Studies on the Feeding Habits of the Brown Planthopper: II. Honeydew Excretion

Abstract

The honeydew excreted by the brown planthopper, Nilaparvata lugens (Stål), was studied quantitatively and qualitatively with special reference to the planthopper feeding. The frequency of excretion in the female adults varied from 7 to 40 droplets per hour, and the average droplet volume was 0.06 to 0.09μl in most cases. The rate of excretion was therefore estimated at 0.5 to 5μl per hour during feeding. The total amount of daily excretion in one female was 13μl on an average. Although the average concentration of sugars, mainly glucose and sucrose, was about 2%, the planthoppers excreted considerable amount of sugar-free excreta as well as sugar-containing ones. This two fold nature of the excreta might suggest that the insects ingested both the phloem and xylem sap of rice plans. About 0.1% amino compounds occurred also in the honeydew. The main amino acids and amides were glutamic acid, glutamine, aspartic acid, asparagine, and arginine. One female adult was estimated to discharge about 12γ amino compounds and 266γ of sugars every day through excretion. © 1970, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.