Relative Warp Analysis of the Pronotum Shape Variability among Twelve Selected Populations of the Coconut Leaf Beetle, Brontispa longissima Found in the Mindanao Island

Abstract

Abstract-The aim of the study was to determine the pronotum shape variability of the coconut leaf beetle, Brontispa longissima and to identify the shape discontinuity using relative warp analysis. Samples were taken from twelve sampling site under eight provinces in Mindanao. Using the results from the relative warp analysis, histograms, CVA and box plot were generated to visualize variation distribution. Cluster analysis was used to determine the degree of variation between pronotum shape and within populations, with the Kruskal-Wallis test used to determine the significance of difference. Results of the relative warp (RW) analysis showed six general and significant descriptions of pronotum shape. CVA scatter plots showed intrapopulation variation in pronotum shape but Kruskal-Wallis test showed significant differences in several populations. Cluster analysis resulted in the formation of two subclusters in each grouping. The observed morphological disparity among the selected Brontispa populations suggested possible morphological divergence between and within populations. It was concluded that there is a significant relationship in the pronotum shape of B. longissima with regard to its shape variation.Index Terms-Coconut leaf beetle, geometric morphometrics, landmarks, pronotum, relative warp analysis.