Effect of Ammonium Nitrate on the cannibalism of Marsh frog, Pelophylax sp. (Anura: Ranidae)

In recent decades, the use of nitrogen-based fertilizers such as ammonium nitrate has grown significantly in agricultural use. Many amphibian species use agricultural lands as a place to live and reproduction, and as a result are constantly exposed to this chemical fertilizer. This pollutant has negatively affected many biological variables of amphibians, including growth, development and survival, but there is very little research on its effect on cannibalism. In this study, we investigated the effect of ammonium nitrate on cannibalism of larval Marsh frog, Pelophylax sp. in north and northeast of Iran. For this purpose, 360 larval of Marsh frog with a density of 20 and water volume of 1500 ml per container, in three replications at concentrations of 0 (control), 5, 10, 20, 30 and 40 mg/l, with an average temperature of 28 °C, conducted for 143 days. According to the results, the start of cannibalism of Marsh frog larvae was recorded at week 8 and the end of cannibalism at week 17. The highest and lowest percentages of cannibalism were measured in the control treatment (31.66% ±25.65) and the concentration of 40 mg /l (0%), respectively. Based on one-way analysis of variance, with increasing the concentration of ammonium nitrate, the percentage of cannibalism decreased significantly (p=0.05).