On the trophic spectrum of <i>Pelophylax ridibundus</i> (Pallas, 1771) (Amphibia: Anura: Ranidae) in western Iran

<p>Using the stomach flushing technique, a total of 188 specimens of the Marsh Frog, <i>Pelophylax ridibundus</i>, were flushed, of which 129 had at least one food item in the stomach. The diet consisted of Annelida, Mollusca, Arthropoda and Chordata with Arthropoda being the most abundant group. Both diet volume and number of food items per stomach were significantly larger in April than in August. The proportion of frequency of occurrence (FOi%) of food categories did not show a constant food item in flushed materials. <i>Pelophylax ridibundus</i> prefers Diptera, Coleoptera, Amphipoda and Hymenoptera over other food categories. The Index of Relative Importance (IRI) for food categories differs between sexes and seasons. Differences were found in the food volume and the number of food items between seasons, but not between sexes. Prey volume is positively correlated with frog size.