Facts About Butterfly Eggs

By Steve Johnson
How do butterflies breed?

They may be small-winged insects, but butterflies are among the world’s most interesting members of the animal kingdom. They are found everywhere in the world and contain thousands of different species. Their sizes vary from less than half an inch long, to some species that can reach up to 10 inches long between wing tips. Lesser known about butterflies is information about their eggs.

Egg Formation

Butterflies breed as many animals do—eggs from the female insect are fertilized by sperm from the male. The female butterfly stores the male’s sperm in a bursa, or sac, until she is ready to lay eggs. Depending on the species, females lay eggs one at a time, in clusters, or in batches of hundreds. Butterflies lay an average of between 100 to 300 eggs, although some species may only lay a few dozen, others can lay as many as a thousand or more.

Physical Characteristics

Butterfly eggs vary in size—from about 1 to 3 mm in diameter. Their shapes can be oval or round, while their colors range in a variety of colors, including yellow, white or green, depending on the species, according to Enchanted Learning.

Early Egg Stage

Butterfly eggs are normally attached to a plant--usually the leaf--with a special fluid. This glue holds the eggs to the leaf in such a way that they cannot be separated without destroying the eggs. Small funnel-shaped openings called "micropiles" can be found on top of each egg. This is where water and air enter while the egg is developing. Each egg is surrounded by a chorion, a hard outer shell that protects the larva. Some shells have raised ribs.


A female butterfly lays a great number of eggs. They also take special care of their eggs. The eggs need to be kept warm and must have the appropriate moisture or they will either rot or dry out. Normally, the eggs are attached to the underside of a leaf so they are kept safe from predators. A big portion of these eggs will not hatch to become butterflies as there are a lot of predators in the different stages of their life cycle. Of the few hundred butterfly eggs laid, very few will reach adulthood.

Egg Development

Inside each egg, a yolk can be found that serves as nourishment for the developing larva. A butterfly egg hatches after three to eight days depending on temperature and season of the year. A change in the egg’s color before hatching is normally visible. After hatching, some caterpillars eat their own eggshells as their first meal but most of them eat parts of the plant that the eggs were laid on.

About the Author

Steve Johnson is an avid and passionate writer with more than five years of experience. He's written for several industries, including health, dating and Internet marketing, as well as for various websites. He holds a bachelor's degree from the University of Texas.