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Difference in the sensitivity to chemical compounds between female and male neonates of Daphnia magna
Author(s) -
Ikuno Erika,
Matsumoto Takeru,
Okubo Tomohiro,
Itoi Shiro,
Sugita Haruo
Publication year - 2008
Publication title -
environmental toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.813
H-Index - 77
eISSN - 1522-7278
pISSN - 1520-4081
DOI - 10.1002/tox.20403
Subject(s) - daphnia magna , potassium dichromate , toxicity , pentachlorophenol , offspring , ecotoxicology , paraquat , toxicology , daphnia , biology , physiology , chemistry , endocrinology , medicine , environmental chemistry , biochemistry , crustacean , zoology , pregnancy , inorganic chemistry , genetics
Daphnia magna usually produce female offspring by parthenogenesis, and thus only female neonates are used to evaluate the environmental toxicity to chemicals. Additionally, it is known that male daphnids are induced by exposure to a juvenile hormone, methyl farnesoate, during late ovarian development. In this study, we investigated the concentration of methyl farnesoate in a 24‐h exposure producing 100% males, and the difference in sensitivity to chemical compounds, potassium dichromate, pentachlorophenol, and paraquat, between females and males, referring to OECD Test Guideline 202. The results show that the minimum concentration for 100%‐male induction of methyl farnesoate in adult females was 50 μg/L. In addition, acute toxicity tests (immobility test) with the other chemicals showed that male neonates have higher tolerance to potassium dichromate and pentachlorophenol than females for at least 24 h after birth, while no sex difference was observed in the sensitivity to paraquat. The differences in the median effective concentrations in these compounds between female and male neonates suggest two different overall modes of action. Using female daphnids for environmentally toxicity testing seems reasonable, since the females are more sensitive to chemicals than males. Furthermore, the method of male induction established in this study could be used for screening of endocrine disruptors. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008.