|Abstract or Summary
- The life cycle of a monogenean, Diclidophora sp., was studied
with special attention to the time required for developmental stages
to occur. Eggs are produced by adult worms at the rate of one every
13.5 minutes and require 32 days to hatch when incubated at 12.5°C
and 30.9‰ salinity. Rate of development and hatching success are
strongly dependent on incubation temperature and salinity.
Growth and development of the larval stages are similar to
other known species of the family Diclidophoridae. The presence
in the oncomiracidium of a precocious set of attachment clamps and
the premature loss of larval hooks distinguish it from related species.
Oncomiracidia survive approximately 36 hours if no host fish is
Larvae attach to the inner lateral borders of primary lamellae
of the host fish gill. A second set of clamps is added before the 36th
day, the third set soon after the 44th day, and the last pair by the 58th
day. Sexual maturity is reached by the 153rd day after hatching.
Experimental infections were maintained on redtail surfperch for
Naturally infected redtail surfperch, silver surfperch and
walleye surfperch were collected. Rates of infection with Diclidophora
were 38.5%, 50.0%, and 8.0%, respectively. Multiple infections
were common. Female redtail surfperch were less often infected
than were males. Age-dependent immunity was not observed. Both
sexes demonstrated a positive correlation between the rate of infection
and age of fish. White seaperch, shiner perch, pile perch and striped
seaperch were not naturally infected.
Redtail, silver, and walleye surfperch and white seaperch were
experimentally infected and normal development of worms on these
fish was observed.
Oncomiracidia of Diclidophora sp. were exposed to various concentrations
of blood serum and body mucus from redtail surfperch
and striped seaperch, and their responses were observed. Oncomiracidia
were more strongly affected by materials from the striped
perch than from redtail surfperch. In both species mucus affected
the oncomiracidia more strongly than blood serum.
Adult worms were more severely injured by exposure to high
concentrations of striped perch mucus or serum than by exposure to similar concentrations of redtail mucus or serum.
Ring tests, Ouchterlony gel diffusion and passive hemagglutination
tests were used to determine whether antibodies produced by
striped perch were responsible for preventing attachment and growth
of Diclidophora sp. Ring tests were negative, gel diffusion tests
demonstrated very weak antibodies in both redtail surfperch and striped
seaperch mucus. Passive hemagglutination experiments indicated
weak antibodies to Diclidophora sp. in mucus and serum of redtail
surfperch and in serum of striped seaperch. Mucus from the later
species demonstrated recognizably stronger antibody titers. Mucus
of both fish species contain weak concentrations of non-specific antibodies.