Eutrichapion ervi (Kirby, 1808)

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POLYPHAGA Emery, 1886

CURCULIONOIDEA Latreille, 1802

BRENTIDAE Billberg, 1820

APIONINAE Schönherr, 1823

OXYSTOMATINI Alonso-Zarazaga, 1990

Eutrichapion Reitter, 1916

This is a mostly central and northern European species; it is locally common from lowland to lower mountain altitudes from the Pyrenees to the Balkan Peninsula and rather more frequent in the north, extending into the UK and central provinces of Fennoscandia, to the east it extends into Central Asia and it has also been recorded from Algeria. In the UK it is generally common and often abundant across England and Wales though less so in the West Country and the north, it is present on the Isle of Wight, Anglesey and Man and is widespread though very local and sporadic in Scotland, extending north to Orkney, and Ireland. Typical habitats are open grassland, meadows, agricultural borders and coastal dunes and reservoir margins etc., less often in open woodland and scrub but they may be common on roadside verges, gardens and other disturbed places. Adults are present year-round; they are active from April until October and may occasionally occur during mild winter spells, they are diurnal and will usually be found in large numbers. Mating occurs in the spring and females insert a single egg into a host flower but in the early stages of development, in the UK the main host is Meadow Vetchling (Lathyrus pratensis L.) but they may also use other species of Lathyrus L and sometimes various vetches (Vicia L.). Larvae develop within the flower buds consuming the ovary and stamina, they pass through three instars and when fully developed they bore into the calyx, seal off a chamber, and pupate. New generation adults appear from mid-summer until the autumn, they remain generally remain on the host until the autumn when they enter the soil to overwinter. Adults become active when the temperature increases in the spring, they feed for a while before mating and this usually involves the larval host plants but they are also more widely polyphagous and have been recorded feeding on foliage of various Fabaceae including species of Coronilla L, Lens Mill, Lotus L. and Pisum L. Adults may be found by sweeping host plants and various Fabaceae, they often occur in open grassland with a good mix of herbaceous vegetation and are active during the warmest parts of the day, they often occur at ruderal sites and they fly well and so might suddenly occur at well-worked sites.

Eutrichapion ervi 1

Eutrichapion ervi 1

Eutrichapion ervi 2

Eutrichapion ervi 2

Eutrichapion ervi 3

Eutrichapion ervi 3

2.0-2.4 mm. Readily identified among our UK species by the colouration, smooth frons and glabrous scutellum. Dorsal surface and legs entirely black, male antennae entirely dark to pale orange, female antennae pale at the base and darkening to the apex, usually with the club black. Head with large oval and convex eyes and long and slightly diverging temples, surface punctured and with fine pale pubescence, especially around and beneath the eyes, frons with longitudinal grooves but without raised keels beside the eyes,  rostrum cylindrical and glabrous ventrally (at least in the distal half, and this may need to be examined very carefully) ; in the male weakly curved and about as long as the pronotum, in the female more strongly curved and about 1.5X longer than the rostrum, scrobes extending forward only to 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 weakly transverse, broadest and almost parallel-sided in the basal half and narrowed to a curved anterior margin, basal margin bisinuate, surface strongly and moderately densely punctured and with fine pale pubescence, in the basal half with a variable but always distinct longitudinal impression. Scutellum glabrous and smooth, without impressions or ridges. Elytra broadly-oval with sloping shoulders and broadest and strongly convex behind the middle, with well-impressed and punctured striae and broad, flat interstices, both of which have fine pale pubescence obvious at X20, the sutural stria not reaching the scutellary apex, the others almost reaching the elytral base. Legs long, robust and with rather dense fine pale pubescence throughout. Tarsi pseudotetramerous, the basal segment distinctly shorter than the others combined. Claws strongly toothed at the base.