The Dynamics of Hybrid Sterility Between Boophilus Annulatus and B. Microplus (Acari: Ixodidae) Through Successive Generations1

Abstract

Interspecific crosses between Boophilus annulatus and B. microplus produce viable progeny (F₁,) in which all males are sterile, but females are fertile when backcrossed to the original male parent species. The progeny obtained by backcrossing the F₁ female (BCI) also contain all sterile males, but fertile females. This pattern of sterile males and fertile females continues through 3 generations of crosses (F₁, BCI, and BCII). Some fertility is observed in hybrid males in the 4th generation of backcrosses, and by the 7th generation hybrid male fertility equals that of controls.