Objective  Effect of forage on fecundity of the highly reproductive and widely spread polyphagous pest, Spodoptera litura Fabricius, was studied.

  Method  Under the laboratory conditions, insects were raised individually on different diet or host plant to monitor the effects on the fecundity, vitellogenin (Vg) and vitellogenin receptor (VgR) of adult S. litura.

  Result  No significant differences were observed on the lifespan and response of the pre-oviposition insects as they were fed on a formulated diet, Brassica oleracea, Alternanthera philoxeroides or Ipomoea batatas. On the other hand, the fecundity, Vg and VgR of the adult females differed significantly whether they were on the formulated diet (control) or the host materials. An individual adult female on the formulated diet would produce 889±43.0 eggs; whereas, one on I. batatas laid 496±53.1 eggs; one on A. philoxeroides, 362±37.3 eggs; and, one on B. oleracea, 193±9.7 eggs. The relative Vg and VgR transcript levels of the female moth population fed on the host materials were merely 40% to 80% of those of control. And, those measurements correlated well with the fecundity of the insect.

  Conclusion  After feeding on various hosts, the titers of Vg and VgR of S. litura differed in comparison to control diet which directly affected the egg development and fertility of the insect.