Excess levels of nitrogen, phosphorus linked to deformed frogs
...e tadpole will turn into. By interfering with the tadpoles limb development, the parasite causes the frog to become deformed, often by making extra or missing limbs. This deformed frog is then prime prey for wading birds, such as herons or egrets, which the parasite needs for sexual reproduction. A...Nutrients cause increase in parasites and frog deformities
...t that excess nutrient inputs into the ponds where tadpoles develop causes an increase in rams horn snails - the exclusive first hosts for the parasites. Increased numbers of these snails correlate with higher levels of parasite infection and, in turn, frog deformities. These results may help to both explai...Dramatic decline of California native frog linked to introduced trout in mountain lakes
...trout are voracious eaters, quickly decimating the tadpoles in a lake. The delay in the decline of adult frogs...hey probably live 10 years or more, so the loss of tadpoles would not produce a dramatic drop in adult frogs for a decade or longer. As part of his study, he an...Out-of-balance ecosystems play role in demise of amphibian populations
...unctioning, he added. "The frogs that develop from tadpoles subsequently devour thousands of insects," he said...wed that about 16 percent of northern leopard frog tadpoles infected with Ribeiroia during the limb-bud stage had major deformities. However, when infected earl...... and when it killed nearly all of the thousands of tadpoles living in the last known breeding pond of the endangered Mississippi gopher frog. USGS scientist D. Earl Green is collaborating with scientists at the University of Virginia to classify and name the organism responsible for this disease. For more inf...Popular weed killer feminizes native leopard frogs across Midwest
... atrazine is used most. Atrazine may feminize male tadpoles and turn them into female frogs, he said, or it ma...males infertile. Alternatively, atrazine may favor tadpoles that delay sexual differentiation until after they've turned into frogs and leave the contaminated w...Study reveals clues to brain development
...ulation causes particular neurons in the brains of tadpoles to sprout new branches, and that such branching re...e of the members of their team. In one experiment, tadpoles were placed in a dark chamber for four hours and then moved into a chamber with a moving visual stim...Joint Genome Institute to sequence key African frog genome
...t for biologists because their growth from eggs to tadpoles to mature organisms sheds light on the processes that guide the development of cells and organs. X. tropicalis was chosen for sequencing because its genetic structure is similar to humans but smaller and easier to decode than that of other frog speci...Deformed frogs form when parasites and pesticides combine
...to survive. The researchers placed groups of their tadpoles in the six ponds within two kinds of enclosures lo...ode larvae to infect the tadpoles. The only tadpoles that developed limb deformities in the first experiment were those exposed to the trematode larvae, ...Deformed frogs form when parasites and pesticides combine
...re," Kiesecker says. The Kiesecker team collected tadpoles from ponds in Centre County, Pennsylvania, then used some of those tadpoles in a series of laboratory experiments and some in a series of field experiments conducted in six pon...Amphibians and crippling parasites
...ber of abnormalities, with more than 1000 abnormal tadpoles and young frogs found at 55 sites. When they co-occurred at an aquatic site, Pacific treefrogs exhibited more abnormalities than did western toads, marginally more than bullfrogs, and less than California newts. In order to understand if and why t...Popular weed killer disrupts frogs' sexual development
...vels often found in the environment demasculinizes tadpoles and turns them into hermaphrodites creatures with both male and female sexual characteristics. The herbicide also lowers levels of the male hormone testosterone in sexually mature male frogs by a factor of 10, to levels lower than those in normal fe...Popular weed killer demasculinizes frogs, disrupts their sexual development
...vels often found in the environment demasculinizes tadpoles and turns them into hermaphrodites - creatures wit... in a pond with estrogen, for example, all Xenopus tadpoles turn into females. In the presence of androgens, frogs grow larger voice boxes, or larynges. In labo...Scientists reveal role for nitric oxide during brain development
...ing nitric oxide levels in the developing brain of tadpoles significantly affects brain size and the number of brain cells. The study is significant because it is the first definitive demonstration of the essential role of nitric oxide during vertebrate brain development. Grigori Enikolopov, the principal inv...USGS: Contaminants may play important role in California amphibian declines
... They found that cholinesterase activity levels in tadpoles were significantly lower in the mountains east of ...olinesterase activity became decreasingly lower in tadpoles from both northern and southern sample sites as the sites moved in a gradient from the coast to the ...USGS diagnoses causes of many US amphibian die-offs
...s found dead in North Carolina; and from wood frog tadpoles and spotted salamanders found dead and dying at a Massachusetts site where several hundred to a thousand amphibians were reported to have died. For the second consecutive year, numerous frogs and salamanders at the Great Smoky Mountains National Par...X-ray studies shed light on frog deformities
... same time from a particular site, indicating that tadpoles at specific sites have received the same type of e...he same time from a particular site, it seems that tadpoles at a specific site have received the same type of developmental insult at the same stage of developm...Amphibian declines complicated, disturbing
...zers, the authors said. When exposed to them, some tadpoles and young frogs reduced their feeding activity, swam less vigorously, experienced disequilibrium, developed physical abnormalities, suffered paralysis and eventually died. And problems such as that, Blaustein said, may go even further. "The furor t...Fertilizers linked to amphibian deaths
...to moderate amounts of nitrates and nitrites, some tadpoles and young frogs reduced their feeding activity, sw... water killed over half of the Oregon spotted frog tadpoles after 15 days of exposure. All five species showed a similar level of mortality at levels of nitrite...Yale scientists find evidence healthy animals detect and avoid sick animals
...yof Sciences, said the authors found that bullfrog tadpoles were able to tellwhen others of their species were... a fungus that attacks thedigestive tract. Healthy tadpoles can become sick by spending time near infectedanimals. When presented with an infected bullfrog tadp...