Nargus wilkinii (Spence, 1813)

This widespread European species is generally common from the Pyrenees into central regions but rare and sporadic in the east, extending as far as Poland and Latvia, it has only rarely been recorded from Spain and Portugal but there is some evidence that it may be expanding there, to the south it extends into Italy and the Balkans and to the north to the UK and some southern provinces of Fennoscandia where it is mostly coastal. In the UK it is locally common across England and Wales though less so in the West Country and the north, and there are scattered records from Scotland and Ireland. Adults are present throughout the year and are active in all but the coldest winter spells, they peak in abundance from March to May and again in September and October, and are much less common (or active) during July and August. Typical habitats are open woodland and mature wooded parkland where adults may be sieved from accumulated leaf-litter and other organic debris but they occasionally occur among detritus in tree hollows and among decaying fungi etc. They are also associated with avian nests and mammal burrows, mostly those of rabbit and badger, although this association is not so strong as with some other members of the tribe e.g. Catops tristis (Panzer, 1794). Little is known of the biology but we have recorded the species from an old Jay nest during the winter in South Herts. and so the overwintering sites may be varied and not necessarily associated with mammal burrows, and the phenology would suggest a spring breeder with new-generation adults appearing in late summer. Adults are sampled by sieving old leaf-litter and here they may occur in numbers, they are also likely to appear in suitable extraction samples at any time.