Diet of three sympatric Physalaemus (Anura: Leptodactylidae) from the Brazilian semiarid region (original) (raw)
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Herpetology Notes, 2017
Comparative studies of the diet of ecologically and phylogenetically close-related species assist in understanding the evolutionary processes underlying feeding specialization. The frogs Physalaemus lisei (Braun’s Dwarf Frog) and P. gracilis (Graceful Dwarf Frog) are good models for comparative diet studies because they occur in sympatry in several forest environments of Brazil. In this study we evaluated the gastrointestinal content of 83 individuals of these two species. We registered 12 prey categories in the diet of P. gracilis, and 19 in the diet of P. lisei. Formicidae was the most important prey category in the diet of both species, followed by Coleoptera and Araneae. Despite the high importance of ants in the diet of both species, as assessed by the Index of Relative Importance, Coleoptera presented the highest volumetric contribution. Both species presented a similar trophic niche breadth and a high diet overlap. Our results indicate similarities in the diet composition and foraging behavior of P. lisei and P. gracilis.
Diet of the Neotropical frog Leptodactylus mystaceus (Anura: Leptodactylidae)
Leptodactylus mystaceus is distributed throughout Brazil and no information is available about its diet. Here, we analyzed the diet of L. mystaceus from Novo Progresso, Pará, Brazil. We extracted the stomachs of 25 specimens. For each prey category, we calculated the frequency (Fi%), volume (Vi%) and Feeding Index (IAi). Among the specimens analyzed, seven (28%) had empty stomachs and the other ingested eight prey categories (Araneae, Blattodea, Coleoptera, Dermaptera, Diptera adults, Diptera larva, Formicidae, and Lepidoptera), and large amounts of plant material. This suggests that L. mystaceus is a generalist species and Dermaptera was the most representative component of its diet.
Acta Herpetologica, 2023
Despite the current increase in studies on the diet of neotropical anurans, few of them take a comparative approach between syntopic species. The objective of this study was to compare the diet of four syntopic species of the genus Physalaemus. The collections occurred between November 2014 and January 2016 in a preserved area of the subtropical Atlantic Forest in southern Brazil. We compared the gastrointestinal content of 109 individuals distributed in the species Physalaemus biligonigerus, P. cuvieri, P. gracilis and P. henselii. We measured the Index of Relative Importance of each prey category and calculated trophic niche breadth using the Levins’ index (Bsta) and trophic niche overlap using the Pianka’s index (Ojk). We also applied compositional analysis to evaluate feeding specializations. Formicidae was the most important prey category for P. biligonigerus (IRI = 88.5%) and P. gracilis (IRI = 39.1%). For P. henselii and P. cuvieri, the most important category was Isopoda (IRI = 51.7% and 57.9%, respectively), followed by Formicidae (IRI = 34.9% and 24.8%). Isopoda was also important in the diet of P. gracilis (IIR = 28.6%), followed by Araneae (IIR = 22.6%). The trophic niche breadth of the four species was narrow, all smaller than 0.32, and the lowest was recorded for P. biligonigerus (0.04). The trophic niche overlap was higher between P. biligonigerus and P. cuvieri (96%), and between P. gracilis and P. henselii (95%). Only P. gracilis presented a significant level of feeding specialization. The differences in their diets suggest different uses of the resources, which could relate to different ways of exploring the microhabitat.
Herpetology Notes, 2015
Physalaemus Fitzinger, 1826 is the most speciose genus of Leiuperinae frogs, with more than 40 recognized species. They are widely distributed in the Neotropical region, especially in open areas, and are among the most abundant species in several anuran communities. Nevertheless, our comprehension of the diet composition and trophic relationships of these species remains poor. In this study, we describe and compare the diet of sympatric and syntopic populations of Physalaemus gracilis and P. biligonigerus that inhabit the southernmost coastal zone of Brazil. The stomach content analyses revealed 13 distinct prey categories in the diet of P. gracilis and 12 in the diet of P. biligonigerus. On one hand the diet compositions of the species were significantly different according to both numeric and volumetric evaluations. On the other hand, Coleoptera and Formicidae were the most important prey for both species. The niche breadth was higher for P. gracilis than P. biligonigerus, and niche overlap was relatively low for both species (28%). Our results indicate that P. biligonigerus has a less generalist diet than P. gracilis, with a remarkable consumption of ants. Although both species are morphologically similar and sympatric, they appear to present different feeding strategies or preferences based on the low values of niche overlap.
Studies on Neotropical Fauna and Environment, 2004
Leptodactylus ocellatus (LO) and L. labyrinthicus (LL) are known to prey on other frogs. Here we compare their food habits based on the analysis of stomach contents and their spatial distribution when in sympatry. LO was found most frequently near stream banks, and LL on the margins of lakes and ponds. LO was found within 10 m of permanent water bodies; LL frequently used ponds far from lakes and rivers. Coleoptera, Formicidae, and Isoptera comprised 52% of the prey types identified in the LO sample, whereas Coleoptera and insect larvae represented 58% of the prey items of LL. Frogs were not frequent in the diet of either species but, in volume, represented the second most important category for LO and the first for LL. LO showed a larger trophic niche breadth than LL. The trophic niche overlap between the two species was 68.3% for percentage of prey items. The present work confirms the relative importance of frogs in the diet of both species. The greater capacity of LL in moving far away from permanent water bodies may generate better opportunities for prey selection and a narrower trophic niche breadth. The large range of prey used by these two species indicates they are generalist/opportunistic feeders.
