Eutrichapion viciae (Paykull, 1800)

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POLYPHAGA Emery, 1886

CURCULIONOIDEA Latreille, 1802

BRENTIDAE Billberg, 1820

APIONINAE Schönherr, 1823

OXYSTOMATINI Alonso-Zarazaga, 1990

Eutrichapion Reitter, 1916

This species is locally common throughout the Palaearctic region and following introductions is now established and widespread though sporadic in North America, it occurs throughout Europe north to the UK and far above the Arctic Circle in Scandinavia and extends through Russia and Asia Minor to Japan and North Korea, it is generally absent from North Africa but is known from Iran and Syria. In the UK it is generally common across England and Wales though less so and more local in the West Country and the north, it extends into the Scottish Highlands and Outer Hebrides and is very local and sporadic in Ireland. Typical habitats include open grassland, heathland and coastal dunes exposed to the sun but the species is also typical of ruderal habitats and is often common on road verges and in gardens and allotments etc where the host plants are common. Adults occur year-round and are active over a long season from early spring and they may also occur during mild winter spells, peaks in abundance occur in the spring and again in mid-summer when the new generation emerges. Larval hosts include various Fabaceae but especially Lathyrus pratense L, and a range of vetches. Breeding occurs in the spring after a period of feeding and females lay single eggs into developing flower buds; they usually enter the bud through the unopened calyx but sometimes will chew through the side of the bud to lay the egg onto the anthers or the pistil. Larvae develop within the unopened bud consuming the anthers and pistil, they pass through three instars and when fully-developed move into the calyx where they construct a silken cocoon and pupate. The pupal stage lasts about seven days and adults emerge from mid-summer, they generally remain on the host plants until the autumn when they leave to enter the soil to overwinter. They emerge in the spring in response to increasing temperature and begin feeding; they generally consume emerging host foliage but at this time may also occur on other plants. Adults tend to occur in numbers where found and are easily sampled by sweeping, they are often common on disturbed ground because this is readily colonized by the host plants, wing development varies but fully-winged specimens are common and they may suddenly appear at well-worked sites in the spring.

Eutrichapion viciae 1

Eutrichapion viciae 1

Eutrichapion viciae 2

Eutrichapion viciae 2

1.9-2.4 mm. Readily recognized by the overall colour and the form of the scutellum and the frons. Elongate-oval, body entirely dark grey or black, legs dark with the femoral bases and the front tibiae to some extent pale, the middle tibiae are also sometimes obscurely paler at the base, antennae dark but variously pale towards the base, dorsal surface with recumbent pale pubescence. Head with large convex eyes and long diverging temples that are usually mostly retracted into the thorax, frons striate but without raised keels beside the eyes, pubescence long and dense around the eyes, forming distinct ventral ‘lashes’, rostrum slightly narrowed towards the apex; in the male about as long as the rostrum, in the female longer, the scrobes extending forward as far as the antennal insertions. Antennal scape longer than the rostral width, inserted about the middle of the rostrum in the male and well behind the middle in the female. Pronotum slightly transverse, sinuate laterally, broadest about the middle or towards the base and narrowed to a curved anterior margin, basal margin bisinuate, surface strongly and moderately densely punctured and with a variable but always distinct longitudinal impression in the basal half. Scutellum glabrous and without depressions or ridges. Elytra with sloping shoulders and broadest and most convex behind the middle, striae punctured and well-impressed to the apex; the sutural striae not reaching the scutellum, the others reaching the base or very nearly so, interstices much wider than the striae, almost flat and finely pubescent throughout. Legs long and robust, tarsi pseudotetramerous, the basal segment obviously shorter than the others combined, and all claws strongly toothed at the base.

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