Treble-bar
Encyclopedia
The Treble-bar or St. John's Wort Inchworm (Aplocera plagiata) is a moth
of the family Geometridae. It is found throughout the Palearctic
region and the Near East
.
This species varies considerably in size (wingspan
37–43 mm) and colouration but is generally grey with three characteristic dark fascia
across each forewing, giving it its common name. The hindwings are pale grey or buff. One or two broods are produced each year and the adults can be seen at any time from May to September. The species flies at night and is attracted to light.
The larva
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
. The species overwinters as a small larva.
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
of the family Geometridae. It is found throughout the Palearctic
Palearctic
The Palearctic or Palaearctic is one of the eight ecozones dividing the Earth's surface.Physically, the Palearctic is the largest ecozone...
region and the Near East
Near East
The Near East is a geographical term that covers different countries for geographers, archeologists, and historians, on the one hand, and for political scientists, economists, and journalists, on the other...
.
This species varies considerably in size (wingspan
Wingspan
The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...
37–43 mm) and colouration but is generally grey with three characteristic dark fascia
Fascia
A fascia is a layer of fibrous tissue that permeates the human body. A fascia is a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding those structures together in much the same manner as plastic wrap can be used to hold the contents of sandwiches...
across each forewing, giving it its common name. The hindwings are pale grey or buff. One or two broods are produced each year and the adults can be seen at any time from May to September. The species flies at night and is attracted to light.
The larva
Larva
A larva 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...
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
Hypericum is a genus of about 400 species of flowering plants in the family Hypericaceae ....
. The species overwinters as a small larva.
- The flight season refers to the British IslesBritish IslesThe British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
. This may vary in other parts of the range.