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The Scymnini are a tribe of insects within the family

Coccinellidae Coccinellidae () is a widespread family (biology), family of small beetles. They are commonly known as ladybugs in North America and ladybirds in the United Kingdom; "lady" refers to Mary, mother of Jesus, mother Mary. Entomologists use the ...

. This group includes many small species that are commonly known as dusky ladybugs.

Features

Adults

The adult beetles of Scymnini are small, typically one or two millimeters long. Their body is hemispherically domed and is almost always covered with dense hair. Only a few species have a smooth and glossy back surface. Many species can be identified by their characteristic pattern and their size, however examination under a

microscope A microscope () is a laboratory equipment, laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic ...

is usually needed. The Scymnini like the Chilocorini show their head well below the prothorax (pronotum). Their very short probes are built differently and have a reduced number of members. The Chilocorini differ from the Scymnini by their greatly expanded endplates ( clypeus ).

Larvae

The larvae of Scymnini secrete a white, waxy substance, which their body is covered with. Exceptions are only seen in the species of the genus Stethorus who have no such guard formations. On the other hand, there are wax coatings also in the larvae of other tribes of ladybugs, z. B. in Coccidulini and Chilocorini. The larvae have also been known for forming small congregations of their own species, leaving a white smudge on the surface they are on.

Life style and distribution

The species of the tribe Scymnini are distributed worldwide. They feed on

spider mites Spider mites are members of the family Tetranychidae, which includes about 1,200 species. They are part of the subclass Acari (mites). Spider mites generally live on the undersides of leaves of plants, where they may spin protective silk webs, a ...

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 the ...

, Aledyrodoid moths and

aphids Aphids are small sap-sucking insects in the Taxonomic rank, family Aphididae. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white Eriosomatinae, woolly ...

. The beetles lay their eggs on leaves, which are infested with the lice or mites. These are not only predatory as adults but also as larvae.

Systematics

The Scymnini were nomenclatured for a long time under the name Scymninae as one of numerous subfamilies of ladybugs. In 2007 was Adam Ślipiński proposed a new system, which contains only two subfamilies. Under that system, the Scymnini belong to the subfamily as Tribe Coccinellinae. The internal and external classification of Scymnini within this new subfamily needs to be investigated in more detail. Preliminary molecular studies have shown that the family is probably

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

References

Adam Ślipiński: ''Australian Ladybird Beetles (Coleoptera: Coccinellidae) their Biology and Classification.'' ABRS, Australian Biological Resources Study, Canberra 2007

Bernhard Bernhard is both a given name and a surname. Notable people with the name include: Given name *Bernhard of Saxe-Weimar (1604–1639), Duke of Saxe-Weimar *Bernhard, Prince of Saxe-Meiningen (1901–1984), head of the House of Saxe-Meiningen 1946 ...