The Ecology of Neoechinorhynchus rutili (Muller)

Seasonal occurrence and maturation ofNeoechinorhynchus rutili(Acanthocephala) in barbel,Barbus barbus(Pisces), of the Jihlava River , Czech Republic

“…3); this reflects also in the higher values of prevalence and mean intensity in February and March (Fig. 2) In contrast to observations by Walkey (1967) and Bibby (1972), who reported the prevalence and mean intensity of N. rutili to be decreased in the winter and increased in the summer, the results of the present study are quite opposite : the highest prevalence was found in February-March and the lowest in July, whe reas the lowest mean intensity in July. The highest values of N. rutili prevalence in winter were also recorded by Valtonen (1979) and Valtonen and Crompton (1990) in Coregonus widegreni and Gymnocephcilus ceruuus in the Bothnian Bay in Finland.…”

“…In this study, a distinct dependence of the prevalence and mean intensity of N. rutili infection on the body size (age) of barbel was recorded, when the highest values were found in the largest fish. The same was observed by Walkey (1967) and Bibby (1972) in the hosts Gasterosteus aculeatus and Phoxinus phoxinus, respectively. In contrast.…”

“…3) These fluctuations appear to be closely associated with the parasite's seasonal cycle of maturation. (Brady, 1910;Jarecka, 1956;Styczynska, 1958;Merrit and Pratt, 1964;Walkey, 1967;Valtonen, 1979 attaining their minima in July (Fig. 3).…”

“…1953;Lassiere and Crompton, 1988), various species of ostracods (Ostracoda) (Brady, 1910;Jarecka. 1956;Styczynska, 1958;Merrit and Pratt, 1964;Walkey, 1967;Valtonen, 1979), and from crayfish Pacifastacus trowbridgi (Merrit and Pratt, 1964 et al (1980) and Zelinka et al (1984).…”

The life cycle and seasonal changes in the occurrence ofPomphorhynchus laevis(Palaeacanthocephala, Pomphorhynchidae) in a small isolated lake

“…Despite this, the relative decrease of the male frequency occurring in winter and summer months predominantly for Gammarus suggests a higher sensibility of male larvae to the seasonal changes of environmental conditions for the worse (frozen or drying lake). In a lesser degree, winter and summer decrease of the adult males frequency occurred also in minnow, that has previously been observed also in Acanthocephalus lucii (Brattey, 1988) 1967;Tedla & Fernando, 1970;Brattey, 1988;Molloy et al, 1995). Thus, mature females producing high numbers of eggs (shelled acanthors) occurred most frequently in July (Fig.…”