Gypsy Moth Life Cycle
This section presents information about the life cycle of gypsy moths.
Gypsy Moth Larva
Gypsy moth larva take the form of a caterpillar. They hatch in the spring from eggs laid the previous summer. They crawl up trees and out on the limbs and start eating tree leaves.
They start out small, but soon grow larger as they eat tree leaves. When small they are lightweight and buoyant. They suspend from trees on gossamer strands and get blown by the wind - sometimes for miles. This is one way they can be spread over wide areas.
As the caterpillars grow, they molt 5 times; each time shedding their previous skin. Each growth stage is called an instar. Females molt 6 times, and grow slightly larger than males. They can grow up to 2½ inches in length.
Transition To Pupa
When the caterpillars are full grown after about 2 months of eating leaves, they find a place to hide and transform into the pupal stage. The picture on the right shows a caterpillar in the process of turning into a pupa.
Gypsy Moth Pupa
A gypsy moth pupa is shown on the right. While in the pupal stage, they go through a transition called metamorphosis, and turn into a moth.
Male and Female Gypsy Moths
After less than a week's time, the male and female moths emerge from their respective pupa. The males are brown and fly. They flutter around seeking a female. The females are white in color and don't fly. They crawl someplace and wait for a male to find them and mate with them, such as is seen in this photo.
Female Laying Eggs
After being fertilized by the male, the female gypsy moth lays a mass of eggs. An egg mass can hold hundreds of eggs.
Egg Mass
The egg mass is kind of blob that will stick where it is deposited until next spring. When the eggs hatch there may be hundreds more gypsy moths.
Multiple Egg Masses
Numerous egg masses are being deposited on this tree. Next spring many hundreds of gypsy moth larvae will hatch and attack this poor tree.