The geometer moths or Geometridae are a family of the order Lepidoptera. A very large family with around 26,000 species of moths described (over 300 of which occur in the British Isles), it notably includes the peppered moth, Biston betularia.
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 in to 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 3 cm across but a range of sizes occur. They have distinctive paired tympanal organs at the base of the abdomen (lacking in flightless females).
Caterpillars
Locomotion of the geometrid caterpillar
The name Geometer (earth-measurer) refers to the means of locomotion of the larvae or caterpillars, which lack most of the prolegs of other Lepidopteran caterpillars. Equipped with appendages at both ends of the body, a caterpillar will clasp with its front legs and draw up the hind end, then clasp with the hind end (prolegs) and reach out for a new front attachment - creating the impression that it is measuring its journey. The caterpillars are accordingly called loopers, spanworms, or inchworms. They tend to be green, grey, or brownish and hide from predators by fading into the background or resembling twigs. Some have humps or filaments (see Filament-bearer image). They are seldom hairy or gregarious. Typically they eat leaves. However, some eat lichen, flowers or pollen. Some, such as the Hawaiian species of the genus Eupithecia, are even carnivorous.
Species
Species include (organized as commonly agreed in 1990):
Archiearinae -- 12 species, Holarctic & south Andes & Tasmania. Larvae have all the prolegs except most are reduced.
Ennominae-- 9700 species, including some pest defoliators; global distribution
Oenochrominae -- includes some genera that are just difficult to place in other groups
Alsophilinae -- one genus, defoliators of trees
Desmobathrinae -- Pantropical
Geometrinae -- Emerald moths, 2300 named species, most tropical
Sterrhinae -- 2800 species, mostly tropical
Larentiinae-- 5700 species, mostly temperate
Pugs are included in Larentiinae:
See also
References
- Scoble, MJ (ed.) 1999. Geometrid Moths of the World: A Catalogue. CSIRO Publishing. ISBN 0-643-06304-8
- Minet, J and MJ Scoble. 1999 The Drepanoid / Geometroid Assemblage. Ch 17 in Kristensen, N.P. (Ed.). Lepidoptera, Moths and Butterflies. Volume 1: Evolution, Systematics, and Biogeography. Handbuch der Zoologie. Eine Naturgeschichte der Stämme des Tierreiches / Handbook of Zoology. A Natural History of the phyla of the Animal Kingdom. Band / Volume IV Arthropoda: Insecta Teilband / Part 35: 491 pp. Walter de Gruyter, Berlin, New York.
- Hausmann, A. 2001. The geometrid moths of Europe. v. 1. Introduction. Archiearinae, Orthostixinae, Desmobathrinae, Alsophilinae, Geometrinae -- v. 4. Larentiinae II (Perizomini and Eupitheciini). Apollo books.
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