HORIZONTAL TRANSFER OF PARASITIC SEX-RATIO DISTORTERS BETWEEN CRUSTACEAN HOSTS

Parasitic sex ratio distorters were artificially transferred within an d between crustacean host species in order to study the effects of par asitism on host fitness and sex determination and to investigate paras ite-host specificity. Implantation of Nosema sp, to uninfected strains of its Gammarus duebeni host resulted in an active parasite infection in the gonad of recipient females and subsequent transovarial parasit e transmission. The young of artificially infected females were femini zed by the parasite, demonstrating that Nosema sp. is a cause of sex r atio distortion in its host. In contrast, eve were unable to cross-inf ect Annadillidium vulgare with the feminizing microsporidian from G. d uebeni or to cross-infect G. duebeni with the feminizing bacterium Wol bachia sp. from A. vulgare.