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Metazoan parasites of killifish from Mosambique



Druh Další prezentace na konferencích
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Popis In this study, we examined 205 specimens of four annual killifish species (Nothobranchius orthonothus, N. furzeri, N. kadleci and N. rachovii) from 14 different localities in south part of Mosambique to study their metazoan parasites and to find factors responsible for differences in intra-specific and inter-specific variation of parasite infection. Killifish of the genus Nothobranchius (Cyprinodontiformes, Nothobranchiidae) are small annual fish inhabiting ephemeral rain-fed savannah pools of east Africa. Their life span is very short. It is limited to several months until the pool dries. In that time the fish have to grow, mature and reproduce. The only stage surviving the dry season is the dormant egg buried in the dry substratum, waiting for the onset of the annual rains that fill the pool and enable hatching. The populations are strictly separated, young fish thus cannot obtain parasites directly from parental population. We recorded 17 parasite taxa. Except for two individuals of leech all parasites were endoparasites. Trematode larval stages, metacercariae, were the most abundant parasites, with 75 % prevalence. They infected mainly muscle of fish, often in high abundances (up to 807 individuals per host). Also cestodes and nematodes were often found in killifish. Except the trematode Emoleptalea sp. in the intestine, all parasites were larvae, indicating the killifish may be the important intermediate hosts. There was no difference in parasite species richness and total abundance between killifish species. The species do not differ in spatial distribution and trophic demands, the exposure to parasites is thus similar. The parasite species richness was positively associated with size of the pool and, to a smaller extent, with the amount of grass littoral vegetation. Larger pools enable the existence of different habitats attractive for a variety of parasite´s intermediate hosts serving as a source of killifish infection . Larger sites may also attract bird definitive hosts that can excrete the eggs of parasites.
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