Rev. Esp. Herp, 2004
The foraging strategies of amphibians allow them to capture a wide variety of prey, diet variation being generally associated with morphological, physiological, and behavioral traits that facilitate the location, identification, and digestion of food items. Herein we present the diet composition of L. podicipinus and variations regarding the number and type of prey consumed by juveniles, males and females during the wet and dry seasons, in the southern Pantanal, Brazil. Sampling was conducted at three different times during the dry season, and three different times during the wet season between June 1998 and May 1999. The quantitative analysis showed that the diet of L. podicipinus is composed mainly by Coleoptera (51.0%), Hymenoptera (9.1%), Diptera (8.7%), Aranae (5.3%), and Orthoptera (4.7%). In the wet season, males captured more prey than juveniles and females, but in the dry season there were no differences. Males and females ingested larger prey compared to juveniles. The frog L. podicipinus is an opportunist and generalist predator, and the availability of prey in the environment may be an important factor determining its diet composition in the Pantanal.
Diet of the South American frog Leptodactylus ocellatus (Anura, Leptodactylidae) in Uruguay
Iheringia. Série …, 2004
The diet of Leptodactylus ocellatus (L., 1758) was studied in specimens collected at Maldonado Department (Uruguay), where monthly surveys were made between August 1998 and March 2000. A total of 143 frogs were collected, measured, sexed, and dissected, to assess stomach contents. The anurans were grouped into three age classes and four categories (considering sex and capture date). The trophic amplitude for each age class and sex-season category was quantified using Shannon-Weaver Index, and the trophic niche overlap between ages and categories by using the Pianka Index. Comparisons among treatments were made by G-tests. The most important prey items were coleopterans (IRI = 2547), and significant correlations were found between predator and prey sizes. The major differences on diet composition were found between extreme age classes (froglets and adults). Significant differences were also detected between sexes in the cold season but not in the warm season. Any of these changes in diet may be related with the availability of prey.
Feeding ecology of endemic frogs of the Atlantic Forest in southern Brazil
Anais da Academia Brasileira de Ciências, 2022
Our objective was to describe and compare the diet of endemic anurans of the Atlantic Forest, as well as to evaluate the influence of biotic factors on the trophic ecology of the species. We conducted the study in Mananciais da Serra (Piraquara-PR), a transition region between mixed and dense ombrophilous forest, between January 2019 and February 2020. In this work, we describe the diet of eight species: Aplastodiscus albosignatus, Boana semiguttata, Bokermannohyla circumdata, Ischnocnema henselii, Leptodactylus notoaktites, Proceratophrys boiei, Rhinella abei and Scythrophrys sawayae. Coleoptera were important prey in the diet of most species, except for B. circumdata and L. notoaktites. All species showed potential selection for some category of prey. We observed a correlation between the size of the individuals and the volume of consumed prey in I. henselii. In general, the niche overlap between species was low, and most species had a broad trophic niche.
2017
Trueb, 1994), and are preyed upon many vertebrates and invertebrates (Toledo et al., 2007). Usually, predation on anurans by invertebrates occurs mostly during larval and adult stages, but they also attack on anuran spawns (Downie et al., 1995; Santos, 2009). Among the invertebrates that may feed on anurans, there are records of beetles, waterbugs, ants, spiders and crabs (Duellman and Trueb, 1994; Toledo et al., 2005; Caldart et al., 2011). Predation events, involving anurans and invertebrates, may be trivial in nature, however these records are dependent of fortuitous observations (Pombal Jr, 2007; Santana et al., 2009). Although amphibians feed mainly on invertebrates, anurans are commonly documented as prey of invertebrates, this relationship is determined by the size of the individuals involved (e.g. Toledo et al. 2005; Santana et al., 2009; Caldart et al., 2011; Baracho et al., 2014). Therefore, the role frogs play in food webs may vary depending on their size (Gaiarsa et al.,...
Biota Neotropica
Anurans are predator and prey, playing an important role in ecosystem functioning. The diet composition is closely related to feeding strategy, and the information about prey items is useful to understand intra and interspecific interactions in trophic webs. Here we determined diet composition, feeding strategy, and relation between prey ingestion and body measures of Crossodactylus timbuhy, a recently described anuran species. We found 466 prey items from 20 prey categories in the stomach of 66 specimens (15 males and 51 females) of C. timbuhy. The diet consists mostly of Formicidae and Coleoptera, the items with the highest number, frequency of occurrence and prey importance. The diet composition was relatively similar to other species of Crossodactylus. Prey volume was positively related to frog size and weight, suggesting frogs may feed upon any prey they can swallow. Diet showed some variation between sexes. Despite females were larger and heavier than males, females had higher consumption of smaller prey, and ingested a larger number of prey categories. We suggest C. timbuhy has an invertebrate-opportunistic feeding habit. It is likely C. timbuhy uses a combination of 'sit-and-wait' and 'active search' strategies due to high consumption of both highly mobile and sedentary prey.