Nephus quadrimaculatus (Herbst, 1783)
POLYPHAGA Emery, 1886
CUCUJOIDEA Latreille, 1802
COCCIDULINAE Mulsant, 1846
Nephus Mulsant, 1846
This locally common species occurs from lowland to low mountain altitudes throughout Europe north to the UK and southern provinces of Fennoscandia and extending east to Ukraine and the western borders of Russia. It was formerly considered very local and rare in the UK with most records centred around East Anglia but over recent decades it seems to have increased in both range and abundance; it is now generally common in the Home Counties, across East Anglia and along the Welsh border and there are scattered records north to Leeds although it remains absent from most of the south west. The species is strongly associated with ivy but may also occur on various broadleaf trees such as alder, beech and sycamore, and on the continent, where it is sometimes abundant in olive groves, it has been recorded from a very wide range of broadleaf trees and shrubs. Adults fly well and disperse during hot summer days and so might be found in a wide range of habitats but they typically occur in open woodland, parkland and gardens, and they may also occur in numbers among ivy growing on garden walls etc. Adults are present year-round, they overwinter under bark or in bark crevices and become active very early in the year, during January or February depending upon the season, they peak in abundance during late March/early April and again during August and mating pairs may be found through the spring and late into the summer. Both adults and larvae predate various scale insects, aphids and other small insects and their early stages, it is likely that larvae develop exclusively on ivy and hunt their prey exposed on stems and leaves. Adults may be encountered when sweeping broadleaf trees that are infested with scale insects, they also tend to turn up when sweeping generally, but they are easily sampled by beating ivy, they will usually occur in numbers over a very long season but might also be found during the winter when they sometimes become active during mild spells and may be recorded from ivy flowers and stems.
Nephus quadrimaculatus 1
© Lech Borowiec
Nephus quadrimaculatus 2
Adults may be recognized by their small size, 1.5-2.0mm, pubescent dorsal surface and characteristically patterned elytra. Head and pronotum black, sometimes with the labrum and a narrow anterior margin of the pronotum obscurely reddish, elytra black with four orange markings; the anterior pair oblique, reniform and larger than the posterior pair. Legs substantially red, the outer margin of the tibiae and the claws often dark grey, and the antennae are orange or darkened towards the clubs.
The Ant-nest ladybird (Platynaspis luteorubra (Goeze, 1777)) is superficially similar but always larger, 2.5-3.5mm, and has the head and lateral margins of the pronotum pale. Some maculate species of Scymnus may also be similar but in all cases they differ in the fine detail of the elytral markings, doubtful specimens can be distinguished by the form of the tarsi and prosternum; in Scymnus the tarsi are 4-segmented and the prosternum is keeled whereas in Nephus the tarsi are 3-segmented and the prosternum is smooth.