Apion frumentarium (Linnaeus, 1758)

This conspicuous and attractive species is generally common throughout Europe, except for the far north, southwest Asia and the Middle East; Turkey, Syria and Israel etc. Huge numbers, collected in Israel, have been released in Western Australia in the hope that they would become established as a biocontrol agent but this has so far been unsuccessful. In the U.K. it is common throughout England and Wales and very local in southern Scotland. Host plants include various Rumex species (docks) but especially R. hydrolapathum Huds., R. crispus L., R. obtusifolius L. and R. conglomeratus Murray, and the beetles may be found wherever they occur e.g. parks, gardens, waste ground and agricultural margins etc. Adults occur year round but are most obvious from April to July when they are active both on the hosts and also dispersing; at this time they may be seen on umbel flowers, and swept from long grass and nettles etc. Winter is passed low down in the stems or under debris and in tussocks and they may become active during warm spells when they may feed underneath Rumex leaves. They are active from early spring when they may be seen crawling on bare soil, especially on arable margins, and begin feeding on young host foliage producing small shot holes. Mating occurs from April and continues over a long period, at least into July. Females chew small holes into the stems and petioles in which they lay a single egg and seal the damage with a secretion, the larvae develop within the petioles, stems and roots, sometimes producing swellings or discoloured lines of dead epidermis as they go. They have a relatively long development period; about a month or so and pass through three instars before pupating, this stage lasts for five or six days and new generation adults appear from late May or June. They spend some time feeding before leaving the host to find summer aestivating sites, appearing again in late summer and autumn to continue feeding before heading for overwintering sites in October and November. In most years they will be seen through the winter on host foliage or on the ground near the host.