Family: Cercopidae
Subfamily: Cercopinae
Length: males 8.0-10.8 mm; females 7.7 to 9.8 mm
Prosapia bicincta ranges from Central America to Colorado to Maine and to Florida. In West Virginia it is widespread and common.
As in other members of this family, the newly emerged nymphs produced a mass of bubbles ("spittle") on the plant stem, often within five minutes of first feeding. Researchers have advanced several theories about the function of the spittlemass. It may be primarily a way of hiding the nymphs from predators, it may function to prevent desiccation, it may offer protection from fungal pathogens, or may play a role in osmoregulation (regulation of the pressure and chemical content of bodily fluids).
Peck (2002) investigated reflex bleeding in the Two-lined Spittlebug. When predators attack, the bugs release hemolymph from pads on the pretarsi. The pads rupture along predetermined lines in order to release the hemolymph. The bugs are able to replenish the exudate within six hours, given access to food.
While Peck wasn't able to isolate the precise role of the released hemolymph in protecting the spittlebug (it did not seem to be chemically deterrent), he believed that a combination of warning colors, warning odors, and the sudden release of hemolymph "form an elaborate warning signal." Presumably the exuding of hemolymph is a startle stimulus that allows the spittlebug to jump to safety. Unlike many other kinds of insects, spittlebugs and other Homoptera need only to make the predator pause for a instant before they are able to launch themselves into a leap the predator won't be able to follow.
Peck captured 53 other spittlebug species and "tasted the venter and legs for the distinctive tasting fluid." The fluid was orange and not repulsive (to humans, anyway). Of the 53 species, 42 demonstrated reflex bleeding and 11 did not; the eleven appear to rely primarily on camouflage to avoid predation, while the reflex bleeders were usually brightly colored.
Nachappa, Guillebeau, Braman, and All (2006) conducted laboratory studies of predation upon Prosapia bicincta, and they too found the reflex bleeding was not a chemical deterrent. Pairing common generalist predators with the spittlebugs, the researchers found Wolf Spiders in the genus Lycosa were not among the more voracious predators of the Two-lined Spittlebug. Species that were voracious predators included the Big-eyed Bug Geocoris uliginosus and G. punctipes; a Fire Ant Solenopsis invicta, and a Tiger Beetle Megacephala carolina. Other significant predators included two Ground Beetle species, Harpalus pensylvanicus and Calosoma sayi.
Nymphs of the Two-lined Spittlebug feed on the roots of grasses, while adults are broad feeders on deciduous trees, shrubs, herbaceous plants, and grasses.
Above: This Prosapia bicincta has fallen prey to a Robber Fly (Asilidae). Prosapia bicincta has one generation per year, overwintering in the egg stage. Low temperatures seem required for development of the eggs to proceed. West and Lees (1988) found the best hatching success in eggs that had spent 83 days at 2° to 5° C.
Insects of West Virginia
