The world is home to around 180,000 species of moths and butterflies, all of which go through a larval stage in their development, starting their lives as caterpillars after hatching from eggs.
With the exception of the salami-and-sausage-eating title character of The Very Hungry Caterpillar, the vast majority of the world’s caterpillars are vegetarians that feed on leaves and other vegetation. However, about 20 species of Eupithecia inchworms (the caterpillars of geometer moths) native to Hawaii are carnivorous and prey on flies, crickets, spiders, and cockroaches. Sometimes they even consume other caterpillars and adult moths.
The inchworms use camouflage to disguise themselves as twigs or leaves, lying in wait for bugs to land on them before ambushing their prey with the sharp, pincer-like ends of their legs. Rather than using sight or sound to find food, they rely on the sensitive hairs on their backs to alert them to the presence of prey. When an unsuspecting insect comes in contact with their hind end, their body swings into action and they quickly grasp the victim with their raptorial forelegs.
Biologists aren’t sure why less than two dozen of the approximately 1,400 species of geometer moths in the genus Eupithecia have developed a carnivorous diet. It is also a mystery why this strange evolutionary adaptation occurred in Hawaii but nowhere else.
A uniquely carnivorous caterpillar:
- The term “inchworm” refers to the larvae of moths in the Geometridae family, which contains 23,000 species. With the exception of the Hawaiian carnivores, all of these tiny green, brown, or tan caterpillars consume a plant-based diet.
- The order Lepidoptera contains both butterflies and moths. The 180,000 species in the order make up around 10% of the planet’s total described species of living organisms.
- Only about 18,000 of the 180,000 species in Lepidoptera are butterflies; the rest are moths.
