Do human-induced habitat changes affect the feeding behaviour of frogs? The case of Pseudis minuta Günther, 1858 (original) (raw)
Related papers
Individual-level diet variation in four species of Brazilian frogs
Journal of Animal Ecology, 2009
Many natural populations exploiting a wide range of resources are actually composed of relatively specialized individuals. 2. This interindividual variation is thought to be a consequence of the invasion of 'empty' niches in depauperate communities, generally in temperate regions. If individual niches are constrained by functional trade-offs, the expansion of the population niche is only achieved by an increase in interindividual variation, consistent with the 'niche variation hypothesis'. 3. According to this hypothesis, we should not expect interindividual variation in species belonging to highly diverse, packed communities. 4. In the present study, we measured the degree of interindividual diet variation in four species of frogs of the highly diverse Brazilian Cerrado, using both gut contents and δ 13 C stable isotopes. 5. We found evidence of significant diet variation in the four species, indicating that this phenomenon is not restricted to depauperate communities in temperate regions. 6. The lack of correlations between the frogs' morphology and diet indicate that trade-offs do not depend on the morphological characters measured here and are probably not biomechanical. The nature of the trade-offs remains unknown, but are likely to be cognitive or physiological. 7. Finally, we found a positive correlation between the population niche width and the degree of diet variation, but a null model showed that this correlation can be generated by individuals sampling randomly from a common set of resources. Therefore, albeit consistent with, our results cannot be taken as evidence in favour of the niche variation hypothesis.
Intrapopulation Diet Variation in Four Frogs (Leptodactylidae) of the Brazilian Savannah
Copeia, 2007
Age and sex-based as well as individual-level diet variation are known to occur in many natural populations, and may have important ecological and evolutionary implications. In the case of individual-level diet variation, most examples come from species-poor, temperate communities, and it is currently believed that it results from population niche expansion following interspecific competitive release. We investigated and measured the intrapopulation diet variation in four species of frogs, Leptodactylus (=Adenomera) sp., Eleutherodactylus cf. juipoca, L. fuscus, and Proceratophrys sp., that are part of species-rich frog communities of the Brazilian Cerrado. Specifically, we investigated age and sex-related, as well as individual-level, diet variation. We measured individual-level diet variation with the IS index of individual specialization, which is a measure of the degree of overlap between individual niches and the population niches. We found no ontogenetic shifts or sex-related differences in the types of prey consumed. However, we found evidence of individual-level diet variation in the four studied species (IS~0.2-0.5). There was a negative correlation between IS and the population niche width (r = -0.980; P < 0.0001), indicating that interindividual diet variation is more pronounced in more generalized populations. This pattern suggests that individual niche widths remain constrained even when population niche breadth is wide, consistent with the presence of functional trade-offs. We found no evidence that these trade-offs arise from morphology, since there was no diet-morphology correlation. We hypothesize that trade-offs have a behavioral or physiological basis, which needs further investigation. This is the first documented case of individual-level diet variation in a diverse tropical community, indicating that this phenomenon is not restricted to competitive release-driven niche expansion in temperate, depauperate communities.
Feeding ecology of endemic frogs of the Atlantic Forest in southern Brazil
Anais da Academia Brasileira de Ciências
Our objective was to describe and compare the diet of endemic anurans of the Atlantic Forest, as well as to evaluate the infl uence 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
Mechanisms underlying frog occupancy patterns in a landscape mosaic of tropical forest and pasture
2008
of a dissertation at the University of Miami. Dissertation supervised by Professor Julian Lee. No. of pages in text. (134) Habitat modification is the primary cause of amphibian population declines worldwide. Some species survive in modified habitats whereas others become restricted to small, isolated forest patches. Although many studies compare species richness and composition between modified and intact habitats, the factors and mechanisms that maintain biodiversity in these landscapes are poorly understood. I asked how life history traits and habitat features influence interspecific variation in frog occupancy patterns in tropical pasture and forest. To identify mechanisms underlying occupancy patterns, I used experiments to examine how abiotic conditions in different habitats influence the vital rates of tadpoles. I also explored whether tadpoles use a carnivorous foraging strategy to improve performance in nutrient-poor, ephemeral pools in pasture. Although modified and intact habitats offer abiotic environments that differ in quality for frogs, pastures contribute to the maintenance of biodiversity in fragmented landscapes. I detected an equal number of species but substantially different assemblage composition in forest and pasture. Species that occurred in pasture had different traits than those in forest, including larger body sizes, larger clutch sizes, larger geographic ranges, and reproductive modes that depend on water. The occurrence of pasture-specialists was associated with habitat features at small spatial scales, whereas the occurrence of forestspecialists was associated with habitat features at small and large spatial scales. An I am very grateful to my advisor, Julian Lee, for the wisdom he has bestowed upon me during all phases of my study, from its formation, to implementation, and completion. Ray Semlitsch offered valuable advice on experimental design and statistical analyses throughout my study. I thank Don DeAngelis for always having his door open when I had questions. Matt Potts encouraged me to think in terms of the bigger picture. I am grateful to each of my committee members for offering helpful comments and criticisms that improved early versions of each chapter. I was fortunate to receive funding from several sources. The Environmental Protection Agency awarded me a fellowship through the Greater Research Opportunities Program, which allowed me to spend over two years in the field. I thank Bert Kerstetter and the organization Friends of the Osa (formerly TUVA) for an Evergreen fellowship. The Avina Foundation supported my early work in