This week we continue our adventures beyond the dreary confines of Maryland and visit the cloud forest of Costa Rica to meet some beautiful froghoppers.
Here: Froghopper is the common name given to a large family of insects technically known as Cercopidae. These sucking insects belong to a large clan called Hemiptera that includes stink bugs, assassin bugs, scale insects, and aphids we met in previous episodes. Many adult froghoppers here in Maryland sport rather drab colors of gray or brown or cryptic shades of green, and are not often seen during casual excursions to the garden. However, immature stages of froghoppers are called spittlebugs and their frothy masses are a sight well known by most gardeners. While many have observed the spittle produced by spittlebug nymphs, a safe wager it is that few have cleared away the bubbles to see the rather adorable green nymphs enshrined within.
Spittle is a fairly innocuous mix of excess plant fluid voided by the nymph, proteinaceous glandular secretions, and air bubbles introduced by clever contortions of the nymph. The spittle serves to keep the developing nymph moist and insulated from extreme temperatures, and also to serve as a deterrent from attack by stinging parasitoids and hungry predators. Would self-respecting birds really wade through a glob of spittle in search of a buggy meal? After molting several times within their bubble home, nymphs turn into winged adults. Adults suck plant sap to obtain nutrients and excrete excess sap in the form of honeydew, as do other sap-suckers including aphids and soft scale insects. Here in Maryland, most spittlebugs and froghoppers are found in meadows on grasses and herbaceous plants, causing no economic damage. However, one species, Philaenus spumarius, has been reported as a pest of clover.
There: In the cloud forests of Costa Rica, spittle looks pretty much like spittle found on our herbaceous plants back in Maryland. By contrast, equatorial froghoppers often come decked out in harlequin colors not often seen in their temperate cousins. Striking contrasting colors of tropical froghoppers are believed to warn predators of their distastefulness much the same way as aposematic coloration of monarch butterflies, milkweed bugs, and other denizens of Asclepias warn potential predators like birds and non-feathered reptiles of a potentially noxious meal. As do their relatives to the north, tropical froghoppers process large volumes of plant sap. While watching these jungle beauties feed, I was amazed by the steady stream of honeydew droplets squirted by the spittle bugs as they fed.
When spring returns and spittle begins to appear on plants in the garden, take a moment to brush back the bubbles and enjoy these curious sap-suckers.
Watch the steady stream of honeydew droplets excreted by this beautiful froghopper as it sucks plant sap.
The great reference “An Introduction to the Study of Insects” by Donald Borer, Dwight De Long, and Chuck Tripplehorn was used as a reference for this episode.