The rate of development of Polylabroides multispinosus (Monogenea: Microcotylidae) parasitic on the gills of Acanthopagrus australis (Pisces: Sparidae).

Experiments were done to determine the rate of development of Polylabroides multispinosus. Eggs hatch after an average 9, 7 and 6 days at 20, 24 and 28 degrees C, respectively. The ciliated oncomiracidium hatched with one pair of clamps (c.p.). Juvenile worms less than 3 days post-infection (p.i.) had 2 c.p. and blood and hematin in the simple, saccular gut. The gut bifurcated at 11 c.p. (6-9 days p.i.) (24 degrees C). The genital atrium, testes, ovary and vitellaria appeared at 16 c.p. (8-11 days p.i.), 22 c.p. (10-14 days p.i.), 30 c.p. (14-18 days p.i.) and 40 c.p. (17-21 days p.i.), respectively. Eggs were produced at 20 days p.i. The period from egg deposition to egg deposition is about one month at 24 degrees C.