Gypsy Moth Life Cycle
The adult female gypsy moth lays an egg mass in late summer, usually on vertical stable surfaces like tree trunks and building walls. At first, the egg mass is dark tan in color, but often bleaches to become more off white as the season progresses. The mass begins with a smooth texture, which usually erodes and by spring it looks weathered. The egg mass contains up to about 1,000 eggs, each producing a larvae. The eggs are very hardy, withstanding very cold temperatures and prolonged drying. Even if scraped onto the ground, nearly all will still hatch.
Both male and female caterpillars eventually turn into pupa where they metamorphose into adults. The first part of this process is when they spin a rough web of silk to secure them onto a surface. The body then contracts and the skin is eventually shed.
Multiple egg masses on a tree trunk. When infestation is high, several hundred egg masses can be laid on a single tree. Large, robust egg masses represent a healthy, well-fed gypsy moth population.
A well-developed pupal case. Feeding has stopped at this point, but adults are waiting to emerge and increase the population.
The gypsy moth eggs are subject to predation by a very small wasp species called Ooencyrtus kuvanae. This parasitoid burrows into the egg mass and lays its egg in the gypsy moth egg. The Ooencyrtus larvae consumes the gypsy moth egg and emerges as an adult.