A comparative study of insecticide toxicity among seven cladoceran species

Abstract

The sensitivities of seven cladoceran species (Ceriodaphnia reticulata, Chydorus sphaericus, Daphnia galeata, Diaphanosoma brachyurum, Moina macrocopa, Scapholeberis kingi, and Simocephalus vetulus) to carbamate insecticides (carbaryl and methomyl) were investigated by acute toxicity tests. The sensitivities to carbaryl and methomyl were highly correlated among the tested organisms, but the co-tolerance level varied markedly among species. C. reticulata showed the highest sensitivity, whereas M. macrocopa and S. kingi showed the lowest sensitivities to the two insecticides. These results indicate that the degree of chemical impacts on natural communities can vary depending on cladoceran species composition. The highly positive correlation between the EC(50) values for both insecticides indicates that the two chemicals have a shared mode of action on cladoceran species. Unlike previous reports, acute toxicity was not correlated with body size. The results are discussed in relation to community-level experiments, the functions of freshwater ecosystems, and ecological risk assessment.

Evaluation of the risk of mixtures of paddy insecticides and their transformation products to aquatic organisms in the Sakura River, Japan

“…The reason for the selection of D. magna is as follows: the test species D. magna were more sensitive than two riverine cladocerans to carbaryl and methomyl insecticides [24], and the test species are good representatives of sensitive species in the field [25]. Daphnia magna were obtained from the National Institute for Environmental Studies, Tsukuba, Japan.…”

Assessment of the effect of a commercial formulation of Methomyl on reproduction of Daphnia obtusa Kürz (1874)

“…The cladoceran Daphnia magna is very sensitive to the chemical with a CL 50-48h of 32 mg L -1 and a chronic maximum acceptable concentration in the range of 1.6 to 3.5 mg L -1 for other species (WHO, 2004;Pereira & Goncalves, 2007). Mano et al (2010) reported that sensitivities to Methomyl were highly correlated among cladoceran species, but the co-tolerance level varied markedly among species. Ceriodaphnia reticulate showed the highest sensitivity, whereas Moina macrocopa and Scapholeberis kingi showed the lowest sensitivity.…”

Comparison of acute toxicity of two neonicotinoid insecticides, imidacloprid and clothianidin, to five cladoceran species

“…In parallel with the bioassays, to evaluate the relationship between the acute concentration of clothianidin to test cladocerans and their body sizes, we measured the body lengths of 30-50 female neonates of each species randomly selected. Body lengths, from the crown of the head to the base of the tail spine, 18,23) were measured using a dissecting microscope (Leica DFC490, Leica, Wetzlar, Germany).…”

“…to other toxicants, such as mercury, zinc, and carbamate insecticides, has also been reported. 23,33,34) On the other hand, Wu et al 29) have indicated that the test organisms and protocols accepted by regulating authorities, such as OECD, do not always reflect local taxa or site-specific conditions, whereas Hose and van den Brink 35) have reported that the sensitivity of organisms to toxicants is independent of their geographic origin. Among the cladocerans used in this study, neither C. dubia nor D. magna are indigenous species in Japan.…”

“…Among the cladocerans used in this study, neither C. dubia nor D. magna are indigenous species in Japan. In this context, C. reticulata, which plays an important role in energy flow in aquatic ecosystems and environments through the microbial loop, 23) can be a more suitable ecotoxicological test species for the freshwater environments of Japan.…”