Family Geometridae (Geometer moths) - Biodiversity (Singapore)

This is a very large family of nocturnal moths, of around 23,000 species. The family name Geometridae is derived from Latin geometra from ancient Greek geo γεω (derivative form of γῆ or γαῖα “the earth”), and metron μέτρον “measure” in reference to the way their inchworms larvae, appear to measure the earth in their typical manner. This is mainly the result of them lacking the usual five pairs of prolegs and only having two or three pairs at the posterior end.

In many species of geometer moths, the inchworms are about 25 mm long, usually green, grey, or brownish to hide from predators by fading into the background. Some species have protrusions or filaments or cover themselves in plant material to further their camouflage. Many inchworms, when disturbed, stand erect and motionless on their prolegs, increasing the resemblance to twigs. They feed on lichen, flowers, or pollen, while some are carnivorous.

Adult geometrids usually have slender abdomens and broad wings held flat against the perch surface with the hindwings visible. The disruptive coloration and patterned wings allow them to blend into the background. Most geometrids are moderately sized, ranging from 10–50 mm and a few Dysphania species for example reach an even larger size.