The treble-bar or St. John's wort inchworm (''Aplocera plagiata'') is a

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

of the family Geometridae. the species was first described by

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in his 1758 10th edition of ''Systema Naturae''. It is found throughout the

Palearctic The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Sibe ...

region and the

Near East The ''Near East''; he, המזרח הקרוב; arc, ܕܢܚܐ ܩܪܒ; fa, خاور نزدیک, Xāvar-e nazdik; tr, Yakın Doğu is a geographical term which roughly encompasses a transcontinental region in Western Asia, that was once the hist ...

. This species varies considerably in size (

wingspan The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the other wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingspan of ...

37–43 mm) and colouration but is generally grey with three characteristic dark

fascia A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal organs. ...

across each forewing, giving it its common name. The hindwings are pale grey or buff. Many forma have been described. See Prout (1912–16) ''Aplocera plagiata'' is difficult to certainly distinguish from its congener '' Aplocera efformata'' See Townsend et al.Martin C. Townsend, Jon Clifton and Brian Goodey (2010)
''British and Irish Moths: An Illustrated Guide to Selected Difficult Species''
(covering the use of genitalia characters and other features) Butterfly Conservation. One or two broods are produced each year. In the

British Isles The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, ...

, the adults can be seen at any time from May to September. The species flies at night and is attracted to light. The egg is whitish, without gloss, micropylar rosette 11- to 12-leaved, the sides with regular polygonal reticulation, each cell again more irregularly subdivided. The

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

is also very variable, being green to reddish brown with alternating darker and lighter stripes. It feeds on various species of

St John's wort ''Hypericum perforatum'', known as St. John's wort, is a flowering plant in the family Hypericaceae and the type species of the genus ''Hypericum''. Possibly a hybrid between '' H. maculatum'' and '' H. attenuatum'', the species can be found a ...

(''Hypericum'' species). It overwinters as a small larva.

Subspecies

*''Aplocera plagiata hausmanni'' *''Aplocera plagiata plagiata''

References

*Chinery, Michael ''Collins Guide to the Insects of Britain and Western Europe'' 1986 (Reprinted 1991) *Skinner, Bernard ''Colour Identification Guide to Moths of the British Isles'' 1984

External links

Treble-bar at ''UKMoths''''Fauna Europaea''''Lepiforum e.V.''
{{Taxonbar, from=Q1415385 Aplocera Moths described in 1758 Moths of Europe Moths of Asia Taxa named by Carl Linnaeus