Emerald Moth
At lights, upper Kerio Valley, Elgeyo-Marakwet, Kenya, Dec. 2014.
The characteristic locomotion of the immature stage, a larva (caterpillar), gives a common name for this group of moths. The wings of geometrids tend to be thin and fragile and generally held flat against the substrate when alighted; the adults are short-lived and don't feed as adults. Many geometrids also have exquisite camouflage patterns that make them virtually invisible when perched on natural substrates. The emerald moths, this subgroup of Geometridae, are safest when alighted on green foliage. At night they are among the many insects attracted to electric lights. Birds and other insect predators have learned that lots of easy prey can be had around lights.