PITTSBURGH -- Amphibians exposed to insecticides early in lifeeven those not yet hatchedhave a higher tolerance to those same insecticides later in life, according to a recent University of Pittsburgh study.
Published in Evolutionary Applications, the Pitt study found that wood frog populations residing farther from agricultural fields are not very tolerant to a particular type of insecticide, but they can become more tolerant with early exposure.
"This is the first study to show that tadpole tolerance to insecticides can be influenced by exposure to insecticides extremely early on in lifein this case, as early as the embryonic stage," said study principal investigator Rick Relyea, Pitt professor of biological sciences within the Kenneth P. Dietrich School of Arts and Sciences and director of the University's Pymatuning Laboratory of Ecology.
"Amphibian populations are declining worldwide, and pesticides and insecticides are one hypothesized cause," said Jessica Hua, lead author of the paper and a PhD candidate studying biological sciences in Relyea's laboratory. "So this discovery has promising implications for the persistence of amphibian populations."
The Pitt teamwhich also included Nathan Morehouse, Pitt assistant professor of biological sciencesexamined three potential factors that might allow larval wood frogs to have a high tolerance to the insecticide: the concentration of the initial insecticide exposure, the timing of the exposure, and the population's history of exposure. They chose to work with carbaryl, a popular household insecticide that also is used for malaria prevention.
The researchers conducted experiments with both embryos and hatchlings that were collected as newly laid eggs from four Pennsylvania pondstwo near agricultural fields and two farther away. Both embryos and hatchlings from all four environs were first exposed to a low, nonlethal concentration of the insecticide. Later, they e
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University of Pittsburgh