When do yearling male Black-bellied Sandgrouse Pterocles orientalis reach sexual maturation?

Abstract

In the present study, a histological and morphometric investigation of testes in yearling male Black-bellied Sandgrouse Pterocles orientalis was performed during the reproductive period. The trial was conducted on four randomly selected yearling male birds that originated from eggs collected in the wild and artificially incubated. Upon sacrifice, testes were removed and routinely processed for light microscopic examination. Only two birds developed heavy testes, with enlarged tubular diameter of seminiferous tubules. A high correlation was observed between the mean paired testes weight and the total length, diameter of seminiferous tubules and relative seminiferous volume. Two birds presented tubules with a multilayered epithelium and germ cells developed until the stage of round spermatids and spermatozoa. The remaining two birds presented quiescent testes. In conclusion, the yearling males had apparently a relatively shorter breeding cycle and delayed sexual maturation than yearling females, which could explain the low fecundity rate observed in yearling birds of this species in captivity.