Apoderus coryli (Linnaeus, 1758)

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POLYPHAGA Emery, 1886

CURCULIONOIDEA Latreille, 1802

ATTELABIDAE Billberg, 1820

APODERINAE Jekel, 1860

APODERUS Olivier, 1807

This very distinctive beetle is widespread and locally common throughout most of Europe, The Middle East and western Asia; in the U.K. it occurs across England and Wales and there are a few records from southern Scotland. The typical habitat is deciduous woodland where the host, hazel, occurs but adults fly well and disperse in hot weather and so occasionally occur in parks and gardens. Other trees have been recorded hosting the species e.g. alder, birch, hornbeam (especially on the continent) and beech but this is rare. Adults appear during May and spend some time maturation feeding, which may be recognized as fairly large holes within the leaves, before mating. Oviposition begins in May and extends through June; the small, 1-1.5mm, bright yellow eggs are laid in the centre of a leaf towards the tip, usually singly but sometimes two or three together. The female then cuts obliquely through the leaf, generally near the middle, and may walk along larger ribs nibbling them at intervals so that they will fold, and rolls the leaf obliquely from the apex to form a short cylinder which will hang beneath the intact basal part of the leaf. If small the entire leaf may be rolled, and eggs are sometimes laid into the roll as it is being formed. This rolling generally takes between sixty and ninety minutes and each female will produce several rolls each day and about thirty in total. Larvae emerge after about ten days and develop inside the roll; they pass through only two instars and pupate within the roll, producing new generation adults in July and August. Late summer larvae develop in the rolls and are mature by the autumn, these will overwinter in rolls that drop to the ground; pupation occurs in the spring and adults eclose in early May. In southern continental regions second generation adults often eclose in the autumn and overwinter in the rolls. Adults may be sampled by beating or sweeping foliage, they also bask and fly in hot weather and are easily spotted. During late spring their presence may be detected by the adult feeding holes which may be extensive when several are present. The larvae are a distinctive bright orange with a darker head and up to 10mm when fully grown; the pupa is also bright orange, and up to 8mm in length.

This species is unlikely to be confused with any other in the U.K. 5.9-8mm. The head is entirely black or sometimes reddish laterally, shiny and finely punctured and transversely wrinkled. The temples are long; bulbous in the female and tapering in the male, the eyes strongly convex, the frons more strongly punctured and obliquely furrowed inside the eyes. The rostrum is only slightly elongate, moderately punctured and raised over transverse scrobes. Antennae entirely black, orthocerus, inserted apically in the scrobes and the terminal three segments form a weak and pubescent club. The pronotum lacks lateral borders, is pale or sometimes with obscure dark marks, shiny and glabrous and very finely punctured. There are usually transverse furrows behind the anterior margin and in front of the base. The scutellum is black, large and rounded, and raised towards the apex. Elytra red, slightly elongate with well-developed shoulders and each a well impressed sutural stria and ten rows of large punctures which may become confused on the disc. The cuticle is finely punctured and transversely rugose. Legs long and robust; coxae and trocanters black, femora clavate; red but generally darkened at the base and in the apical third, tibiae red with the base and apex to some extent black, the inner margins finely toothed and the apex with a single apical tooth. Tarsi 5-5-5 but may appear four segmented as the fourth is small and may be obscured by the lobes of the third segment. Claws smooth and connate.