title: Mortality, preference, avoidance, and activity of a predatory LeechExposed to cadmium.
abstract: 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.
authors.affiliation: Division of Ecology, Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N 1N4, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Wicklum
authors.lastname: Smith DEC
authors.forename: R W
authors.initials: RW
authors.lastname: Davies
mesh_terms: 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*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium