Cankerworms belong to a
group of insects known as inchworms and loopers. There
is a species that feeds in late spring (Paleacrata
vernata) and another that does its damage in fall of
the year (Alsophila pometaria).
These insects are members
of the Family Lepodoptera along with all the
butterflies and moths. They have legs at the front and
back of their bodies but none in the middle. So, they
creep along by grabbing hold with the front legs and the
allowing the back legs to move forward. This forms the
"loop" that is characteristic of this group of insect
As with the
the male adult cankerworm can fly but the female cannot.
In fact, she is wingless and must stay near where she
emerges from her pupal case. In late spring, the male is
attracted to her by a strong pheromone, they mate and
then she lays eggs on the bark and twigs.
The fall cankerworm goes
through the same cycle except that they lay their eggs
in October or later.