|Publication Type:||Journal Article|
|Year of Publication:||2003|
|Authors:||M., IMartinez, Lumaret, J-P|
|Journal:||m3m: Monografias Tercer Milenio|
|Keywords:||larvae, Scarabaeoidea, sexual dimorphism.|
A well defined sexual dimorphism is present in scarabaeoid larvae. Dimorphism was observed in late-age larvae of some species of Scarabaeidae, Aphodiidae, Trogidae, Orphinidae, Dynastidae, Passalidae and Lucanidae. This dimorphism manifests itself in the presence of a terminal ampulla, a cuticular structure situated in the ventral region of the 9th abdominal segment which is only present in male specimens. In Scarabaeidae, sexual dimorphism was only observed in the pupae of six species. The terminal ampulla in Canthon cyanellus cyanellus LeConte (Scarabaeidae) is present in the male larvae apparently since the first instar, and changes morphologically during the next larva instars. Only a detailed study of the morphogenesis of the terminal ampulla during the larval and pupal stages could help to define exactly what structures of the ejaculatory bulb and aedeagus it will turn into in the adult stage.