Chilocorus bipustulatus (Linnaeus, 1758)
POLYPHAGA Emery, 1886
CUCUJOIDEA Latreille, 1802
CHILOCORINAE Mulsant, 1846
Chilocorus Leach, 1815
Native to the Palaearctic region and occurring from Europe to the far east of Siberia, this species is now established in many countries throughout the world through being introduced to many regions as a biocontrol agent of various plant parasites. It is widespread and generally common across Europe north to the UK and central provinces of Fennoscandia, it occurs in North Africa and Asia Minor and is recorded from the Mediterranean and Atlantic islands, in the UK it is common across southern and central England, and more local further north to the Scottish border and across Ireland although it appears to be spreading northwards into Scotland. This very distinctive species is typical of heather moorland, heathland, scrub and coastal dunes but it may also be found in a very wide range of habitats; it often occurs on conifer trees in parks and gardens and, in the summer also on deciduous trees such as willow and beech, it may be swept from various shrubs, bramble, gorse and broom, and in Europe it is often common in pine forests, orchards and quarries. Adults and larvae are specialist predators of scale insects; both soft bodied (Coccidae) and armoured scales (Diaspididae), but they readily predate aphids and other small insects and have been quoted as feeding mostly on larvae of the heather leaf beetle (Lochmaea suturalis (Thomson, C.G., 1866)) although this is probably based on local observations as like all members of the genus they have mandibles (among other adaptations) modified to feeding on armoured scale insects that live under waxy defensive secretions. Adults are present year-round, they overwinter under bark or among litter and become active early in the year although they are often active during mild winter spells as well, they mate over a long spring and early summer period and are thought to be univoltine in temperate northern regions, this may vary further south and in tropical regions they are known to be continuously-breeding with up to six generations each year. Eggs are attached to foliage, usually on the underside and not always on heather, and larvae emerge after a few days, they are active predators and are easy to see and identify on leaves and stems; the final instar is mainly dark brown but has a distinctive pale basal abdominal segment, each abdominal and thoracic segment has six long branched spines, these are black except for those on the base of the abdomen which are pale, earlier instars are extensively pinkish-grey with black spines. They pupate exposed on leaves and stems; the pupa is shiny black but usually shrouded in the larval skin
Chilocorus bipustulatus 1
Chilocorus bipustulatus 2
Chilocorus bipustulatus 3
© Lech Borowiec
which retains its colour and so the pupa can easily be identified. Teneral adults, which can be identified by their paler colour and soft body, appear through the summer. Among the numerous insects predated by the heather ladybird, the following notorious pest species have been subjected to biological control in various parts of the world: the olive scale insect (Saissetia loeae (Olivier, 1971), one of the main pests of olive and citrus trees in southern Europe, Aspidiotus nerii Bouché, 1833, an armoured scale insect pest of a wide range of crops, Chionaspis salicis (Linnaeus, 1758,) a widely polyphagous armoured scale insect, Florida red scale, Chrysomphalus aonidum (Linnaeus, 1758), an armoured scale insect common in northern temperate regions, Mulberry scale (Pseudaulacaspis pentagona (Targioni Tozzetti, 1886) and Citrus mealybug (Planococcus citri Risso, 1813). In truth the species is highly adaptable and will predate most small insects on a wide range of trees and shrubs, its northern limit is restricted by cold winters but otherwise it might be expected in any situation with heather or plenty of trees and shrubs. Adults are easily sampled by sweeping but they usually occur in small numbers and, away from heather or conifers, often along with other coccinellids.
3-4 mm. Almost circular in outline and very convex, entirely shiny black with three red spots arranged transversely across the elytra, these may be variously united but there are no other colour varieties, underside, legs and antennae reddish-brown. Dorsal surface very finely punctured. Head transverse and very strongly widened anteriorly, antennae 8-segmented, inserted under the clypeal plate so usually not visible. Pronotum widely transverse, rounded laterally and with projecting anterior angles, explanate margin narrow and basal margin smoothly curved. Elytra almost circular, broader across the slightly-produced shoulders than the widest part of the pronotum, laterally steep sided and hardly explanate, epipleura broad almost to the apex, medially reflexed under the middle and hind femora. Front femora expanded externally from a tooth towards the base, Claws distinctly toothed at the base.