Inherited microorganisms, sex-specific virulence and reproductive parasitism

Parasites show an amazing repertoire of adaptations, highlighted by complex life cycles that allow both survival in the host and transmission among ho sts. However, there is one heterogeneous group of microorganisms whose adap tations are perhaps even more surprising: parthenogenesis induction, femini zation of genetic males, killing of male hosts and sperm-mediated steriliza tion of uninfected eggs. The common feature of these microorganisms is thei r mode of transmission: inheritance from mother to offspring. Here, we pres ent an introduction to hereditary symbiosis, focusing on microsporidia and bacteria that manipulate host reproduction in arthropods (reproductive para sites). We also discuss the implications of one of these microorganisms, Wo lbachia, for the control of arthropod pests and vectors and for the therapy of filarial diseases, Finally, we discuss whether some parasites of verteb rates might show sex-specific virulence.