Details of reproduction in Tylenchulus semipenetrans and Cacopaurus pestis (Nematoda:Criconematoidea).
Gametogenesis in Tylenchulus semipenetrans is by meiosis; possibilities from amphimixis and parthenogenesis occur but the 2nd is probably rare in natural conditions. Populations from France, Morocco, Algeria and Iraq all had n = 5. At some stages, chromosomes are large and diverse in morphology. 2nd-stage female larvae are sexually undifferentiated, capable of developing to giant males if they stop feeding, or to normal females. In Cacopaurus pestis, oogenesis is by meiosis, reproduction is amphimictic and n = 5 or 6. The variation in number is thought to be polysomic, not sex-linked. Cytogenetics of the Criconematoidea is discussed.