Wax Production in Adults of Planthoppers (Homoptera: Fulgoroidea) with Particular Reference to Metcalfa pruinosa (Flatidae)

Although wax characteristics, wax-producing structures, and their probable functions in planthopper juveniles have been summarized in recent articles, very little has been published regarding the morphology of these structures in adults. In the Nearctic ßatid Metcalfa pruinosa (Say), most wax is secreted on the forewings of both sexes and on the anal tube of females. There is also a sparse powdery layer of wax that lightly covers most of the body. Along most of the body surface and forewings many small glandular ring-shaped areas occur, delimiting a pore, from which single thin Þlaments of wax emerge. Moreover, numerous moniliform glandular pore-plates are randomly scattered on the surface of the forewings. On each plate, 8Ð50 subcircular pores are symmetrically arranged in one or two lines around a long central sensory hair. An internally hollow cylindrical wax ribbon emerges from each pore. In addition, many prominent glandular plates occupy the ventral surface of the female anal tube. Each plate is nearly circular and is marginally perforated by seven to eight pores from which long, hollow, cylindrical wax tubules emerge. These plates are not present on the anal tube of the male. Although the function of the anal tube wax is unknown, the wax layer that covers the body and forewings may play an important role in protection against abiotic factors and prevent smearing the cuticle with honeydew.