Horizontal transfer of parasitic sex ratio distorters between crustacean hosts

A. M. DUNN a1c1 and T. RIGAUD a2
a1 Department of Biology, University of Leeds, Leeds LS2 9JT, UK
a2 Université de Poitiers, Laboratoire de Génétique et Biologie des Populations de Crustacés, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex, France


Parasitic sex ratio distorters were artificially transferred within and between crustacean host species in order to study the effects of parasitism on host fitness and sex determination and to investigate parasite–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 parasite transmission. The young of artificially infected females were feminized by the parasite, demonstrating that Nosema sp. is a cause of sex ratio distortion in its host. In contrast, we were unable to cross-infect Armadillidium vulgare with the feminizing microsporidian from G. duebeni or to cross-infect G. duebeni with the feminizing bacterium Wolbachia sp. from A. vulgare.

(Received December 1 1997)
(Revised February 11 1998)
(Accepted February 11 1998)

Key Words: artificial infection; Nosema sp.; Wolbachia sp.; sex ratio distorter; feminization.

c1 Corresponding author: Department of Biology, University of Leeds, Leeds LS2 9JT. Tel: +0113 2332856. Fax: +0113 2332835. E-mail: