Natural enemies of the rice greenhorned caterpillar Melanitis leda Ismene (Lepidoptera: satyridae) and rice skipper Pelopidos mathias (Lepidoptera: Hesperiidae) in the Philippines
1997
Litsinger, J.A. | Barrion, A.T. | Bumroongsri, V. | Morrill, W.L. | Santhoy, O. (International Rice Research Inst., P.O. Box 933, 1099 Manila (Philippines). Entomology and Plant Pathology Div.)
The natural enemy complex of the two most common rice butterflies in the Philippines, namely, the rice greenhorned caterpillar Melanitis leda ismene Cramer (Lepidoptera: Satyridae) and rice skipper Pelopidas mathias (Fabricius) (Lepidoptera: Hesperiidae), was described. More predators (83 species) were recorded than parasitoids (30 species) or pathogens (4 species). Of the predators, 59 percent preyed on both butterflies, whereas only 37 percent of the parasitoids shared hosts. Among the predators 52 percent attacked larvae, 28 percent the eggs, 19 percent adults, and 1 percent pupae. One third of the parasitoid records were each larval and larval-pupal, 21 percent egg, and 13 percent pupal. From 1977-91, periodic collectitons in 12 locations representing three rice environments recorded parasitization rates averaging 12.2 percent vs 14.5 percent for egg and 11.0 percent vs 12.6 percent for larval-pupal stages of M. leda ismene and P. mathias, respectively. Monthly P. mathias egg and larval-pupal parasitization levels for 1988-89 were consistent between life stages but ranged from 10-80 percent. The impact of parasitoids was concluded to be insufficient alone to cause the observed low population densities of both butterflies. While the role of pathogens was judged minimal, greenhouse studies indicated predators had high potential and have been overlooked as regulatory agents of rice butterflies
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