Relative warp analysis of head shape variations in Nephotettix virescens (Distant) (Homoptera: Cicadellidae) infesting rice types with different genes for resistance

Ascaño II, Cordulo P.; Torres, Mark Anthony J.; Demayo, Cesar G.

doi:10.21608/eajbsa.2010.15255

Relative warp analysis of head shape variations in Nephotettix virescens (Distant) (Homoptera: Cicadellidae) infesting rice types with different genes for resistance

Document Type : Original Article

Authors

¹ Current Address: Mindanao University of Science and Technology Cagayan de Oro City, Philippines

² Department of Biological Sciences, College of Science and Mathematics MSU-Iligan Institute of Technology, Iligan City 9200, Philippines

10.21608/eajbsa.2010.15255

Abstract

Head shape differences were examined in both sexes of the green leafhopper Nephotettix virescens (Distant) infesting a susceptible variety TN1, and rice varieties with specific genes for resistance TAPL (Glh6), Ptb8 (Glh4), MK (Glh7), and IR8 (Glh3). Differences in the shapes of the heads were qualified using advances in image analysis and geometric morphometric analysis. A total of 18 homologous landmarks and 2 pseudo-landmarks were digitized from images of dissected head parts of the samples using the ScionImage software. Then, the x and y coordinates of the landmarks were examined using relative warp analysis and principal component analysis. Results of the Kruskal-Wallis test (non-parametric ANOVA) of the head shape descriptors showed clear-cut divergence in the shapes of the heads of some green leafhoppers infesting resistant rice types (P<0.001). In the context of evolution, such observation shows that ecological divergence following host shifts may also be an important factor in the diversification of lineages of herbivorous insects. Such host races can thus serve as models to test hypotheses about the factors driving local specialization that can lead to reproductive isolation and speciation.

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