EXPERIMENTAL HYBRIDIZATION BETWEEN OESOPHAGOSTOMUM-DENTATUM AND O-QUADRISPINULATUM IN PIGS

To investigate eventual hybridization between two nodular worm species of gigs, Oesophagostomum dentatum and O. quadrispinulatum, we used ei ther mature, adult worms or 10-day-old fourth-stage larvae (L-4) as st arting material, employing a nonsurgical transplantation technique. Fo llowing the transfer of adult worms the ensuing first generation of la rvae gave rise to adult worms that were found by morphological examina tion to be purely O. dentatum. Therefore, we decided to use the immatu re L-4 as Starting material. After the transfer of L-4 to recipient pi gs, fecal cultures were established and the L-3 derived from the O. de ntatum male/O. quadrispinulatum female cross gave rise to adult but in fertile worms, which morphologically had the sexual characters of thei r parent generation, whereas other characteristics were intermediate b etween the two species. Attempts to reproduce the hybrid worms or the reciprocal cross were unsuccessful, indicating that hybridization betw een the two species is a rarely occurring phenomenon.