RESEARCH ARTICLE

Journal of Oil Palm Research Vol. 7 No. 1, June 1995, p. 18-34

LIFE HISTORY AND FEEDING BEHAVIOUR OF THE OIL PALM BAGWORM, METISA PLANA WALKER

MOHD BASRI, W*; KEVAN, P G **

ABSTRACT

Bagworms were reared in a controlled environment room (CER) to obtain details of their life history. Eggs were pale yellow and barrel-shaped, and their incubation period was 19.7 ± 0.3 days. Fecundity of laboratory-reared females was higher than that of wild-caught females (158.3 ± 10.3 vs 99.9 ± 5.7 eggs/ female) yet lower than those recorded for several other species of Psychidae. Fertility was high (generally > 90%). Sexual dimorphism in instar number was recorded (5-6 for males vs 6-7 for females). Head capsule widths, bag lengths and morphology can be used to determine instars. Most leaf tissue removed from oil palm foliage (66.8%) was used for maintenance and body growth, and the remainder for bag construction. Larvae preferred upper leaf surface for feeding and lower surface for resting and moulting. Sexual dimorphism was also noted in pupal size (males smaller than females) and developmental time (males, 21.4 ± 0.3 days; females, 10.0 ± 0.4 days). Total developmental times of males and females did not differ, suggesting that overlapping generations are not a requisite for an outbreak. Sex ratio was male biased (8.5:1).

KEYWORDS:


* Palm Oil Research Institute of Malaysia,
P.O. Box 10620, 50720 Kuala Lumpur, Malaysia.

** Department of Environmental Biology,
University of Guelph, Canada.