Leiosoma deflexum (Panzer, 1795)

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POLYPHAGA Emery, 1886

CURCULIONOIDEA Latreille, 1802

CURCULIONIDAE Latreille, 1802

MOLYTINAE Schönherr, 1823

MOLYTINI Schönherr, 1823

Leiosoma Stephens, 1829

This western Palaearctic species has a mostly central and southern European distribution; it occurs from lowland to subalpine regions and is locally common across the south, it extends north to the UK, Denmark and into southern Fennoscandia where it is very local and sporadic. In the UK it is generally common across Wales and southern and central England, common though much more local in the West Country and further north to the Scottish border, and sporadic and rare further north to Orkney and in Northern Ireland. Typical habitats are damp grassland, marshes, shaded river valleys and scrub with abundant and varied herbaceous vegetation. Adults occur year-round, they overwinter among tussocks or moss etc and are active over a long season from March until August or September; they are usually common where they occur but spend much of their time among foliage close to the ground and so are rarely swept in numbers. Reproduction occurs in spring and early summer and larvae develop in or among the roots of various Ranunculaceae, recorded hosts include Wood Anemone (Anemonoides nemorosa (L.) Holub), Marsh Marigold (Caltha palustris L. and various varieties), buttercups (Ranunculus L, including R. repens L. and R. montanus Willd).  Adults are mostly diurnal and although they tend to be elusive and are often missed when sweeping, they may be active higher up on foliage during warm summer nights and here they may occasionally occur in numbers.

2.4-3.0 mm. A tiny but very distinctive weevil, convex with separately-rounded pronotum and elytra and a broad and strongly down-turned rostrum, entirely shiny black with the antennae (except for the club), tarsi and at least the apical part of the tibiae reddish. Head transverse and retracted into the thorax to the posterior margins of weakly-convex eyes, vertex and frons with various longitudinal impressions, rostrum almost as long as the pronotum (compare in lateral view), distinctly widened apically and with oblique lateral scrobes that are narrowly visible towards the apex, dorsal surface with setiferous punctures that usually form more-or-less distinct longitudinal rows. Antennae inserted laterally just before the rostral apex, scape gradually thickened from the middle to the apex, funiculus 7-segmented and club broad and pointed. Pronotum transverse, broadest about the middle and narrowed to a rounded anterior margin, behind the middle almost straight and slightly narrowed to obtuse posterior angles, surface with discrete and very strong punctures, each with a short pale seta. Metepisterna with dense pale pubescence (visible in lateral view between the middle and hind legs). Elytra elongate, broadest about the middle and smoothly rounded from sloping shoulders to a continuous apical margin, striae consist of complete rows of very strong punctures and each interstice with a single row of much smaller punctures, all of which bear a small pale seta. Legs long and robust, all femora with a small ventral tooth (which is easily missed and must be searched for very carefully), front tibiae with a small internal tooth apically, middle and hind tibiae simple, tarsi pseudotetramerous. Males are a little narrower and have the first abdominal sternite broadly impressed, they also have a slightly shorter and wider rostrum but this is comparative.  Distinct among our UK members of the genus in having toothed femora.

Leiosoma deflexum 1

Leiosoma deflexum 1

Leiosoma deflexum 2

Leiosoma deflexum 2

Leiosoma deflexum 3

Leiosoma deflexum 3

Leiosoma deflexum 4

Leiosoma deflexum 4