Henosepilachna argus (Geoffroy, 1785)
POLYPHAGA Emery, 1886
CUCUJOIDEA Latreille, 1802
EPILACHNINAE Mulsant, 1846
Henosepilachna Li, 1961
This species was first recorded in the UK in 1997 from West Moseley in Surrey and is now widespread around London as well as sporadically further afield e.g. from the West Midlands and southwest Wales. Adults occur year-round, they overwinter among litter or low foliage and are active over a long season from March or April, typical habitats are gardens, waste ground and allotments but recently they have been widely recorded from more natural sites, especially from grassland on sandy or chalky soils. The UK host is white bryony, Bryonia alb L., a perennial climbing vine that is toxic to humans, while other members of this genus as well as cultivated melons are known to host the species in Europe. Mating occurs in May and June and females lay batches of eggs beneath host foliage. Larvae feed by scraping away the epidermis from both surfaces and may skeletonize entire plants in the process; they pass through three instars and develop rapidly, becoming fully-grown within six weeks. Mature larvae are very distinctive; pale greenish-yellow with one lateral and four dorsal rows of long dark spines with numerous pale and dark branched spines along their length. The pupa is equally distinctive; pale creamy or yellow with two rows of larger dark spots and numerous smaller dark spots, globular and with fine erect pubescence, the apical half retains the very distinctive last instar larval skin around the base. Pupae are usually attached to the upper or lower leaf surface but they have also been found on the ground, and they often occur side by side in pairs or small groups. New generation adults appear from late July and will feed until September or October when they will move to overwintering quarters. Adults are usually present early in the spring and may be swept from shrubs and low foliage in the vicinity of emerging host plants, they usually occur in numbers and are sometimes attracted to flowers or blossom, they fly well and so may suddenly appear wherever the host plants are common. The species is very likely to spread rapidly across the south (at least) and this northward spread from the continent is thought to be due to global warming.
5-7 mm. Distinctive among our ladybirds due to the large size, pubescent dorsal surface and characteristic colour; orange with five discrete black spots to each elytron and a another common to both below the scutellum, very rarely some of these spots may be fused but the large size and pubescence are distinctive.
Henosepilachna Li, 1961
At least 114 species of Henosepilachna have been described, about a fifth of all epilachnid species, although the genus is gradually being split and so this is likely to change. They occur throughout Europe, Asia, Australasia and Africa. All adults and larvae are phytophagous and many are classed as pests of cultivated corps, more especially of curcubitaceae. All species are pubescent and many are rather large for ladybirds, those in temperate regions tend to be orange with black markings but those in tropical regions are much more colourful. They are compact broadly-oval, cordate or elongate-oval ladybirds, the elytra are usually narrowly explanate but with very wide epipleura, especially in the basal half, which are flat or slightly angled down and entire; without depressions or grooves to accommodate the legs, and most species are continuous in outline and strongly convex. The head is partially retracted into the thorax so that the posterior margin of the eyes is hidden, the eyes are weakly convex, curved and finely faceted and the antennae have a loose 3-segmented club. The palps are weakly securiform and inserted medially on the labium and the mandibles are toothed in the apical half but not at the base. The prosternal process is narrow and either truncate or narrowly rounded below the front coxae. Legs short and robust with slender tibiae almost as long as the femora and trocanter combined and which have longitudinal grooves for the reception of the tarsi. Fore-tibiae with one or two large and acuminate spurs on the inner apical margin, middle and hind tibiae with two apical spurs. The tribe (which includes the UK species Subcoccinella vigintiquattuorpunctata (L.)), is characterized by the complex structure of the mandibles which are adapted to phytophagy. Larvae are typical of the subfamily with long, branched spines on the dorsal and lateral surfaces.
The Curcubit ladybird, H. bifasciata (Fabricius, 1775), is widespread across South Africa and Australasia and is sometimes a serious pest of cucumbers, especially the South African Spiny Cucumber. The Large Leaf-Eating Ladybird, H. guttatopustulata (Fabricius, 1775), from Australasia is a pest of solonaceae and a vector for Solanum nodiflorum mottle virus. H. curcubitae (Richards, 1983) occurs throughout Australia and New Zealand and is a pest of curcubits in general. Like many ladybirds some species have increased their range recently due to commerce and travel e.g. H. vigintioctopunctata (Fabricius, 1775), the 28-Spotted Potato Ladybird, which can be a serious pest of various Curcubitaceae and Solonaceae, was originally restricted to eastern Russia but is now widespread across China, Japan and Korea and has recently been recorded from New Zealand. At least 3 species occur in Europe and one of these, H. argus (Geoffroy, 1785), has recently been added to the British list. The Melon Ladybird, H. elaterii (Rossi, 1794, occurs extensively across southern Europe, western Asia and Africa where it can be a serious pest of the squirting cucumber Ecballium elaterium. Superficially similar to H. argus in colour and size, it can be separated by reference to the dark elytral spot below the scutellum; in elaterii they are well separated whereas in argus they lie on the sutural margin and so form a single large spot.