Figure 1. O. taurus life cycle.

Adults fly into the dung pat to feed and mate. Beneath the dung pat, the juvenile life stages of Onthophagus taurus are isolated in the brood chamber of the brood balls constructed by the female beetles in tunnels. Females lay several brood balls in each tunnel that would all be at the same developmental stage. However, for illustrative purposes all life stages are represented in one tunnel. These stages include the: (A) egg, (B) 1^st larval instar, (C) 2^nd larval instar, (D) 3^rd larval instar, (E) pupa, and (F) an eclosing adult beetle that is tunneling toward the surface. The brood ball chamber is larger with each successive life stage as the larva feeds on the chamber walls within the brood ball. The top inset shows (G) the fecal pedestal the egg is positioned upon in brood ball. The bottom inset shows (H) the larval instar feeding on the walls of the brood ball chamber.