| Geometer moth | |
|---|---|
 | |
| Chiasmia species fromEnnominae | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Lepidoptera |
| Superfamily: | Geometroidea |
| Family: | Geometridae Leach, 1815 |
| Subfamilies | |
| |
Thegeometer moths aremoths belonging to thefamilyGeometridae of the insectorderLepidoptera, the moths and butterflies. Their scientific name derives from the Ancient Greekgeoγεω (derivative form ofγῆ orγαῖα "the earth"), andmetronμέτρον "measure" in reference to the way their larvae, orinchworms, appear to measure the earth as they move along in a looping fashion.[1] Geometridae is a very large family, containing around 23,000 described species;[2][3] over 1400 species from six subfamilies are indigenous to North America alone.[1] A well-known member is thepeppered moth,Biston betularia, which has been the subject of numerous studies inpopulation genetics. Several other geometer moths are notoriouspests.
The name "Geometridae" ultimately derives from Latingeometra from Greekγεωμέτρης ("geometer", "earth-measurer"). This refers to the means of locomotion of thelarvae orcaterpillars, which lack the full complement ofprolegs seen in other caterpillars, with only two or three pairs at the posterior end instead of the usual five pairs. Equipped with appendages at both ends of the body, a caterpillar clasps with its front legs and draws up the hind end, then clasps with the hind end (prolegs) and reaches out for a new front attachment, creating the impression that it measures its journey. The caterpillars are accordingly called "loopers", "spanworms", or "inchworms" after their characteristic looping gait. Thecabbage looper andsoybean looper are not inchworms but caterpillars of a different family. In many species of geometer moths, the inchworms are about 25 mm (1.0 in) long. They tend to be green, grey, or brownish and hide from predators by fading into the background or resembling twigs. When disturbed, many inchworms stand erect and motionless on their prolegs, further increasing this resemblance. Some have humps or filaments, or cover themselves in plant material. They aregregarious and are generally smooth. Some eat lichen, flowers, or pollen, while some, such as the Hawaiian species of the genusEupithecia, are carnivorous. Certain destructive inchworm species are referred to as "cankerworms".[4]
In 2019, the first geometrid caterpillar inBaltic amber was discovered by German scientists. Described underEogeometer vadens, it measured about 5 mm (0.20 in) and was estimated to be 44 million years old, dating back to theEoceneepoch. It was described as the earliest evidence for the subfamily ofEnnominae, particularly the tribeBoarmiini.[5]
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Many geometrids have slenderabdomens and broad wings which are usually held flat with the hindwings visible. As such, they appear ratherbutterfly-like, but in most respects they are typical moths. The majority fly at night. They possess afrenulum to link the wings, and theantennae of the males are often feathered. They tend to blend into the background, often with intricate, wavy patterns on their wings. In some species, females have reduced wings (e.g.winter moth andfall cankerworm).[1] Most are of moderate size, about 3 cm (1.2 in) in wingspan, but a range of sizes occur, from 10–50 mm (0.39–1.97 in), and a few (e.g.,Dysphania species) reach an even larger size. They have distinctive pairedtympanal organs at the base of the abdomen (these are absent in flightless females).[citation needed]
The placement of the example species follows a 1990 systematic treatment; it may be outdated. Subfamilies are tentatively sorted in aphylogenetic sequence, from the mostbasal to the most advanced. Traditionally, theArchiearinae were held to be the most ancient of the geometer moth lineages, as theircaterpillars have well-developedprolegs. However, it now seems that theLarentiinae are actually older, as indicated by their numerousplesiomorphies andDNA sequence data. They are either an extremelybasal lineage of the Geometridae – together with theSterrhinae – or might even be considered a separatefamily ofGeometroidea. As regards the Archiearinae, some species that were traditionally placed therein actually seem to belong to other subfamilies; altogether it seems that in a few cases, the prolegs which were originally lost in the ancestral geometer moths re-evolved as anatavism.[6][7]
Larentiinae – about 5,800 species, includes the pug moths, mostly temperate, might be a distinct family.[6][7]
Sterrhinae – about 2,800 species, mostly tropical, might belong to same family as the Larentiinae.[6]
Desmobathrinae – pantropical
Geometrinae – emerald moths, about 2,300 named species, most tropical
Archiearinae – twelve[8] species; holarctic, southern Andes and Tasmania, though the latter some seem to belong to the Ennominae,[7] larvae have all the prolegs but most are reduced.
Oenochrominae – in some treatments used as a "wastebin taxon" for genera that are difficult to place in other groups
Alsophilinae – a few genera, defoliators of trees, might belong in the Ennominae,tribeBoarmiini[7]
Ennominae – about 9,700 species, including some defoliating pests, global distribution
Geometridae generaincertae sedis include:
Fossil Geometridae taxa include:
