Exomias pellucidus (Boheman, 1834)
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POLYPHAGA Emery, 1886
CURCULIONOIDEA Latreille, 1802
SCIAPHILINI Sharp, 1891
EXOMIAS Bedel, 1883
This species has a mostly central European distribution; it extends north into southern Fennoscandia and the UK and east at least as far as Moscow, it has also become established and widespread in the United States and Canada following introductions in the late 19th century and across various parts of its range it is a minor pest of soft fruits and other plants. Here it is generally common throughout England and Wales, including the Isle of Wight, Anglesey and Man, and extends sporadically and very locally north to Orkney. Adults appear from March until October and may be found in a wide range of habitats; beneath hedgerows, in open grassy heathland and moorland, roadsides dunes, parks and gardens and disturbed areas generally e.g. we once flooded an area of vegetated gravel beside a reservoir in South Herts to extract beetles and Exomias emerged from around grass tussocks in numbers. Adults feed on the underside of leaves and leaf-buds of a broad range of herbaceous plants e.g. aster, buttercups, dandelion, thistles and ragwort but also woody plants such as hawthorne or oak and may be present in large populations, thus they may become pests in nurseries, attacking plants rather opportunistically as seen in the United States where they have been a pest of young Christmas trees, the adults girdling the stems and so killing saplings. Hence the alternative common name of juniper root weevil. Damage caused by the adults is generally trivial but they oviposit in the soil around suitable hosts and larvae feed externally on tender roots and so when present in numbers may cause damage to nursery stock, especially where they retard the development of soft fruits. Oviposition occurs in May and June, and larvae develop through the summer; they pupate in cell beneath the soil surface and it is thought there may be two generations each year in warmer southern latitudes, in the UK the larvae probably overwinter in the soil and complete their development in the spring, giving rise to adults from March. Adults undergo a period of maturation feeding before mating occurs later in the spring, they are generally nocturnal but will also be found active on the ground surface or may be swept from grass and shrubs etc. during the summer.
Adults are small, 3.0-4.0mm, but very distinctive weevils; the pronotum and elytra are separately convex and rounded and the dorsal surface is characteristically pubescent, the striae bear short, semi-erect setae which contrast with a single row of long, erect setae along each interstice, the pronotum bears similar long erect setae. The body, including the rostrum, varies from very dark brown, almost black, to pale yellowish-brown while the appendages are reddish-brown. Head flat and rather strongly punctured throughout, with weakly convex eyes and parallel or diverging temples, rostrum shorter than the head-width and expanded at the antennal insertions, the surface longitudinally sulcate and bearing erect setae, scrobes lateral and deeply impressed. Antennae long and slender, the scape gradually thickened just before the apex and about as long as the funiculus; funiculus 8-segmented with the second segment longer than the others. Pronotum smoothly convex, without impressions; quadrate or slightly elongate or transverse, evenly curved laterally to well-defined obtuse anterior and posterior angles, surface very strongly punctured throughout and with quite dense long, pale setae. Elytra elongate-oval with sloping shoulders and a weakly acuminate apex, striae composed of regular rows of very strong punctures which fade towards the apex and appear to lie within longitudinal furrows towards the base and on the disc, here the interstices may be distinctly convex but towards the lateral margins and apex they are more or less flat. Legs long and robust; femora without a ventral tooth, tibiae sinuate internally and expanded apically forming a sharp, often hook-like process. Tarsi with two basal segments elongate, the third strongly bilobed and usually hiding the tiny fourth segment, and the terminal segment long, curved and expanded apically, claws connate.