Looper caterpillars inch along
Looper caterpillars belong to one of the largest families of moths and butterflies; there are at least 35,000 species.
The Greek name for this group is Geometridae, which in simple terms means "earth measurer".
They are also called inch worms and span worms, names that describe their method of locomotion.
Caterpillars of other moth and butterfly families have five pairs of short, stubby appendages called pro-legs at the rear of the body. Loopers have only two or three pairs but they do have clasping front legs.
In this photograph, the looper is reaching forward with its body to grasp the next capsule of the kowhai seed on which it is crawling. The front legs are clearly seen. When it has a secure hold, it will release its pro-legs at the back and draw its body into a loop before repeating the process. So they move along in a series of loops.
Loopers tend to be green, grey or brown, colours that usually match the foliage on which they are feeding. When disturbed they will often stand erect on their pro-legs and so seek to hide from predators by resembling a twig.
These caterpillars feed on the foliage of a wide variety of plants. Usually they feed unnoticed but occasionally they can reach plague proportions in our forests and cause severe defoliation and retard growth.
A looper caterpillar feeds for around two weeks before changing into a pupa from which an adult night-flying moth will emerge some 10 days later.
The Southland Times