Mortality, preference, avoidance, and activity of a predatory LeechExposed to cadmium.
The effects of cadmium on the hatching success of thecocoons of the freshwater predatory leech Nephelopsis obscura wereexamined together with the survivorship of hatchlings, changes in 96-hLC50 with biomass, preference-avoidance responses and changes inactivity. The 96-h EC50 for cocoons was 832.6 microg Cd/L with adecreasing bounded monotonic function best describing hatchling success as afunction of Cd concentration. Exposure of cocoons to Cd had a highlysignificant effect on post-hatchling survivorship with survivorship ofhatchlings from the 0-500-microg Cd/L concentrations not significantlydifferent from each other but higher than survivorship of hatchlings fromcocoons exposed to 1,000-4,000 microg Cd/L. Resistance to acute Cd toxicity,measured as LC50, increased with leech biomass. Inpreference-avoidance tests large leeches (>450 mg) spent more time in 100-and 200-microg Cd/L than in control water or in 50-microg Cd/L, while smallleeches (<250 mg) spent more time in 200-microg Cd/L compared to controlwater or 50-100-microg Cd/L. Leeches exposed to 100- and 200-microg Cd/Lexhibited a significant decrease in activity compared to the leeches in thecontrol and 50-microg Cd/L treatments.
Wicklum
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Division of Ecology, Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N 1N4, Canada.
Smith DEC
Davies
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RW
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D018533:Biomass; D002104:Cadmium / Q000633:toxicity*; D007865:Leeches / Q000187:drug effects* / Q000502:physiology; D009026:Mortality; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D014874:Water Pollutants, Chemical; D002104:Cadmium