulders in the male, weakly broadened posteriorly and with wider shoulders in the female; striae narrow, deeply impressed and unpunctured, interstices rugose although less strongly so than the pronotum and only obscurely, if at all, punctured.

Dryophilus anoboides Chevrolat, 1832

This is a local and generally rare western and central European species occurring from Spain and Algeria east to Slovakia and Poland and north to the UK. Here it is a very rare insect of southeast and central England. In the UK adults occur on broom, Cytisus scoparius, and larvae have been recorded feeding within the stems of Rubus fruticosa, on the continent they develop in stems and roots of broom but the biology is not well understood; in Germany adults are associated with larch and broom, in France mostly with pine and in the Netherlands with gorse, Genista. Here it may be under-recorded as the adults have a short season, from late April until June, and while they may be beaten or swept from broom they seem to be elusive, we have recorded it only once from broom on local scrubland despite having worked the site regularly for many years.

Dark brown to black, often with the elytra a little paler, and clothed with sparse short and pale pubescence. Distinguished from D. pusillus by the quadrate pronotum having antennomeres 3-8 transverse. Sexually dimorphic with males having longer antennae, narrower pronotum and more parallel-sided elytra with less developed shoulders.

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