Polystoma australis (Monogenea): Development and reproduction in neotenic parasites

Development and reproduction of neotenic Polystoma australis were investigated in natural anuran Kassina and Semnodactylus hosts in South Africa. Newly established parasites attached mainly inside the left branchial chamber. They then migrated so that parasites older than eight days occurred almost exclusively in the right branchial chamber. Mortality was high and continuous. In young worms age could be readily determined from haptoral structure. At 23°C the developing reproductive system was discernible at seven days. Egg production started at 16 days and could be maintained at constant rates of around 10-20 eggs/ parasite/day for up to 40 days. No crowding effect influencing parasite development or reproduction could be established. These developmental standards could be used to measure the success of parasites subjected to experimental conditions.