Christine Dell'Amore
National Geographic News <http://news.nationalgeographic.com> Published December 3, 2010 Male birds that eat mercury-contaminated food show "surprising" homosexual behavior, scientists have found. In a recent experiment in captive white ibises, many of the males exposed to the metal chose other males as mates. These "male-male pairs did everything that a heterosexual pair would do," said study leader Peter Frederick <http://www.wec.ufl.edu/faculty/frederickp/> , a wildlife ecologist at the University of Florida in Gainesville. "They built their nest, copulated together, stayed together on a nest for a month, even though there were no eggs-they did the whole nine yards." .. http://news.nationalgeographic.com/news/2010/12/101203-homosexual-birds-merc ury-science/ Proceedings of the Royal Society B: Biological Sciences, published online December 1, 2010 Altered pairing behaviour and reproductive success in white ibises exposed to environmentally relevant concentrations of methylmercury 1. <http://rspb.royalsocietypublishing.org/search?author1=Peter+Frederick&sorts pec=date&submit=Submit> Peter Frederick <http://rspb.royalsocietypublishing.org/content/early/2010/11/24/rspb.2010.2 189.abstract?sid=4c63cdc0-93a4-4c67-8633-75275cbcfed5#aff-1> 1, <http://rspb.royalsocietypublishing.org/content/early/2010/11/24/rspb.2010.2 189.abstract?sid=4c63cdc0-93a4-4c67-8633-75275cbcfed5#corresp-1> * and 2. <http://rspb.royalsocietypublishing.org/search?author1=Nilmini+Jayasena&sort spec=date&submit=Submit> Nilmini Jayasena <http://rspb.royalsocietypublishing.org/content/early/2010/11/24/rspb.2010.2 189.abstract?sid=4c63cdc0-93a4-4c67-8633-75275cbcfed5#aff-1> 1, <http://rspb.royalsocietypublishing.org/content/early/2010/11/24/rspb.2010.2 189.abstract?sid=4c63cdc0-93a4-4c67-8633-75275cbcfed5#aff-2> 2 1. 1Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA 2. 2Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, Peradeniya, Sri Lanka 1. * Author for correspondence ( <mailto:[email protected]> [email protected]). Abstract Methylmercury (MeHg) is the most biologically available and toxic form of mercury, and can act as a powerful teratogen, neurotoxin and endocrine disruptor in vertebrates. However, mechanisms of endocrine impairment and net effects on demography of biota are poorly understood. Here, we report that experimental exposure of an aquatic bird over 3 years to environmentally relevant dietary MeHg concentrations (0.05-0.3 ppm wet weight) resulted in dose-related increases in male-male pairing behaviour (to 55% of males), and decreases in egg productivity (to 30%). Dosed males showed decreased rates of key courtship behaviours, and were approached less by courting females in comparison to control males. Within dosed groups, homosexual males showed a similar reduction when compared with dosed heterosexual males. We found an average 35 per cent decrease in fledgling production in high-dose birds over the study duration. These results are of interest because (i) MeHg exposure is experimentally tied to demographically important reproductive deficits, (ii) these effects were found at low, chronic exposure levels commonly experienced by wildlife, and (iii) effects on reproductive behaviour and sexual preference mediated by endocrine disruption represent a novel and probably under-reported mechanism by which contaminants may influence wild populations of birds. ---- Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net Archives: http://lists.umn.edu/archives/mou-net.html
