engleski

Effects of pesticides on frogs' eggs

Amphibians are very susceptible to various threats posed by the environment. Sometimes, even the slightest change can cause measurable shifts in population dynamics. Environmental stress, such as stress caused by pesticides, can result in changes in population characteristics (mostly negative ; decrease of abundance to extinction). Although it is known that pesticides can negatively affect freshwater fauna, little is known on the effects of pesticides on frogs’ eggs since they are generally considered to be well protected by gelatinous substance surrounding the embryos. Thus, the purpose of our research was to examine the influence of three commonly used pesticides, dimethoate, glyphosate and pirimiphos‐methyl on eggs of agile frog, Rana dalmatina. We tested the influence of a one‐ time exposure, at the beginning of the experiment, of environmentally relevant concent rations of the aforementioned pesticides on the agile frogs’ eggs, and we measured time to hatching and hatching rate/mortality. Each pesticide was used in two replicates, with 200 tadpoles in each tank. We also monitored the survival rate and body size of hatched tadpoles in comparison to the control group. The number of tadpoles hatched differed significantly between the pesticides and the control group, but also between different pesticides. The lowest hatching and survival rate was found with herbicide glyphosate, while insecticide pirimiphos‐methyl had the lowest impact of all the examined pesticides.

Amphibia; Anura; Rana dalmatina; pesticides

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