Consideraciones acerca de la evolución de las piezas bucales en los Onthophagini (Col.: Scarabaeidae)en relación con diferentes regimenes alimenticios.

In order to contrast the hypothesis that different sectors of the trophic spectrum of the Onthophagini could correspond to structural modifications concerning the general scheme of their mouthparts, several Onthophagini which are strictly associated with rodents’ burrows or bats’ guano were studied. The following species were selected: Onthophagus (s.str.) hippopotamus Bates, exclusive of rodents’ burrows, O. (s.str.) vespertilio Howden, Cartwright and Halffter, exclusive of caves, and two other, free-living species: Onthophagus (s.str.) incensus Say and O. (s.str.) c. chevrolati Har. Digitonthophagus gazella (Fab.) and Onthophagus (Relictonthophagus) punctatus (Ill.) were used for external comparison. The results show that no substantial difference exist between the Onthophagus species of burrows or caves and those living in a open environment, which strengthens the idea that the principal factor affecting the evolution of these structures is food consistency. Moreover, the results also suggest a relation between mouthparts development, and huge evolutionary success of D. gazella.