Feeding Behavior of <i>Nephotettix virescens</i> (Homoptera: Cicadellidae) on Suitable and Unsuitable Host Plants and Underlying Mechanisms of Host Plant Suitability

Abstract

<i>Survivorship, developmental rate, fecundity, intrinsic rate of increase, and feeding behavior of the rice green leafhopper</i>, Nephotettix virescens <i>Distant, were studied on 6 rice cultivars and 2 graminaceous weed species</i>, Leersia hexandra <i>Swartz and</i> Zizania latifolia <i>Turcz.</i> N. virescens <i>survived on all 6 rice cultivars, but differences existed among cultivars.</i> N. virescens <i>did not survive on the 2 weed species.</i> N. virescens <i>ingested phloem sap from the 6 rice cultivars but did not ingest phloem sap from the 2 weed species, suggesting that failure of</i> N. virescens <i>to survive on the weeds may be caused by an inability to ingest from the phloem of these plants.</i> L. hexandra <i>and the rice cultivar Nihonbare then were selected as an unsuitable and suitable host, respectively, for further comparisons. Water soluble extracts from Nihonbare and</i> L. hexandra <i>were fractionated into acidic, basic, neutral, and amphoteric fractions.</i> N. virescens <i>then were fed artificial diets of 2% sucrose, or 2% sucrose plus 1 of the extract fractions, or 2% sucrose plus the unfractionated water extract of each plant. Extracts–fractions from Nihonbare had little, if any, effect on</i> N. virescens <i>survival, whereas the water-soluble extract of</i> L. hexandra <i>and its basic, acidic, and neutral fractions (but not the amphoteric fraction) caused virtually complete mortality of</i> N. virescens <i>within 6 d. Additional experiments indicated that the basic, but not the amphoteric, fraction of</i> L. hexandra <i>inhibited ingestion of artificial diet.</i>