ISSN:
1573-5117
Schlagwort(e):
fairy shrimp
;
zooplankton
;
prey size
;
prey density
;
electivity index
;
filtration rate
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract Laboratory cultured Streptocephalus proboscideus (three sizes (mm), viz. 8.44 ± 0.95 (virgin), 14.18 ± 1.49 (adult I) and 19.24 ± 1.52 (adult II)) were offered (separately for males and females) field collected zooplankton (12 prey types) at three levels of abundance (1.0 ml−1, 2.0 ml−1 and 4.1 ind. ml−1 in 30-minute feeding experiments. Gut contents, analyzed for abundance and diversity of prey type, showed that predator size, sex and their interaction had strong effects on prey consumption. Regardless of their size, and of prey density, S. proboscideus females consumed 25–90% more prey than males. Their filtration rates (adult II) were higher (125 ml ind.−1 h.−1) than those of males (30 ml ind.−1 h.−1) too. Rotifers had the highest numerical percentage in the gut, regardless of predator size or sex. Cladocerans were only consumed by adults I and II. Adult II females consumed 28.5–43.3 µg zooplankton dry weight ind.−1 h.−1. Size distribution of B. longirostris in the field and in the gut were closely similar. This study confirms S. proboscideus as a non-selective filter feeder. Since it did not eat jumping rotifers, copepod nauplii and copepodites, it may contribute to structuring its prey communities, because good escapers will be enriched in the medium, while poor escapers will be depleted.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00013732
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