Ground Plan and Evolution of Pterothoracic Musculature of Moths and Butterflies (Lepidoptera)

摘要

Investigation of the meso- and metathoracic musculature in 62 species of Lepidoptera revealed 40 topographically different muscles, 37 of which presumably belong to the ground plan. The archaic (homoneuran) taxa demonstrate a higher similarity in themusculature of the meso- and metathorax than more advanced (heteroneuran) taxa do. The number of muscles increases with body size but does not depend on the forewing shape or the surface area ratio of the hind and fore wings. Reduction of many muscles occurred repeatedly thus causing similarity between phylogenetically distinct lineages; development of new muscles is rare and occurs mostly as a result of splitting of a muscle into morphologically different parts. Decrease in the number of muscles is accompanied by an increase in their size, more advanced groups generally having relatively larger muscles, especially in the mesothorax. The thoracic anatomy of Lepidoptera is strongly linked with biomechanics of flight and therefore has a relatively low value for phylogenetic analysis, although some characters may be used in reconstruction of phylogeny at the level of subfamilies to superfamilies.