| Popis: |
About 2,000 specimens of the quadrigyrid acanthocephalan Acanthogyrus (Acanthosentis) tilapiae (Baylis, 1948) were collected from 9 species of cichlid fish hosts (Cichlidae: Perciformes) in 7 different sites in Lake Malawi, Africa, during September 2005. New host records are noted in 5 species, Labeotropheus trewavasae (Fryer), Melanochromis vermivorus (Trewavas), Nimbochromis polystigma (Regan), Tropheops microstoma (Trewavas), and Rhamphochromis sp. (Regan). High prevalence of A. tilapiae was observed in all host species analyzed. The parasite manages to infect its cichlid hosts, despite their distinct trophic specializations. Nevertheless, significant variation in parasite load was detected between sympatrically occurring rock-dwelling (mbuna) cichlids, with Pseudotropheus zebra (Boulenger) showing the most heavy infections. In addition, significant variation in parasite burden was detected between sampling locations, but host gender and weight did not explain significant variation in the numbers of A. tilapiae individuals. Differential exposure to parasites and host susceptibility may explain the marked variation in parasite abundance among cichlid hosts. Worms appear to be recruited in the summer, develop and mature through the winter, and reproduce sexually in late winter and spring. |
