Folivory and seasonal changes in diet in Rana hexadactyla (Anura: Ranidae)
ABSTRACT The autecology of Rana hexadactyla (Lesson) was studied at a seasonal locality in south India. The herbivorous larva transforms into an insectivorous frog, and a second dietary switch from insectivory to folivory occurs in adults, with plants constituting 79.5% of the diet, by volume. A variety of invertebrates and small vertebrates is consumed, especially by the adult females before the reproductive season. Larger frogs take larger animal prey and more prey types. Monthly figures of prey diversity generally show high values during the wet months.In Rana hexadactyla, the utilization of permanent waterbodies may help buffer the impact of the long dry seasons and, together with a supply of abundant food in the form of aquatic macrophytes, is thought to be linked to the capacity of the species to spawn three times a year.
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ABSTRACT: Herein, we analyzed microhabitat use, daily activity period, and diet of three populations of Rhinella ornata from three Brazilian Atlantic rainforest remnants: Estação Ecológica Estadual Paraíso (EEEP), Reserva Ecológica de Guapiaçu (REGUA), and Morro São João (MSJ). Leaf litter (35.2%) and bare ground (29.4%) were the microhabitats where most anurans were first sighted. Activity was predominantly nocturnal, and juveniles, opposed to adults, were active also during daylight. Diet was composed predominantly by arthropods, mainly Formicidae and Coleoptera. Isoptera was of relevance in the MSJ's population. The similarity of the trophic niche (Oij) of R. ornata between populations in terms of numerical proportion of food categories consumed was 0.999 between EEEP and REGUA, 0.523 between EEEP and MSJ, and 0.505 between REGUA and MSJ, and in terms of volumetric proportion was 0.689 between EEEP and REGUA, 0.300 between EEEP and MSJ, and 0.126 between REGUA and MSJ. The mean number and the mean volume of food items consumed per individual were higher in MSJ, and there was no difference between EEEP and REGUA. These differences might have occurred due to differences in prey availability among these areas. These results reveal some level of variability in prey types consumed among populations. The number of food items was related with the SVL in EEEP, and the jaw width affected the volume of food items ingested in the three populations studied. This may occur due to smaller-sized prey become energetically less favorable with increase of anurans' body size and also because smaller individuals are relatively constrained by jaw width. Flexibility in prey consumed may result in a low trophic similarity among different populations of R. ornata, and might represent an advantage in environments with varying prey availability.North-Western Journal of Zoology 01/2013; 9(1):157-165. · 0.70 Impact Factor
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ABSTRACT: We studied the diet of Leptodactylus ocellatus in a cacao plantation in southern Bahia state, Brazil and compared our results with data available from populations inhabiting natural and human modified habitats. Stomachs of 117 specimens were flushed whereby 77 stomachs revealed at least one prey item. Our results indicate that L. ocellatus consumes a great variety of food items at the study site, whereby Lepidoptera larvae, Coleoptera and Araneae dominated its diet. The presence of vertebrates including Teleostei and Anura in the diet revealed in previous studies was confirmed, although these items made up only minor parts of the diet. The index of relative importance showed that the diet of L. ocellatus was dominated by Lepidoptera larvae, followed by Coleoptera and Araneae. The Levins index observed in our samples was 8.51 and the standardized Shannon-Weaver index was 0.56. Apparently, the structure of the trophic niche of L. ocellatus is not affected by habitat alteration. The present study provides evidence for the opportunistic feeding behaviour and broad trophic niche breadth of L. ocellatus.
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ABSTRACT: We examined the food composition of the Marsh Frog, Pelophylax ridibundus Pallas 1771, population from Dobromir, Constanţa County, Romania. Stomach contents of 100 (27 juveniles, 10 ♂, 63 ♀) individuals were investigated. We found that the species mainly fed on terrestrial invertebrates preys belonging mostly to arthropod groups. The most frequently consumed were Curculionida and Carabida (50%), Araneida (46%) and Muscida (41%). There are differences in diet between sexes.