a teak plantation in Panama. The Department of Biology at the University of Miami awarded me a grant from the Kushlan-Frohring Graduate Research Support Fund. Additionally I received several grants from the University of Miami Kriloff fund and one from the Graduate Activity and Funding Allocation Committee to present my work at meetings. I thank the Ministerio de Ambiente y Energía in Costa Rica for granting permits (INV-ACOSA-005-06) to conduct my work and the many employees who helped speed the process. I am also grateful to IACUC at the University of Miami (Protocol 04-076). I appreciate the help of Maria Villanueva, who gave advice on the GIS, and Douglas Heller, who offered assistance in preparing my defense presentation. Roy McDiarmid and Ross Alford offered their expert knowledge about the natural history and iv ecology of different species. David Matlaga, Bob Muscarella, Ron Heyer, and Nancy Karraker offered helpful comments on previous drafts. Participation in the Pan-American Advanced Studies Institute course on amphibian declines was instrumental in helping me to form relationships with other amphibian ecologists with similar goals. I especially appreciate the advice and friendships I have formed with Caren Goldberg, Elizabeth Harper, Nancy Karraker, and Cori Richards. I also appreciate the support of staff in the Department of Biology, especially Beth Goad, and of many fellow graduate students and friends including Nicole Cushion,
Feeding habits of the Robber Frog Pristimantis paulodutrai (Bokermann, 1975) in northeastern Brazil
Biota Neotropica, 2021
Studying feeding habits is crucial to understand complex predator-prey interactions. Even though anurans play a fundamental role in the control of arthropods populations, the diet of several Neotropical species is poorly known. We describe the frequency and occurrence of prey items and their dry mass in stomach contents of the Robber Frog Pristimantis paulodutrai in the north east of the state of Bahia, Brazil. Based on the stomach contents of 30 individuals, Araneae, Isopoda, and Formicidae were found to be the most important food items. The generalist diet of this frog, which seems to be phylogenetically conserved among Pristimantis, is likely to be linked to its ecological dominance in the habitats surveyed. Our study corroborates the high trophic relevance of Robber Frogs in tropical forests as generalist predators.
South American Journal of …, 2009
Based on the stomach content analysis of 113 individuals, the diet of the invasive amphibian Lithobates catesbeianus (american Bullfrog) was examined in four sites located within the municipality of viçosa (20°45's and 42°51'w), state of Minas gerais, Brazil, from august 2005 to March 2007. the effects of frog size and sexual maturity on stomach contents were determined. Prey items were grouped according to their primary habitat, being classified as aquatic, terrestrial and amphibious. in general, the most frequent prey categories were post-metamorphic anura, Diplopoda, hemiptera, hymenoptera formicidae and araneae. the diet of adults of both sexes was similar, but differed from the diet of young frogs. terrestrial prey were most abundant both in number and occurrence. for adult Bullfrogs, amphibious prey were most significant in volume. there was a significant correlation between prey and predator sizes, as well as a greater consumption of native anurans by larger Bullfrogs. the results confirmed that Bullfrogs have a generalist feeding habit that can have important negative effects on native amphibian communities in environments occupied by this invasive species.
Although the feeding ecology of sympatric anurans has been studied, less is known about the food habits of co-occurring invasive and native frog species, particularly in the Neotropics. We compared the food habits of invasive bullfrogs (Lithobates catesbeianus) and native thin-toed frogs (Leptodactylus cf. latrans) in a locality of Southeastern Brazil. Monthly field surveys and stomach content analyses were performed between September 2008–April 2009 and September–November 2009. Prey items were identified to the lowest taxonomic level and diet overlap was estimated. Juveniles of both species had similar body sizes, but adult thin-toed frogs were smaller than adult bullfrogs. Insects and spiders dominated the diets of juveniles of both species and of adult thin-toed frogs, whereas anurans and water bugs predominated in adult bullfrog diets. Thin-toed frogs consumed a larger number of prey items than bullfrogs, which in turn consumed more voluminous prey items. Aquatic and amphibious prey items were more common in bullfrog diets. Adult thin-toed frogs preyed on juvenile bullfrogs, although the opposite was not observed. Diet overlap of equivalent age groups varied from low to intermediate between species. Our results showed that that dietary differences may be one of the factors allowing the coexistence of both species at the studied area, although not excluding possible negative impacts on native thin-toed frogs because of the presence of invasive bullfrogs.
Diet of a threatened pond frog differs over a small spatial scale
Suitability of habitat patches affects demographic processes and consequently influences the viability of populations. In order for managers to consider the potential of resources on a scale appropriate to their use, it is important to understand the processes that influence the ecology of threatened species. Differential growth rates of Litoria aurea (green and golden bell frog) at Sydney Olympic Park, Australia, may be explained by prey availability and diet. We tested: (1) whether food availability differed among precincts at Sydney Olympic Park and (2) whether the diet of L. aurea was influenced by availability of invertebrate prey. Diets were distinct among precincts and reflected the variation in biomass and richness of invertebrate assemblages. Precincts with greater biomass corresponded to areas with faster individual growth rates and greater habitat structure. The differences in diet and individual growth rates of L. aurea among precincts at Sydney Olympic Park demonstrate how caution must be applied to generalising population function, even within a small area.
Food niche overlap between two sympatric leaf-litter frog species from Central Amazonia.pdf
We studied the feeding habits and similarities in the diet of two sympatric and syntopic Amazonian frog species, Anomaloglossus stepheni (Aromobatidae) and Leptodactylus andreae (Leptodactylidae) in a forested area in Central Amazonia. The breadth of the trophic niche of these species was 5.89 and 3.75, respectively, and approximately 85% of their diets were similar. Ants were main food item in the diets of both frog species. The coexistence between these frog species may be facilitated by the significant differences in the size of their mouths. This difference allows them to consume preys items of different sizes.