Stenocorus meridianus (Linnaeus, 1758)
POLYPHAGA Emery, 1886
CHRYSOMELOIDEA Latreille, 1802
LEPTURINAE Latreille, 1802
RHAGIINI Kirby, 1837
STENOCORUS Geoffroy, 1762
This species occurs throughout Central and Southern Europe, from the Mediterranean north to the UK and southern provinces of Scandinavia and from France east through the Caucasus, Kazakhstan and Russia to lake Baikal, here it is widespread and locally common throughout England north to the Humber and more sporadic and local further north to the Scottish border, in Wales it is mostly absent from the west and it does not occur in Ireland. Through much of mainland Europe it has declined in recent decades due to ignorant woodland management and in many northern areas it is now rare, in central Europe it occurs mostly in foothills and low mountain habitats; in the Alps up to 2200m. The typical habitat is open or fragmented broadleaf woodland with plenty of marginal vegetation, often in areas exposed to the sun and hosting a variety of flowers. Adults have a short season, generally June and July although during a warm spring they may be active from mid-May and in some years they persist until August. They are active in bright sun; early in the season they visit flowers, especially various Apiaceae, Rosaceae and Compositae, where they feed on pollen in order to mature, and at this time they may be seen in numbers both in flight and on flowerheads, occasionally pairs may be seen mating on flowers but this usually occurs on the ground or low down on trunks. Hosts include a wide range of broadleaf species e.g. oaks, elms, birches, willows, ash, poplars and alder, they have also been recorded from fruit trees in orchards and gardens, and it is thought that the age and condition of the wood, or perhaps the presence of fungi is more important in deciding a host than the species. Females oviposit in the soil next to decaying stumps, fallen timber or among roots and may move between sites to do so, larvae enter the wood and feed initially under bark, but larger larvae also penetrate the xylem , development takes two or three years and fully-grown larvae measure 3.5-4.0cm. Developing larvae have been recorded from roots with a diameter between 0.5 and 6.5cm. Pupation occurs in a cell between among decayed wood or in the soil between 5 and 10 cm below the surface and although adults may eclose during the autumn or winter they remain in the cell until the spring, in general though it is thought that pupation occurs in early spring in response to increasing temperature. Adults are very distinctive and easily seen on flowers or as they fly slowly around trees or umbels in the sunshine, otherwise they remain on trunks or among foliage and may occasionally be swept.
Among the largest of our species at 15-25mm, this is an unmistakable longhorn despite the very variable colour of the elytra; elongate with wide, projecting shoulders and narrow pronotum, the elytra strongly narrowing towards the apex in the male, less strongly so in the female. Entire dorsal surface with fine golden pubescence, head and thorax black, elytra variable from black to pale brown or dark with the shoulders and/or suture paler etc. Head finely punctured and rugose, longitudinally depressed between convex and protruding eyes, temples long and evenly narrowed to the base. Antennae dark but usually with at least the basal segment pale. Pronotum elongate, without lateral borders but with a large tubercle near the middle of the lateral margin, disc with a longitudinal impression and transversely constricted behind the anterior margin and in front of the basal margin. Elytra flattened towards the base, becoming gradually convex apically, without regular striae but usually with a longitudinal impression at the base, apices truncate, surface transversely rugose, with very fine as well as larger punctures which may tend to form distinct rows in places. Legs slender and very long, mostly mid to dark brown with the apices of the femora and tibiae, and usually the entire tarsi, black or at least much darker. Tarsi 5-segmented; pseudotetramerous with the basal segment notably long and slender, almost cylindrical; on the mid and hind tarsi longer than the next two combined.