Relative Warp Analysis of Shape Variability of the Head and Pronotum In Selected Populations of the Rice Black Bug

The landmark-based geometric morphometric approach of relative warps (RW) was used to determine the population structures of the rice black bugs (RBB), Scotinophara coarctata, from the Philippines and in one site in Malaysia based on the shapes of the head and pronotum. The symmetric and asymmetric components were used to analyze the direction of shape change for each structure. However, multivariate analyses were conducted only on the symmetric components to infer the relationships among the RBB populations. The results showed that in many cases, the landmark configurations are continuous. Landmark configurations of the pronotum separated the RBB from Omar, Malaysia. Considerable shape differences between populations were also found locally within Luzon, Iloilo, Palawan and Mindanao based from the results of the analyses. The results of the current study strongly suggest the existence of morphological differences in the populations of RBB, which may indicate possible genetic differentiation. Such variability may have direct bearing on the management of the RBB as a pest of rice agroecosystem