PARTHENOGENESIS IN THE GENUS SCHISTOSOMA - ELECTROPHORETIC EVIDENCE FOR THIS REPRODUCTION SYSTEM IN SCHISTOSOMA-JAPONICUM AND SCHISTOSOMA-MANSONI

Mixed infections with Schistosoma japonicum and S. mansoni were carrie d out in mice. S. japonicum females paired with S. mansoni males devel oped normally and produced numerous viable eggs; very little sperm was found in the female genital tract. The eggs yielded many miracidia in fective to Oncomelania hupensis, the host of S. japonicum. Cercariae a rising from miracidia developed into male worms with an electrophoreti c pattern of malate dehydrogenase (MDH) corresponding only to the mate rnal species S. japonicum. S. mansoni females paired with S. japonicum produced few viable eggs; sperm was found in the female genital tract . Miracidia hatched from some of these eggs were infective to Biomphal aria glabrata, the host of S. mansoni. Cercariae arising from miracidi a developed into female worms with an electrophoretic pattern of MDH t ypical of the maternal species S. mansoni. It was concluded that S. ja ponicum females paired with S. mansoni males and S. mansoni females pa ired with S. japonicum males reproduce parthenogenetically. Parthenoge nesis in schistosomes is discussed.