''Rhyzobius lophanthae'', commonly known as the purple scale predator or the scale-eating ladybird, is a species of ladybird native to

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

and Southern Australia. It was introduced into the United States in the 1890s and has since spread over the southern half of the country.

Taxonomy

This insect was first described in California in 1892 by the American entomologist Frank Ellsworth Blaisdell. He named it ''Scymnus lophanthae'', and thought it was a native American species. Unbeknown to him, the beetle was an introduced species, and at about the same time, it was described in its native Australia by the Australian entomologist Thomas Blackburn, who gave it the name ''Rhizobius toowoombae''. However, Blaisdell's name took precedence as it was published first, and ''R. toowoombae'' became a synonym. The specific name ''lophanthae'' means "of lophantha", referring to the plant ''

Paraserianthes lophantha ''Paraserianthes lophantha'' (syn. ''Albizia lophantha''), the Cape Leeuwin wattle, Bicol wattle, Cape wattle, crested wattle or plume albizia, is a fast-growing tree with creamy-yellow, bottlebrush like flowers. It is a small tree (uppermost hei ...

'' on which Blaisdell originally saw the ladybird.

Description

''Rhyzobius lophanthae'' is a small ladybird with a length between and a width of between . The head and

prothorax The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum ( dorsal), the prosternum ( ventral), and the propleuron ( lateral) o ...

are reddish-brown, as is the underside, both being densely covered with short hairs of two lengths. The

elytra An elytron (; ; , ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometimes alterna ...

(wing cases) are blackish, often with a metallic bronze sheen. The larvae are dark brown and is clad in stout spines.

Distribution and habitat

''Rhyzobius lophanthae'' is native to Australia where it is present in

and Southern Australia. It was introduced into California in 1892 in an attempt to control the olive scale ('' Saissetia oleae''). It has since spread over much of the southern United States. It can also be found in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

Ecology

Both adults and larvae feed on

scale insects Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than t ...

, and especially on armoured scales at all periods of their development; they also feed on mealybugs. The younger beetle larvae crawl under the adult scale insect's protective scale, feeding on the scale nymphs before they disperse. These insects are a pest of

citrus ''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is native to ...

, sucking the sap from the plants, and the ladybirds have been used in biological pest control, in order to reduce the number of scale insects in the crop.

References

* * {{Taxonbar, from=Q14930915 Coccinellidae Beetles described in 1892