Chaetocnema concinna (Marsham, 1802)
Mangold flea beetle

This species is generally common over much of the Palaearctic region from Europe to the far east of Russia, China, Japan, Korea and Taiwan; it is widespread in Europe north to the Arctic Circle and occurs in North Africa and on most of the Mediterranean islands. The first record from North America was from Massachusetts in 1979 and since that time it has been found to be widespread in the north east and adjacent parts of Canada and it has been recorded further afield, from Texas and Oregon. In the UK it is common throughout England and Wales, including all the islands, and it occurs across southern Scotland and Northern Ireland but, apart from occasional records from the Highlands, appears to be absent further north. Adults are present year-round; they overwinter in grass tussocks or among decaying vegetation and are active from April until October, peaking in abundance during May and June. Habitats include grassland, wetland margins, arable land, woodland, dunes and beaches, saltmarshes and disturbed areas such as gardens, roadsides and allotments, but the species flies well and during the warmer months might be found in just about any situation. On the continent it has been recorded up to 2300 m. Adults have been recorded feeding on a wide range of foliage including various Polygonaceae such as Sheep’s Sorrel (Rumex acetosella L.), Common Sorrel (R. acetosa L.), Buckwheat (Fagopyrum esculentum Moench), Black Bindweed (Fallopia convolvulus (L.)) and Chinese Rhubarb (Rheum palmatum L.) and they may also be pollen feeders as they often appear in numbers on hawthorn blossom in the spring. Host plants also include a wide range of Polygonaceae but plants from ten or so families have been recorded hosting the species e.g. Fat Hen (Chenopodium album L. Amaranthaceae), orach (Atriplex L. Chenopodioideae), Lesser Periwinkle (Vinca minor L. Apocunaceae) and various beets (Beta L.) where the species is an occasional pest of commercially grown cultivars. Mating occurs after a period of feeding in the spring and oviposition begins in May and continues into July. Eggs are laid in small batches in the soil below host plants and larvae mine fine galleries in the roots, they pass through three instars and are fully developed within about four weeks. Larvae pupate among the roots from July until September and the first new-generation adults usually appear from July. There is a single generation each year. Adults can be sampled by general sweeping; they also occur on low foliage of a range of trees and will often appear in flight-interception traps. Adults produce numerous small round holes in foliage as they feed and these may be a clue as to the presence and local abundance of the species.