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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

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Manfred Wanner; Effects of Light, Temperature, Fertilizers and Pesticides on Shell Size of the Common Freshwater and Soil Species Cyclopyxis kahli (Rhizopoda, Testacealobosia). Limnologica 24(4):333-338, 1994

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A clone of the testate amoebae Cyclopyxis kahli Deflandre was used to test the impact of environmental factors (food, temperature, light, mineral fertilizer, lime, insecticides) on shell size under controlled laboratory conditions. Individuals kept at 17 degrees C and provided with food in surplus had larger shells than individuals kept at 21 degrees C and sparse food supply. Direct effects of lime or mineral fertilizer on shell size were not detected, while the two insecticides (pyrethrum, cypermethrin) influenced it significantly, but not consistently. Interactions between different treatments occured frequently. For example, food and temperature influenced shell size to a greater extend than treatments with insecticides. Combined administrations of lime, fertilizer and insecticides affected shell size in the same way as insecticides alone. The investigated clone showed a high variability in culture growth as well as in shell size under changed environmental conditions. This confirms results of previously conducted experiments with C. kahli (Wanner & Meisterfeld 1994; Wanner et al. 1994), which revealed consequences for taxonomical work based on shell characteristics and new feasibilites in bioindications.