Microstructure and diversity of the bursa copulatrix wall in Tortricidae (Lepidoptera)

The inner surface and muscle structure of the bursa copulatrix are examined for the first time with Electron Microscopy in some representatives of the family Tortricidae (Lepidoptera). The internal microprotuberances reveal taxon dependent characters unstudied in the Lepidoptera until now. Acanthae occur in almost all taxa studied, whereas ctenidia and papillae are found only in representatives of Tortricinae and Olethreutinae, respectively. Muscles are radially arranged from the signa. Areas of muscle insertion on the bursal wall are not covered by other muscle fibers. Muscle attachments to evaginated areas, e.g. capitulum and diverticulum, suggest an apodeme role for these structures, correlated with long protruding signa. The potential evolutionary and adaptive significance of these new findings are discussed.

► First comparative report of the microstructure of the bursa copulatrix wall.
► The microstructure of bursa copulatrix wall is taxon dependent.
►  Diversity of microprotuberances includes acanthae, ctenidia and papillae.
► The signum teeth may represent transitions from microtrichiae of the integument.
► Muscles attach to signum and non signum areas where epithelium is exposed.