Cionus hortulanus (Geoffroy in Fourcroy, 1785)
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POLYPHAGA Emery, 1886
CURCULIONOIDEA Latreille, 1802
CURCULIONINAE Latreille, 1802
CIONINI Schönherr, 1825
Generally common across Southern and Central Europe but more local and scattered in the north, reaching the UK, Denmark and Southern Fennoscandia but otherwise absent from the Baltic countries, this species extends east through Ukraine, Asia Minor and Russia into Western Siberia. In the UK it is locally common Southern and Central England and Wales and widespread though very local in Northern Ireland. Typical habitats include open woodland, woodland borders, waste ground, roadsides and open grassland exposed to the sun, they sometimes occur beside stagnant ponds and ditches and may be common on chalk grassland. Adults are active from April until August or September and peak in abundance during May and June, they are sometimes recorded through the winter but this is rare. Host plants include various Scrophulariaceae, primarily Common Figwort (Scrophularia nodosa L.), Water Figwort (S. auriculata L.) and Common Mullein (Verbascum Thapsus L.), less so on other members of these genera and occasionally Buddleja and, at least in Europe, Water Mudwort (Limosella aquatica L.). Breeding occurs during late spring and early summer following a period of feeding on host foliage and mating pairs are easily spotted exposed on host leaves and stems, females lay small batches of eggs towards growing tips or under buds and this may continue over several days, moving about a single plant and exploring stems and shoots as they do so. Larvae emerge after a few days and soon begin to feed on tender leaves and unopened buds, they feed singly or in groups and are very conspicuous, resembling small bloated greyish slugs, and when a plant is badly infested they form groups on buds and terminal leaves and may work their way down, stripping leaves as they go. Larvae are fully grown within a few weeks and pupation occurs in pale brown cocoons about 5 mm in diameter exposed on stems and leaves (although they have also been observed falling to the ground to pupate), this stage lasts between 6 and 10 days and new-generation adults appear from July. Both adults and larvae are diurnal and with a little experience easy to find on host foliage, they usually occur in numbers when sweeping host material and often along with other members of the genus.
3.8-4.6mm. Very typical of the genus in form and overall colour, head and pronotum with extensive long and pale scales, elytra conspicuously tessellated, the overall colour pale grey to greenish or creamy, legs with pale scales throughout, these usually displaying an indistinct tessellated pattern. This pale overall colour will distinguish it from our two common species, C. scrophulariae and C. tuberculosus, and the form of the rostrum will separate it from the remaining species. Head much narrower between the eyes than the rostral base, eyes large and convex, comprising most of the head, rostrum long and slender, in lateral view distinctly tapering in the apical third. Pronotum broadest towards or at the base (varies, in the female usually less tapering in the basal half) and narrowed to a curved apical margin, basal margin strongly sinuate, surface densely punctured and uneven but usually mostly obscured by scales. Elytra gently curved from rounded shoulders to a continuous apical margin, much broader across the base than the base of the pronotum, with a large round patch of black scales in the basal half and towards the apex, these are bordered with pale scales that do not contrast with the rest of the elytra, even numbered interstices with more-or-less even pale scaling, odd-numbered interstices distinctly tessellated. Femora strongly toothed below, tibiae not, or hardy, expanded apically, claws connate. In males the rostrum is a little shorter than the head and pronotum combined and the antennae are inserted beyond the middle, in females the rostrum is at least as long as the head and pronotum and the antennae are inserted at or just in front of the middle. The only confusion might be with other ‘pale’ members of the genus but the tapering rostral apex is distinctive.