Planthopper/Plant Interactions: Feeding Behavior, Plant Nutrition, Plant Defense, and Host Plant Specialization

Abstract

Host plant allelochemistry and nutrition have figured prominently in understanding the feeding behavior, host plant range, population dynamics, and life history strategies of phytophagous insects (McNeill and Southwood 1978; Rosenthal and Janzen 1979; Denno and McClure 1983). For sap-feeding insects such as delphacids, host plant nutrition is thought to influence host plant selection, performance, and population growth and dynamics (Dixon 1970; Waloff and Solomon 1973; McNeill and Southwood 1978; Denno et al. 1980; Waloff 1980; Prestidge and McNeill 1982; Denno 1983, 1985a; Denno and Roderick 1990). However, far less information is available on the role of secondary plant chemistry in sap-feeder/plant interactions (Denno and Roderick 1990). Two factors have undoubtedly contributed to this historical emphasis on host plant nutrition. First, phloem-feeding planthoppers are thought to avoid many allelochemicals that are compartmentalized in nonvascular tissues (Waloff 1980; Sogawa 1982). Also, complex secondary chemicals such as glucosinolates, terpenoids, alkaloids, flavonoids, and phenolics are either absent or occur in low concentrations in grasses and related monocots, the most often recorded host plants of planthoppers (Culvenor 1970; Butler and Baily 1973; Harborne and Williams 1976; McNeill and Southwood 1978; van Etten and Tookey 1979; Waloff 1980; Prestidge and McNeill 1983).