A comparison of biological performances among a laboratory-isolate population and two wild populations of Moniliformis moniliformis

Divergence of biological performance of a laboratory-reared population of M oniliformis moniliformis (Acanthocephala) was investigated after 31 yr. or approximately 60 generations, of genetic isolation. An isolate of the labor atory-reared population and isolates of 2 wild populations were used to beg in 3 independent life cycles that were maintained for 1 generation for inte rbreeding and life history trait comparison. Both wild population isolates represented populations with open gene flow. One wild population isolate re presented a present-day sample of descendants of the parent population of t he laboratory isolate. All 3 populations hybridized. and egg production occ urred in all mixed-sex pairs of different populations. The 3 populations di d not differ significantly in prepatent period, mean daily egg production, or establishment within the definitive host Rattus norvegicus us. The 3 pop ulations varied in patent period, but the laboratory-isolated worms differe d from the 2 wild population isolates no more than they did from each other A positive correlation between mean daily egg production and duration of p atent period resulted in different cumulative egg productions. A 31-yr peri od of isolation did not produce greater divergence in a laboratory populati on of M. moniliformis than occurs between wild populations with respect to the biological parameters measured.