Feeding Activity of Adults of the Oriental Armyworm, Pseudaletia separata Walker

Abstract

Feeding behavior of the adult armyworm was observed in two field cages (2×2×2) with and without the supply of a brown sugar solution as food, and in a cage kept at of the constant room temperature of 21.5 ± 1.5°C with the supply of a sugar solution as food. Only a very small number of adults was attracted to the food on the 1st day after emergence. Active feeding started on the 2nd day and reached a peak on the 3rd or the 4th day. The daily feeding peaks which occurred just after sunset (or light-off) and again before sunrise (or light-on) from the 2nd day to the 5th day, were less distinct on the 7th day on account of a rather continuous activity. The adults, which did not receive the sugar solution, took the honeydew from aphids on corn plants, mated and oviposited normally, though they showed a slightly lower percentage of mating than those fed on the sugar solution. Daily intake of sucrose solution per adult female and its effect on oviposition were investigated in 900 ml glass cups, with the supply of 0.1, 1, 3, 5, 10 and 30% sucross solutions. The peak feeding occurred earlier, and the total amount of sucrose absorbed per female increased linearly, with increasing concentration of the sucrose solution. The number of eggs laid per female increased with the sucrose intake within the 0.1–10% range, and decreased at a concentration of 30%. Starvation of adult females decreased fecundity, but not egg hatchability. © 1987, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.