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Common pesticide changes male frogs into females, likely devastating populations Jeremy Hance mongabay.com March 01, 2010 To study how atrazine impacts frogs, researchers studied the long-term effects of the pesticide on an all-male group forty of African clawed frogs (Xenopus laevis). Even though they exposed the frogs to a low doze (2.5 parts per billion, i.e. ppb) of the pesticide, the researchers found that 10 percent of the animals became full-fledged females due to exposure to the pesticide, capably even of breeding successfully with males. The other 90 percent of the exposed males were demasculinized, suffering from decreased testosterone, low fertility, and an inability to outcompete non-exposed males in breeding.
According to the paper: "atrazine is the most commonly detected pesticide contaminant of ground, surface, and drinking water" due to its popularity. Eighty million pounds are used annually in the United States alone with rainfall spreading the pesticide far beyond its application point. Worldwide amphibians are in decline: at least one third of the world's amphibians are currently threatened with extinction, and researchers estimate that over 120 amphibian species have gone extinct in just thirty years. While scientists have paid a lot of attention to particular threats such as habitat loss, climate change, and a fungal disease that is known to wipe-out whole amphibian populations, far less attention has been given to the possible role of pesticides, like atrazine. "The present study suggests several ways that exposure to endocrine disruptors such as atrazine may lead to population level effects in the wild and contribute to amphibian declines," the researchers write. "Certainly, the inability to compete for females and the significant decline in fertility in exposed males, as reported in the present study, will have a direct impact on exposed populations." In addition, male frogs that become wholly female due to the pesticide can only in-turn produce male young. The researchers say that mathematic modeling proves such a situation could lead to the eventual extinction of an entire species. But it's not just amphibian survival that is at stake, past studies have shown atrazine to be a potent endocrine disrupter in fish, reptiles, birds, rodents, and even human cell lines. Atrazine was banned in the EU in 2004, but remains widely used in the US and around the world. Citation: Tyrone B. Hayes, Vicky Khoury, Anne Narayan, Mariam Nazir, Andrew Park, Travis Brown, Lillian Adame, Elton Chan, Daniel Buchholz, Theresa Stueve, and Sherrie Gallipeau. Atrazine induces complete feminization and chemical castration in male African clawed frogs (Xenopus laevis). PNAS. Related articles Scientists uncover mystery of how frog plague kills its victims (10/22/2009) One hundred and twenty species of frogs are reported to have gone extinct since 1980 (although the number is likely even higher). While devastated by habitat loss, pollution, and climate change, a baffling disease may be the biggest factor behind the alarming extinctions of frogs. Called chytridiomycosis, the disease is caused by the microscopic fungus Batrachochytrium dendrobatidis which kills its tiny victims indiscriminately. Freshwater species worse off than land or marine (10/15/2009) Scientists have announced that freshwater species are likely the most threatened on earth. Extinction rates for freshwater inhabitants are currently four to six times the rates for terrestrial and marine species. Yet, these figures have not lead to action on the ground. Save the frogs, save ourselves 
(09/04/2009) Amphibians are going extinct around the globe. As a scientist specializing in frogs, I have watched dozens of species of these creatures die out. The extinction of frogs and salamanders might seem unimportant, but the reality couldn't be farther from the truth. Indeed, from regulating their local ecosystems, to consuming and controlling the population of mosquitoes and other insects that spread disease, to potentially pointing the way to new drugs for fighting diseases such as cancer or HIV-AIDS, the fate of these creatures is inexorably linked to our own.
Amphibians could develop immunity against devastating fungal disease (04/03/2009) The fungal disease chytridiomycosis has ravaged amphibian populations, including contributing to several extinctions. But new research may bring some hope for currently threatened amphibians. Salamander populations collapse in Central America (02/09/2009) Salamanders in Central America — like frogs, toads, and other amphibians at sites around the world — are rapidly and mysteriously declining, report researchers writing in the journal Proceedings of the National Academy of Sciences. Disturbingly, salamanders are disappearing from protected areas and otherwise pristine habitats. One billion frogs harvested as food per year (01/21/2009) The consumption of up to one billion frogs per year to satisfy human appetite for frog flesh is adding to the litany of pressures on global amphibian populations, write researchers in the upcoming issue of Conservation Biology. (12/01/2008) The Neotropics harbor between 30-50% of the world's reptiles and amphibians, but dramatic declines in both groups have been observed over recent decades. While a number of factors have been cited, many of the causes of reptile and amphibian declines are still poorly understood. The situation is paralleled by a lack of information of the natural history, ecology, and behavior of many species. New hope of curing amphibian plague (11/28/2008) Amphibians worldwide are in trouble. One of the most endangered animal groups, amphibians are increasingly threatened by habitat loss, pollution, and climate change. However the largest threat is chytridiomycosis, a devastating disease caused by a parasitic chytrid fungus known as Batrachochytrium dendrobatidis, otherwise known as Bd. Scientists can't explain cause of amphibian extinction crisis (11/13/2008) Scientists have yet to conclusively explain the underlying cause of global declines in amphibian populations, according to a study published in the journal Proceedings of the National Academy of Sciences. The research says that two leading theories for the demise of amphibians — both related to the emergence and spread of the deadly chytrid fungus — are not supported by scientific data.
Tags: amphibians amphibian crisis frogs united states europe pollution strange extinction agriculture farming jeremy hance green environment Animal behvaior Environmental Law animal behavior animals biodiversity conservation ecology endangered species herps in-situ conservation health rainforest animals saving species from extinction wildlife News index | RSS | News Feed | Twitter | Home Advertisements: Organic Apparel from Patagonia | Insect-repelling clothing
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