The geometer moths are belonging to the family Geometridae of the insect order Lepidoptera, the moths and butterflies. Their scientific name derives from the Ancient Greek geo γεω (derivative form of γῆ or γαῖα "the earth"), and metron μέτρον "measure" in reference to the way their larvae, or inchworms, appear to measure the earth as they move along in a looping fashion.
Caterpillars
The name "Geometridae" ultimately derives from Latin
geometra from Greek γεωμέτρης ("geometer", "earth-measurer"). This refers to the means of locomotion of the
or
, which lack the full complement of
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. The
cabbage looper and
soybean looper are not inchworms but caterpillars of a different family. In many species of geometer moths, the inchworms are about 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 are
gregarious and are generally smooth. Some eat lichen, flowers, or pollen, while some, such as the Hawaiian species of the genus
Eupithecia, are carnivorous. Certain destructive inchworm species are referred to as "cankerworms".
In 2019, the first geometrid caterpillar in Baltic amber was discovered by German scientists. Described under Eogeometer vadens, it measured about and was estimated to be 44 million years old, dating back to the Eocene epoch. It was described as the earliest evidence for the subfamily of Ennominae, particularly the tribe Boarmiini.
File:Looper.webm|thumbtime=0 |Locomotion of a looper
File:Geometridae-Dinakarr-10Jun11-DSC 0186.jpg|A geometrid caterpillar camouflaged as a broken twig
File:Geometridae locomotion.jpg|Caterpillar locomotion
File:Synchlora aerata caterpillar.jpg| Synchlora aerata caterpillar dressed with pieces of flowers as camouflage
Geometrid Moths (Geometridae) caterpillar -2.jpg|Geometrid moth (Geometridae) "inchworm" caterpillar
Geometrid Moths (Geometridae) caterpillar.jpg|Geometrid moth (Geometridae) "inchworm" caterpillar
Adults
Many geometrids have slender abdomens and broad wings which are usually held flat with the hindwings visible. As such, they appear rather
butterfly-like, but in most respects they are typical moths. The majority fly at night. They possess a frenulum to link the wings, and the antennae 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 and
fall cankerworm).
Most are of moderate size, about in wingspan, but a range of sizes occur, from , and a few (e.g.,
Dysphania species) reach an even larger size. They have distinctive paired
at the base of the abdomen (these are absent in flightless females).
File:Selenia tetralunaria MHNT ventre.jpg| Selenia tetralunaria species from Ennominae
File:Unidentified Moth 0752.jpg| Scopula species
File:Tetracis cachexiata 051712.jpg| Tetracis cachexiata in the US state of Ohio
File:Fall Cankerworm Moth - Alsophila pometaria, Leesylvania State Park, Woodbridge, Virginia.jpg| Alsophila pometaria, wingless adult female
Systematics
The placement of the example species follows a 1990 systematic treatment; it may be outdated. Subfamilies are tentatively sorted in a
phylogenetic sequence, from the most basal to the most advanced. Traditionally, the
Archiearinae were held to be the most ancient of the geometer moth lineages, as their
have well-developed
. However, it now seems that the
Larentiinae are actually older, as indicated by their numerous
and
DNA sequence data. They are either an extremely basal lineage of the Geometridae – together with the
Sterrhinae – or might even be considered a separate family of
Geometroidea. 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 an
atavism.
Larentiinae – about 5,800 species, includes the pug moths, mostly temperate, might be a distinct family.
Sterrhinae – about 2,800 species, mostly tropical, might belong to same family as the Larentiinae.
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Birch mocha, Cyclophora albipunctata
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False mocha, Cyclophora porata
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Maiden's blush, Cyclophora punctaria
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Riband wave, Idaea aversata
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Small fan-footed wave, Idaea biselata
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Single-dotted wave, Idaea dimidiata
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Small scallop, Idaea emarginata
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Idaea filicata
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Dwarf cream wave, Idaea fuscovenosa
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Rusty wave, Idaea inquinata
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Purple-bordered gold, Idaea muricata
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Bright wave, Idaea ochrata
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Least carpet, Idaea rusticata
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Small dusty wave, Idaea seriata
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Purple-barred yellow, Lythria cruentaria (formerly in Larentiinae)
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Vestal, Rhodometra sacraria
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Common pink-barred, Rhodostrophia vibicaria
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Middle lace border, Scopula decorata
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Cream wave, Scopula floslactata
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Small blood-vein, Scopula imitaria
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Lewes wave, Scopula immorata
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Lesser cream wave, Scopula immutata
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Mullein wave, Scopula marginepunctata
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Zachera moth, Chiasmia defixaria
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Blood-vein, Timandra comae
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Eastern blood-vein, Timandra griseata
Desmobathrinae – pantropical
Geometrinae – emerald moths, about 2,300 named species, most tropical
Archiearinae – twelve
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Infant, Archiearis infans (Möschler, 1862)
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Scarce infant, Leucobrephos brephoides (Walker, 1857)
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, tribe Boarmiini
Ennominae – about 9,700 species, including some defoliating pests, global distribution
Geometridae genera incertae sedis include:
Fossil Geometridae taxa include:
Further reading
External links
