From spitters to high jumpers
Emily Post would not approve. Someone's been spitting in the fields for the past two months. Who's responsible for this uncouth behavior? Spittlebugs, that's who.
A spittlebug begins as a tiny egg in a plant stem. The "bug" emerges and begins feeding on plant juices. This is a nymph, the young form of an insect whose job is to eat, eat, eat, and grow, grow, grow. The nymph will take on a different name as an adult, but when young and spitting it is aptly called a spittlebug.
The nymphs appear in late April and immediately start to produce frothy bubbles. The common belief is the froth protects the little spittlebugs from would-be predators like birds. (Would you want to poke your bill into a wad of spit?) More importantly, the spittle insulates the nymph from temperature extremes and keeps the nymph moist during hot, dry days.
Check out the spit. (Really, go ahead!) It feels like foamy water. If you gently part the bubbles you'll find the nymph inside, a yellowish-green little guy, about ˆ¼ inch long, well camouflaged on its host plant.
Technically the foamy stuff is not really spit, as it comes not from the mouth but the other end. The nymphs feed with their face buried in the plant - better to suck juices - and hold their rear ends up - the better to produce foamy bubbles. Two structures on the underside of the abdomen serve as bellows pumping air as a viscous fluid made of glycoproteins is excreted. According to Susan Mahr of the University of Wisconsin-Madison, "The spittlebug moves its abdomen up and down and as the bubbles emerge, it reaches back with its legs and pulls the bubbles forward over its back." The resulting spittle creates a perfect air-conditioned and protective environment for the small nymph.
After about two months, the spittlebugs are ready to emerge from their frothy fortress and enter the world as adults. If you're patient, you can watch this coming of age right now. Go find some spittle on a plant in the field and watch. Chances are that a young adult is emerging or has just emerged and is hanging out on a leaf, checking out the big, wide world ahead.
At this time, the spittlebug is no longer called a spittlebug, but rather a froghopper. Watch closely. They do have a froggy kind of look. And like frogs, they jump. Boy, do they jump! Froghoppers hold the record of long jumps and high jumps put together. It was formerly believed that the flea was the best jumper in the animal kingdom, but recent research has shown the froghopper to be the champ. With leaps greater than two feet, the froghopper's feat is equivalent to "a man jumping over the Gateway Arch in St. Louis," according to a National Public Radio report. Cambridge University entomologist Malcolm Burrows has studied froghoppers' leaps with high-tech cameras that capture 2,000 images per second. "His photographs," reports NPR's Jon Hamilton, "show that a froghopper - accelerates 10 times faster than [a flea]. That speed on such a small body subjects the bug to 400 times the force of gravity- Pilots diving through the sky in a fighter plane reach about 10 Gs, but they need a pressure suit to survive."
Thus, this is an amazing little insect. In addition to its place in the Insect Jumpers' Hall of Fame, it brings with it a fair share of folklore. Spittlebugs are found in Europe as well as North America, and according to Adrian Morgan's Toads and Toadstools, froghoppers played a role in ancient rituals. "In East Anglia," writes Morgan, "witches were said to take toad's spittle [from the froghopper] and mix it with the sap of sow thistle to make a lather. The lotion would be applied to the body - in order to make the witch invisible." In many places, the spittle of the spittlebug is called cuckoo spit. This tag is applied because spittlebugs appear when the first cuckoos of spring are heard.
Where are these critters in the grand scheme of things? Talk to a farmer and a gardener and they will tell you that these insects are pests. Both the spittlebug nymph and the adult froghopper damage alfalfa crops and horticultural plantings of arborvitae, roses, and Shasta daisies, among other plants. The University of Illinois's Integrated Pest Management Web site reports that spittlebugs "may cause losses in (alfalfa hay) yield varying from slight to 25 percent or more. An average of one nymph per stem can decrease the yield of dry hay by 300 or more pounds per acre."
The severity of damage on most native plants, however, is minimal. In our natural areas, spittlebugs are more a curiosity for hikers than a pernicious enemy to be eradicated. The spittlebug's favorite haunts in prairies and fields are goldenrods, grasses, and daisies and their kin. Although these plants may be temporarily stunted by spittlebugs, the vegetation overall remains healthy.
On your next walk along a forest preserve trail, look for the last of this season's spittle and the new generation of high-jumping froghoppers. Forget Emily Post. Marvel at the adaptations of these insects, the spitting and leaping champions of the world.
Valerie Blaine is the nature program manager for the Forest Preserve District of Kane County. blainevalerie@kaneforest.com