Sitona lineatus (Linnaeus,1758)
A very common and often abundant species throughout England and Wales including Anglesey and Man but curiously there are no records from the Isle of Wight on the NBN (July 2009), further north there are scattered records across Scotland to Inverness and from the outer Western Isles and Shetland but not Orkney (Morris). They are common across our Watford area although numbers vary from year to year, some years they are abundant eg 2007, 2008 and some years they are simply common eg to August 2009, and occur in a very wide range of habitats eg open grassland, parkland, woodland, wasteland, roadsides and gardens etc, indeed it would be easier to list where they do not occur; during July and August they are often common on walls and billboards around the town centre. Hostplants include various clovers and vetches and the weevils are well known as pests of leguminous crops; according to Jackson (1920) they generally prefer peas, beans or vetches to clover, thus wild vetches growing in fields of clover are often stripped almost bare while the surrounding clover is untouched. Adults overwinter among long grass, straw or clover stubble and become active early in the spring feeding on young host foliage; feeding signs are characteristic starting with a U-shaped notch at the edge of the leaf, unopened leaves are also damaged often producing a symetrical pattern of holes when open. They may be observed mating throughout the spring and summer. The small oval eggs are laid in the soil from April to July and larve emerge after about 21 days. Newly emerged larvae make thier way to the root nodules upon which they feed, nodules in all stages of development are 'excavated' by the larvae and severe infestations may destroy the plants. Larval development takes around 6 or 7 weeks and when fully mature they measure up to 6.5mm in length. Pupation occurs in a cell about 5cm below the soil surface and adults emerge after about 17 days, numbers thus increase greatly during the summer when old and new generations occur together. New generation females up to five months old were found to have undeveloped reproductive organs (Jackson, 1920), by seven months these have devloped considerably except that the ovarian tubules remained undeveloped. This reproductive diapause ensures only a single generation a year.

Several Sitona appear very similar but lineatus will become obvious in the field; the elongate and parallel sided form and dull metallic colouration with paler longitudinal stripes are characteristic. Having said that , specimens will need to examined closely for a certain identification.

3.4-5.3mm (Morris) Upper surface scaling varies in colour; mostly metallic bronze to golden but also greenish or blue, in older specimens they may be missing, sometimes extensively so, so that the underlying shiny black cuticle is visible. Scales mostly round to oval and recumbent. Head and pronotum with fine elongate and pointed setae among the scales, obvious at X20. Head coarsely and closely punctured. Rostrum quadrate, scrobes angled down in front of eyes, narrowly visible from above. Eyes round and moderately convex. Vertex convex behind eyes. Central longitudinal furrow broad and deep, extending back to at least hind margin of eyes, basal extremity without a pit, this furrow may be obscured by scales and so will need to be examined from various angles. Antennal scape shorter than head across eyes (average 6:9), sinuate at base and abruptly thickened near apex. Funiculus 7 segmented; 1 and 2 elongate, 3-7 progressively shorter, club narrow and pointed. Scape red, funiculus and club darker. Pronotum shiny black and coarsely punctured, as strongly so or a little weaker than on head, with three longitudinal stripes of pale scaling. Lateral curvature characteristic; less strongly rounded anteriorly and so broadest a little behind middle. Front margin weakly raised. Scutellar scaling normal, as surrounding elytra. Elytra elongate, 2:1 or a little less, parallel sided and evenly rounded to apex. Striae strongly punctured to apex, interstices flat or weakly convex, shiny black and finely punctured, second and third of equal width before apex, without large erect setae (cf S.humeralis). Alternate interstices with rows of very fine pale semi-recumbent setae-like scales from behind middle to apex, laterally these extend further forward. Femora dark to almost black, clavate and without a ventral tooth. Tibiae and tarsi red. Claws separate ie not fused at base, strongly curved and without basal teeth.

Description from 12 Watford specimens at X20