Anitys rubens (Hoffman, J., 1803)

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Genus:

POLYPHAGA Emery, 1886

BOSTRICHOIDEA Latreille, 1802

PTINIDAE Latreille, 1802

DORCATOMINAE Thomson, C.G., 1859

Anitys Thomson, C.G., 1863

This very local and generally scarce Western Palaearctic species has a rather patchy European distribution; it occurs from France to Ukraine in the south and while it is absent from much of south-eastern Europe, it does occur in Greece, to the north it reaches the UK, Denmark and into southern Fennoscandia but beyond Poland it seems to be absent from the Baltic region. The species also occurs in Egypt but is absent from North Africa and the Mediterranean islands generally. In the UK it is widespread across England and Wales as far north as York although it is generally absent from the West Country and much of the midlands; it is scarce throughout this range but likely to be under-recorded due to its lifestyle. Adults occur from February until September, peaking in abundance during May and June and again later in the summer. Typical habitats are ancient deciduous woodland and wooded parkland with plenty of older trees in various stages of decay; the species has been recorded developing in a range of broad-leaved trees but is most frequently associated with oaks (Quercus L.). Adults spend the day under bark or among decaying wood and are active on the surface during the evening and at night, the can fly but rarely do so and mating pairs have been observed in late spring and early summer. Females lay batches of eggs among decaying wood infested with fungi, most often in the vicinity of Laetiporus sulphureus (Bull.) Murrill (1920) or Fistulina hepatica (Schaeff.) With (1792) sporocarps. Larvae occur among red-rotten heartwood in old oaks, often at the base of larger branches and usually where this is infested with mycelia, and they often occur in dense aggregations. Larvae develop through the summer, they overwinter in situ and complete their development in the spring although in Northern Europe they have been recorded overwintering a second time, they do not spin a cocoon but form a pupal chamber from frass and wood dust from late winter and adults emerge in late spring and early summer. Curiously some adults seem not to leave the pupal chamber at all and pass their entire life within. Adults may be found by searching wood at night, they must be looked for very carefully as while they are slow-moving they will quickly roll-up into a ball when disturbed, retracting their appendages into grooves under the body, and become very cryptic; they sometimes appear in flight-interception traps placed in trees or in extraction samples from dead wood but only rarely so. On the continent they often appear alongside closely related species such as Dorcatoma chrysomelina (Sturm, 1837) or D. flavicornis (Fabricius, 1792) which share a similar biology and lifestyle.  

Anitys rubens 1

Anitys rubens 1

© U.Schmidt

Anitys rubens 2

Anitys rubens 2

© Lech Borowiec

1.9-2.0 mm. Strongly-rounded and very convex, almost hemispherical, extremely finely pubescent, shiny brown throughout or with the head and various patches on the pronotum darker. Head hypognathous and only narrowly visible from above, smoothly convex and without structure, eyes small, rounded and weakly convex. Antennae 8-segmented; basal segment enlarged and angled internally and the last three segments form an elongate and loose club. Pronotum broadly transverse, widest across rounded posterior angles and smoothly narrowed to obtuse anterior angles, surface finely punctured throughout, uneven but without distinct impressions or fovea. Scutellum small and triangular. Elytra smoothly curved from prominent, rounded but almost angled shoulders to a continuous apical margin, basal margin slightly produced into a curve or tooth medially, without striae but often with indistinct longitudinal impressions. Legs long and robust. Femora simple. Front tibiae sinuate and with fine spines across the curved apices, middle and hind tibiae straight with a tiny spur inside obliquely-transverse apices. Tarsi short, with transverse basal segments and an elongate apical segment. Claws with a variable basal tooth. The sexes may be determined by the form of the antennae; in males the seventh segment is slightly longer than the sixth, in females it is much longer. Distinguished among our UK species by the general habitus and 8-segmented antennae.