Moths, Pacific Northwest
Inchworms are the larval or caterpillar stage of geometer moths, members of the Lepidoptera order of butterflies and moths. The Blackberry Looper is one of these.
They’re members of a very large family that includes over 26,000 species. About 1,200 of those species are native to North America.
The three names for this larval stage are looper, Inchworm and span-worm. All three names refer to the way in which the worm gets around.
It lacks the middle pair of legs that most caterpillars have. It therefore has just two sets of two or three legs at either end. So for example, it gets around by clasping the ground, leaf or stem with its front legs and moving its hind legs right behind them. Then the hind legs clasp the leaf and the front legs move forward, and so on.
Leaves are the most common food source. But there are some inchworm species that favor pollen, lichens or flowers.
There are even some that are carnivorous. There are even others that are far more destructive in their feeding, and they are called canker-worms. But whatever the type, they represent a particularly vulnerable stage within the geometer moth life cycle.
Specifically, larval stages tend to be attractive to such predators as birds and foraging mammals. So they are a much needed food source for birds and animals. When it’s disturbed or stressed, the inchworm clasps the surface with its hind legs and stands straight up and still.
The Blackberry Looper is quite common on Vancouver Island and we always run into it when we pick Blackberries, I am always surprised at just how fast they are able to move and at how, when they are alarmed and standing extended from a branch, how invisible they become.
They are a very pretty and quite a large inchworm to observe. They are able to eat a large amount of leaf material when feeding.