Variability in head shapes in three populations of the Rice Bug Leptocorisa oratorius (Fabricius) (Hemiptera: Alydidae)

Document Type : Original Article

Authors

Department of Biological Sciences, College of Science and Mathematics, Mindanao State University-Iligan Institute of Technology, 9200 Iligan city, Philippines

Abstract

The rice bug, Leptocorisa oratorius (Fabricius) is an insect pest of rice that feeds on developing rice grains reducing the yield and quality of rice. Identification of this pest has been vague owing to variability in its external morphological characteristics. It has been referred to as L. acuta (Thunberg) and  L. varicornis in some literature. In this study, the shapes of the head capsule were compared in populations of the rice bug using a landmark-based geometric morphometric method, and analysis of relative warp scores. Samples were collected from three different localities of which eighty-three were from Alubijid, Misamis Oriental; nineteen from Maigo, Lanao del Norte; and eighty-two from Buug, Zamboanga Sibugay. Of the 184 individuals, 116 were classified as males and 68 were classified as females. Images of the dissected head capsule was acquired with the use of MacronCam and Leica ES2 microscope. Landmark analyses was done on the x- and y- coordinates of the head outline which totalled to 35 landmark points. The results showed variability within and among populations of the rice bugs in the regions at the labrum, vertex, and the outline of the compound eye insertion.This variability may represent unique genotypes and that this geographic variation may have an important effect on expanding population sizes in following years which should be considered in control methods.

Keywords

Egyptian Academic Journal of Biological Sciences. A, Entomology
Volume 3, Issue 1
June 2010
Pages 173-184

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