title: The biology and the life history of Acanthocephalus clavula Dujardin, 1845 in Llyn Tegid (Bala Lake), North Wales
Creators: name: Rojanapaibul, A.
Publisher: name: University of Liverpool Repository
Year: 2023

description: The acanthocephalan, Acanthocephalus clavula Aujardin, 1845 is an inteatinal. _parasite of freshwater fir-he The iropod, Acellus neridianus Racovitza , is, an, intermediate host. The details of growth and development of A. clavula in A. ceridianue and Cottus robio (L. ) were described from laboratory experimental infection3... The complete life cycle required at least 132 days at 8-13°C; development, in intermediate host took 84 days, and 48, days were required for copulation and maturation in the, definitive, host. Temperature had direct effects on the. growth and development of, _the,. larval-parasite, by increasing the rate of development at, high, temperature (5-19°C). The growth and development of larval parasites in the intermediate host. was affected by crowding. Uniform growth and development were disturbed, if more than 3 ppranites were established in the same isopod.. ;&gt; wz The occurrence of A. clavula in gwyniad, roach, bullhead, eel was affected by a combination of one or more factors of the following: seasonal: iluetuationa, host sex, host length, hont age, feeding habits. The seasonal cycle of A. clavula wan clearly shown in gwyniad, androach4n Bala Lake. The parasites started to establish in late dummer and reached a peak in, Nay and June_in gwyniad and roach respectively, and declined thereafter. until the beginning of Coptember. The incidence of infection in, gwyniad was the same in the aale and female fish for. the, whole year. When the gwyniad data were summed into four 3-monthly periods, the incidence in, male gwyniad had aktendency to be lower than in femalen only during April-June. In roach, the incidence of infection was the same in males and females during April-June, and July-September, and the incidence in male fish was lower than females during October-December, and January-March. The incidence of infection in gwyniad increased with length and age of the fish over the whole year, but when the affect of seasonal fluctuation was minimized, the incidence of infection increased with length of fish. The intensity of infection in male gwyniad was lower :. hsr females from January to October, but much higher in November and December. In roach, the intensity of infection was always lower than 1. A. clavula was able to survive in all regions of the fish intestine, but it was seen that A. clavula established in a particular region of the intestine which was dependent on each host species. In gwyniad, the parasites were established 0-403 from anterior of the intestine; but in eel, the parasite was established 40-100% from anterior of the intestine. The experimental studies showed that superimposed infections occurred in both intermediate and definitive hosts. Overloaded superimposed infections may lead to the discharge of some worms. Host starvation did not cause any apparent discharge of worms from the fish. The shelled acanthors of A. clavula did not hatch in vitro using either wet and dry or applied pressure methods.The in survival times. of, ohelled acanthors and adults of A. clavula, were determined, but the results proved difficult to interpret.