The Spittle Bug

Forrest M. Mims III

A carpet of green plants and flowers accompanies spring in temperate zones. Look carefully in the greenery, and you will probably find evidence of spittle bugs (family Cercopidae).

When they are young nymphs, they live inside a cluster of glistening bubbles that originally came from the sap inside the plant now hosting the bubbles.

The nymph hatched from an egg laid the previous year. It then crawled up a convenient plant stem and poked its mouth into the stem. The nymph secreted a sticky fluid made from the sap. It then whipped the fluid into bubbles.

Its bubble house is supposed to protect the spittle bug from its enemies. After all, when it is hiding inside, it cannot be seen.

There may be more to this story, for the bubbles advertise the presence of the spittle bug. Perhaps potential enemies do not want to become clogged up in bubbles just to enjoy a meal.

Besides protecting the nymph, the bubble house stabilizes its temperature. The air inside the bubbles serves as an insulator that keeps the nymph inside at a fairly stable temperature during cool spring nights and a warm spring days.

The bubble house might be damaged by excessive heat. Therefore, the spittle bug usually builds its bubble house below a canopy of leaves that provide shade.

A third purpose of the spittle is to keep the spittle bug moist. It will die it its body dries.

Like various insects, the nymph goes through various stages before becoming an adult. These stages are called instars, and the spittle bug goes through five of them.

By the time the nymph matures into an adult spittle bug, it has developed wings and strong jumping legs. It then leaves its bubble house and begins a completely new life.

The most amazing fact about the spittle bug is not the bubble house it grew up inside but its incredibly powerful jumping legs. The froghopper, which is the name for one kind of adult spittle bug, can propel itself with a force 400 greater than that of gravity! If you or I experienced an acceleration of around five times gravity, we would probably faint.

The froghopper's amazing jumping ability is made possible by a pair of huge muscles that take more than ten percent of the insects weight. One froghopper that is only about two-tenths of an inch long can jump more than two feet!

Forrest M. Mims III and his science are featured online at www.forrestmims.org.

This feature was originally published in Forrest Mims's weekly science column in the Seguin Gazette-Enterprise, Seguin, Texas. The column is written for a general audience.