Curculio villosus Fabricius, 1781
Locally common across the Palaearctic region to the far east of Russia, this species occurs throughout Europe except for the far north and is widespread in North West Africa, it is locally common across Wales and the south of England although generally absent from the West Country, and more sporadic and scarce further north to the Scottish border. Adults occur year-round but are usually active from April until July; typical habitats include open deciduous woodland and wooded parkland and commons where they occur mostly on various oaks but occasionally other trees such as birch and alder. Mating occurs early in the year and, unusually among our UK members of the genus, females oviposit in galls of the sexual (winter) generation of the oak gall wasp Biorhiza pallida Linnaeus, 1758 (Hymenoptera, Cynipidae). Female weevils oviposit in April and May and are careful to search out suitable galls and many will be rejected, those chosen will have a diameter of 1.3-3.0cm and there will, presumably, be some sign to show whether the gall already contains a larva or eggs. Larvae feed on the internal gall tissue, out-competing the wasp larvae and so causing their death (they are sometimes quoted as eating the wasp larvae as well), they pass through three instars and are fully grown within three weeks, they then leave the gall and fall to the ground where they will form a subterranean cell in which to pupate. Larvae enter a diapause and most will go on to overwinter in the ground and pupate the following spring but at least some will pupate late in the year as adults have been recorded in December. Adult weevils are readily sampled by beating or sweeping oak foliage although they disperse by flight and also occur on other trees, most of our records are from sweeping birch in June.
Curculio villosus 1
Curculio villosus 2
© Lech Borowiec
Curculio villosus 3
© Lech Borowiec
Curculio villosus 4
3.8-5.0mm. Adults are quite distinctive from their general appearance and should not be confused with any other UK species. Body black, sometimes with the rostrum red about the middle, legs black or red but usually substantially dark with the tibial and femoral apices and tarsi lighter, antennae pale to dark red, forebody with elongate pale scales which often form a dense median line on the pronotum, elytra with similar scales that form a characteristic transverse band across the apical third. Head and pronotum densely and often confluently punctured. Eyes convex and continuous in outline with the short and diverging temples, rostrum long and curved, sometimes with scales around the base but mostly glabrous, antennae inserted beyond the middle in the male, behind the middle in the female, scape thickened just before the apex, funiculus 7-segmented and club 4-segmented and pointed. Pronotum broadest towards the base and evenly curved laterally fro rounded posterior angles to a slight constriction before acute anterior angles, surface variously scaled but often with a dense median longitudinal band. Scutellum elongate and densely scaled. Elytra with sloping shoulders and gradually narrowed to an acute apical margin, striae narrow, punctured and complete to the apex, interstices broad and transversely rugose, and the sutural interstice with dense scales in the apical third. All femora strongly toothed below.