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

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

of the family

Geometridae The geometer moths are moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyleti ...

. the species was first described by

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

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

Palearctic The Palearctic or Palaearctic is a biogeographic realm of the Earth, the largest of eight. Confined almost entirely to the Eastern Hemisphere, it stretches across Europe and Asia, north of the foothills of the Himalayas, and North Africa. Th ...

region and the

Near East The Near East () is a transcontinental region around the Eastern Mediterranean encompassing the historical Fertile Crescent, the Levant, Anatolia, Egypt, Mesopotamia, and coastal areas of the Arabian Peninsula. The term was invented in the 20th ...

. 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 opposite wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingsp ...

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

fascia A fascia (; : fasciae or fascias; adjective fascial; ) is a generic term for macroscopic membranous bodily structures. Fasciae are classified as superficial, visceral or deep, and further designated according to their anatomical location. ...

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 ''Aplocera efformata'', the lesser treble-bar, is a moth of the family Geometridae. The species was first described by Achille Guenée in 1858. It is known from Europe, Morocco and Anatolia. It has a wingspan of 35–41 mm. ''Aplocera effor ...

'' See Townsend et al. One or two broods are produced each year. In the

British Isles The British Isles are an archipelago in the Atlantic Ocean, 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 Hebrides, Inner and Outer Hebr ...

, 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 (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

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'' species).HOSTS database, National History Museum, London
Retrieved 2024 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