Disparity in the pronotal shapes between sexes in the two populations of Brontispa longissima (Gestro, 1885) from Caraga region, Philippines using landmark-based geometric morphometrics

Abstract

The study was conducted to describe the disparity in the pronotal shapes of Brontispa longissima populations in Caraga region, Philippines. Relative warp analysis was utilized for quantifying the shape while Canonical Variance Analysis (CVA) was used to compare shape variation between populations. Results from MANOVA test showed that individual symmetry has high significant values (p<0.05). In terms of determining the different variations between populations, pooled males have the p value of 7.62*10^(-15) and pooled females have 8.54*10^(-6), wherein the two values display high significant scores between the two sexes. Moreover, determining the disparity of both sexes from the two geographical locations, Surigao population has the highest p value of 7.63*10^(-15) compared to Agusan population which obtained 6.072*10^(-12), manifesting that populations from the two locations vary in the shape of the pronotum. CVA scatterplot also generates population discrimination indicating the presence of sexual dimorphism in pronotal shapes, while biogeographical factor may affect the shape structure in the pronotum of B. longissima