Orsodacne cerasi (Linnaeus, 1758)

Of widespread occurence throughout England and Wales north to north Yorkshire; records are sporadic with many centred around the Severn estuary and the Lodon and Essex areas. There are many large gaps and it may be interesting that there are no records from the New Forest and very few from the southern coastal, including the west country, counties in general. Typical habitat is deciduous or mixed woodland and the species may be locally common. Adults occur from March until late summer and are most readily recorded by sweeping or beating trees and shrubs in flower or by searching umbels or hogweed (Heracleum spondyleum) or cow parsley (Anthriscus sylvestris); once in the beating tray or sweep net the adults move slowly and are easily examined but when disturbed from flowers they will often drop and take flight so care is needed. Locally we have recorded them from Hawthorn (Crataegus) blossom below Cassiobury park and dog rose (Rosa caminia) flowers around the borders of West Herts golf course. They have also been recorded from the flowers of meadowsweet (Filipendula ulmaria), wild cherry (Prunus avium), plum (Prunus domesticum), rowan (Sorbus curcuparia) and lilac (Syringa vulgaris) among others. Adults feed within flowers on pollen and anthers but not on leaves, stems or petals Cox) and have previously been recorded as pests of pear and cherry trees by destroying flowers in the spring (Jolivet, 1948). There is a single generation each year and oviposition occurs during June and July, larval feeding site is not known but the morphology suggest they may be root feeders and that they overwinter, probably above ground (Cox, 1981). In an earlier work Balachowsky (1963) suggested that larvae may mine within leaf petioles of woody hosts.

4.5-8mm. very distinctive and unlikely to be confused with any other species. Elongate and parallel sided, usually convex but this varies. Generally entirely testaceous or with the head darker but the colour is very variable and Fowler mentions several varieties; var chlorotica Latr. is the typical testaceous form, in var lineola Lac. the underside, vertex, suture and lateral margins of the elytra are dark while in var glabrata F., which had not occured in Britain, the entire body is black with the antennae and legs fuscous. Head and pronotum shiny with fine puncturation (obvious at X10). Eyes entire; convex and prominent. Clypeus and lubrum produced in front of antennal insertions. Width across eyes slightly narrower than pronotum. Pronotum quadrate with sides smoothly rounded and strongly contracted in basal half, without lateral borders or teeth. Front angles obscure, hind angles acute, basal margin straight and finely bordered. Distinctly narrower than elytra. Scutellum triangular, finely punctured and bordered. Elytra with prominent shoulders, subparallel and widest behind middle, lateral margins finely bordered and not usually visible from above, smoothly rounded to apex. Surface dull when compared to pronotum, randomly punctured and very finely pubescent, usually appearing glabrous. Legs testaceous. Tibiae gently sinuate with two small apical spurs on inside. Fourth tarsal segment bilobed, claw segment lon and narrow. All claws with a long tooth on inner side, sometimes these are as long as the claws which then appear double.

Description from 2 Watford specimens at X10

References
Balachowsky, A. 1963 Les insects nuisible aux plantes cultivees. 1 Coleoptera, 2, Paris
Cox, M.L. 1981 Notes on the biology of Orsodacne with a subfamily key to the larvae of the British Chrysomelidae. Entomologists Gazette 32:123-135
Jolivet, P. 1948 Les Orsodacnidae de la faune francaise. Miscrea ent. 95:33-46.

Home