Mating activity of Nematospiroides dubius in laboratory mice

Incidence of mating pairs in 40 worm infections in 5 week old female CBA mice increased up to day 30 post infection. By this time, and thereafter until the experiment ended on day 70, approximately 60% of the worm population occurred as mating pairs. Mating began during the ontogenetic migration of the worms. There was no difference between the percentage of worms mating in the more highly populated anterior sections of the small intestine as compared to the less densely populated more posterior sections. Significantly more female than male worms were recovered between days 8 and 20 post infection (P < 0.02 to 0.001) and there was a significant decline in overall recoveries during the experimental period (r = -0.77, P < 0.01). Low intensity infections, with 4 to 16 worms per mouse, demonstrated that a larger percentage of worms in the infection were mating at an earlier time post infection than in the 40 worm infections. Ontogenetic migration was reduced in low intensity infections because the initial distribution of worms was more restricted.