Geometric Morphometric Analysis of Individual Variation in Bumblebee Wings

Abstract

The morphological features of an organism are an important source ofinformation for many areas of biological study. Insect wing architectural designis believed to be an excellent system for studying morphological variation becauseof their firm or solidly cleared structures. It has been the center of geometricmorphometric investigation in the past since insect’s wing pattern can providedetails on their evolutionary history and flight performance. Wing shape andsize disparity of fifty-nine individuals of bumblebee was explored to explain andfigure out biological structure variation within similar species. Examination inboth left and right forewings and hind wings was also considered to find out ifphenotypic sexual dimorphism exists. The outline-based geometric morphometrictechnique was employed in this study to measure and evaluate wing shape andsize variation among bumblebees. Results from mean shapes and scatter plotdiagrams analysis revealed that individuals of bumblebee differ less with respect to shape. Overlapping of individuals is visible on both wings in both sexes, which shows absence of dimorphism. Male individuals have larger forewings comparedto females. Slight variation was observed for both sexes in terms of hind wings,which indicates that both individuals exhibit common size characteristic andabsence of dimorphism. The study concludes that size may be considered as abasis for sex determination and that wing size is somewhat a sexual dimorphictrait among bumblebee species. Keywords - Biology, wing morphometry, outline-based geometric morphometric analysis,Philippines