Geometric Morphometrics Evaluation Of Three-Dimensional Morphology Of Scarab Hindwing Articulations And The Co-Evolution Study

Insects are the only flying invertebrates in known creatures. They are the oldest taxa on earth that can flying. The appearance of wing promotes the high diversity of insects. Its morphology is often used as an important information for identification, classification and high level phylogeny. In this study, the morphology of scarab hind wings, wing base and other related structures was described, illustrated and analyzed by conducting classic and innovative morphological methods and techniques such as optical microscope, micro computed tomography, computer-based three dimensional reconstruction, geometric morphometrics and co-evolutionary analysis.This study examined 55 species which belonged to 18 subfamilies, 11 families of Scarabaeoidea. Three axillary sclerites were reconstructed based on computer-based three dimensional reconstruction approach. There are two types of scarabs concerned with the elytra keeping open or closed during the flight. The morphological variations of wing base and hindwing venations were analyzed based on two-dimensional and three-dimensional geometric morphometrics methods. The correlations between morphological variation of wing base and hindwing venations were analyzed as well. The hind wing results(76.779%) based on 2D GM approach demonstrated that the difference between the hindwing morphology of these two types was significant. In another words, the elytra closed or not during the flight would cause a significant difference in hindwing morphology. There was an important influence from phylogeny on hindwing morphology also. The results of wing base sclerites(1Ax 57.505%; 2Ax 63.361%; 3Ax 45.010%) based on 3D GM approach demonstrated that the difference between the three axillary sclerites' morphology of these two types was significant. In another words, the elytra closed or not during the flight would cause a significant difference in axillary sclerites' morphology. The result of CVA shows that the phylogeny also has an important influence on the morphology of axillary, but the influence on this is smaller than that on venation. According to the results of co-evolutionary analysis between hindwing and wing base sclerites, there is strong correlations(>0.5) between 3Ax and hind wing venation respectively. And there are not strong correlations(<0.5) between the other two sclerites and hind wing.