Phalacrus corruscus (Panzer, 1797)
POLYPHAGA Emery, 1886
CUCUJOIDEA Latreille, 1802
Phalacrus Paykull, 1800
This Palaearctic-wide species occurs locally throughout Europe, North Africa and the Near East; it is present on most of the Mediterranean islands and the Canaries and extends north to the UK, Denmark and the Baltic countries where it reaches into southern provinces of Norway and Sweden. In the UK it is widespread though very local and generally scarce throughout southern and central England and there are a few scattered records further north and from Ireland; it was formerly much more widespread, extending into Scotland, but seems to have declined significantly over recent years. Typical habitats are grassland and heaths but they are often common on agricultural land where cereals are grown, but adults tend to disperse readily in warm weather and so during summer and autumn may be swept from flowers, herbaceous plants or shrubs in a variety of habitats. Both adults and larvae feed on spores of parasitic smut fungi (Basidiomycota, Ustilaginales) developing on infected stems, leaves and seeds. Reproduction occurs during spring and summer and larvae develop during spring and early summer, pupating either in situ or in the soil. Adults occur year-round; they overwinter under loose bark or among tussocks etc, and are active from March until late in the summer, numbers peak from May until August and during this time teneral specimens are common. They are diurnal and can be sampled by sweeping or beating likely vegetation, and though very local they usually occur in numbers where found.
1.5-3.0 mm. dorsal surface strongly convex, underside flat, body and appendages entirely shiny black or, sometimes, with the tarsi dark brown. Head transverse, weakly convex and very finely punctured between convex eyes that follow the outline and almost parallel temples. Antennae placed laterally in front of the eyes, 11-segmented with a loose 3-segmented club, the terminal segment is very elongate (about 2.5X longer than wide) and longer than the two preceding segments combined. Pronotum strongly transverse, widest across perpendicular (in side view) posterior angles and smoothly narrowed to produced anterior angles, surface evenly convex and very finely punctured, lateral margins distinctly bordered, basal margin very finely so, at least across the middle. Scutellum large, triangular and punctured as the pronotum. Elytra slightly elongate, smoothly curved and narrowed from rounded shoulders to a continuous apical margin, each with a single sutural stria which is usually only evident towards the apex, and several finely impressed longitudinal lines, interstices finely and randomly punctured and with fine mesh-like microsculpture (X50). Legs short and slender with femora hardly visible in normal setting, tibiae gradually widened from the base to truncate apices, hind tibiae with short terminal spurs which are hardly visible among fine setae. Front tibiae with two or three short spines (distinct among the finer setae) on the outer apical angle.