| Endosulfan Exposure Disrupts Pheromonal Systems in the Red-Spotted Newt: A Mechanism for Subtle Effects of Environmental Chemicals Daesik Park, Steven C. Hempleman, and Catherine R. Propper Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA Abstract
Because chemicals introduced into the environment by humans can affect both long-term survivorship and reproduction of amphibians, discovering the specific mechanisms through which these chemicals act may facilitate the development of plans for amphibian conservation. We investigated the amphibian pheromonal system as a potential target of common environmental chemicals. By treating female red-spotted newts, Notophthalmus viridescens, to a commonly used insecticide, endosulfan, we found that the pheromonal system is highly susceptible to low-concentration exposure. The impairment of the pheromonal system directly led to disrupted mate choice and lowered mating success. There were no other notable physiologic or behavioral changes demonstrated by the animals at the insecticide concentrations administered. Our findings suggest that the amphibian pheromonal system is one of the systems subject to subtle negative effects of environmental chemicals. Key words: amphibian declines, electro-olfactogram, endosulfan, environmental chemicals, insecticides, pheromones, olfaction. Environ Health Perspect 109:669-673 (2001) . [Online 22 June 2001] http://ehpnet1.niehs.nih.gov/docs/2001/109p669-673park/ abstract.html Address correspondence to D. Park, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011-5640, USA. Telephone: (520) 523-1344. Fax: (520) 523-7500. E-mail: daesikpark@hotmail.com We thank K.C. Nishikawa, L.C. Drickamer, L. Rania, L. Mayer, S. Overstreet, and M. Minor for their help during experiments and for their useful comments on early versions of the manuscript. C.A. Dyer kindly provided antiserum for the radioimmunoassay. This study was supported by the Council for Tobacco Research, USA (grant 4661R1 to C.R.P.) and by the International Rotary Foundation (D.P.) . Received 13 November 2000 ; accepted 2 February 2001.
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