ArticlePDF Available

Abstract

This study looks at resource (trophic, spatial and temporal) use and foraging tactics in a community of eight species of anuran amphibians at a seasonal locality in south India. Within the community, the species are differentiated into a sit-and-wait group, which are large, cryptic and sedentary foragers showing a relatively wide dietary spectrum; and a widely foraging group, whose members are aposematically coloured, and actively forage on a few prey types. However, there are indications that these modes represent ■ two ends of a continuum, with some species showing greater plasticity in prey use than others. Sympatric species, except dietary specialists, were found to generally overlap broadly in diet. Microhabitats are partitioned to a greater degree than food, the most closely related species, which tend to show similar diets, selecting different foraging areas. Seasonality affects the activity of two of the three non-sit-and-wait species, but none of the sit-and-wait ones, possibly because sedentary foraging is more energetically effi­ cient during the resource lean season. Net gains per unit energy spent are presumably lower than for active foraging. In general, both trophic and spatial niches increase in breadth with body size across species, with larger species taking more types of food and using more different microhabitat types than smaller ones. Smaller species take smaller prey, but the mean number of prey harvested is higher than in larger frogs. Differences in the use of envi­ ronmental resources are thought to be a factor in determining species composition in a community, within which larger species tend to be generalists, while their smaller sympatrics are more specialized in their use of environmental resources.
... Amphibians form a vital link in the food chain as they are subsequently preyed upon by other vertebrates and studying the diet of adult amphibians has gained particular importance in the backdrop of global population declines of both amphibians (Wake and Koo 2018) as well as insects (Wagner 2020). Information on the diet of anurans has enabled us to gain insights into ecology and natural-history (Donnelly 1991;Donnelly and Guyer 1994;Measey et al. 2015;Le et al. 2020), geographic distributions (Williams et al. 2006, detect fluctuations in populations (Bonansea and Vaira 2007), resource use and partitioning (Toft 1981(Toft , 1985Donnelly 1991;Das 1996a), community structure (Toft 1980(Toft , 1981(Toft , 1995aLima 1998;Lima and Magnusson 1998;de Paula Lima et al. 2010), evolution of survival strategies among the predator and the prey (Toft 1995b;Cladwell 1996;Darst et al. 2005) and, help design conservation interventions such as captive husbandry (Griffiths and Pavajeau 2008). ...
... Studies on the diet of anurans in India have been scattered and include anecdotal observations (e.g. Chibber 1911;Agharkar 1912;Isaac and Rege 1975) and systematic studies on particular species as well as the community (Rangaswamy and Channabasavanna 1973;Mohanty-Hejmadi and Acharya 1982;Das 1996aDas , 1996bChowdhary et al. 2016;Mohanty and Measey 2018). Yet, there is neither systematic documentation nor comprehensive assessments on the persistence of anurans in humanmodified agricultural landscapes in India (Aravind and Gururaja 2011). ...
... where PO t is the percentage of occurrence (100 X number of samples containing t item/ total number of samples), PI t is the percentage of individuals (100 X total number of individuals of t in all samples/total number of individuals of all taxa in all samples), and PVt is the percentage of volume (100 X total volume of individuals of t in all samples/total volume of all taxa in all samples). Trophic niche breadth was calculated using the Shannon-Weaver Index following Das (1996a): ...
Article
Rice-paddy agriculture is widely expanding, particularly in Asia. Rice-paddy fields are stagnated with water and insecticides are applied to control pests. Expansion of agriculture and pesticide are known drivers of declining amphibian populations globally. Yet, several amphibians persist in such temporary wetlands. How amphibians persist in this landscape matrix is not clearly understood. We document amphibian diversity in rice-paddy fields in south India and examine trophic interactions of the two most abundant species. From 60 rice paddy fields, we recorded six species of anurans among which, Minervarya caperata and Microhyla ornata were most abundant. The stomach contents of 57 individuals of the two species were extracted. They consumed prey items belonging to eight orders and 56 taxonomically distinct units dominated by Diptera and Hymenoptera: Formicidae. Although individuals of M. ornata were smaller in body size compared to M. caperata, both species consumed a similar number of arthropods. The dietary niche breadth of M. caperata was wider than M. ornata and the diets of the two species did not overlap greatly. We discuss our findings in the context of prey availability, foraging strategies, and highlight the role of anurans in pest control.
... While the above-mentioned studies and numerous others have examined food niche partitioning between a variety of vertebrates Rugiero 1991, 1998;Kronfeld-Schor and Dayan 1999;Zapata et al. 2005), relatively few studies have examined niche partitioning in amphibian communities, more specifically among anurans (Toft 1985;Das 1996;Vignoli and Luiselli 2012). Hence, our understanding of interspecific interactions between sympatric anurans in relation to their feeding and diet is at its infancy. ...
... Similar studies on the diet of amphibian communities in South America, North America, Europe, Oceania, and Asia also identify ants, beetles, insect larvae and dipterans as important prey categories (Jordão-Nogueira et al. 2006;Wachlevski 2008). Furthermore, hymenoptera appears to be the most frequently used food resource in this amphibian community, which has also been observed in similar studies in several different regions of the world (Toft 1980(Toft , 1985Donnelly 1991;Das 1996;Cogălniceanu et al. 2001;Darst et al. 2004). Although all six species of amphibians consumed hymenopterans in this study, predominantly aquatic and terrestrial species differed in the hymenopteran species consumed. ...
... This may be due to their active foraging strategy. Studies on amphibian foraging in other parts of the world such as Africa, South America and the Indian subcontinent indicate that amphibians with a sit-and -wait foraging strategy have a narrow niche breadth in comparison to active foragers, which feed on a wide range of prey items (Das 1996;Ferreira and Teixeira 2009;Hirschfeld and Rödel 2011;Caldart et al. 2012;Rebouças and Solé 2015). Although no direct observations have been made on the foraging strategy of U. rohani, the lowstandardised niche breadth value indicates that U. rohani could be a sit-and-wait forager. ...
Article
Full-text available
Understanding the conditions under which interacting species can persist is a major goal in ecology. Dietary partitioning is one of the major strategies that enables ecologically similar species to coexist in communities. In this study, we examined the dietary patterns of a selected group of amphibians in an amphibian community in northern Sri Lanka to understand differential resource use by coexisting species. The stomach flushing method was used to examine the diet of amphibians to study the niche breadth and pairwise species dietary niche overlap. Seventeen different prey categories were identified from the diet of six species of amphibians in the community. The most frequently used prey category by all amphibians was hymenoptera. Among the amphibians, some consumed several different prey categories (8–9 prey categories), while some were more specialised (e.g. Uperodon rohani fed only on ants), consuming only one or two different prey categories. The average niche overlap among the species in the community was 0.392 indicating low trophic niche overlap. This study indicates a low level of dietary niche overlap between the selected amphibian species and hence, a high degree of dietary niche partitioning. The findings also provide valuable insights into the dietary ecology of these amphibians, which will be invaluable for the formulation of conservation strategies.
... We found a generally low interspecific dietary niche overlap and narrow trophic niche breadth between and among L. magnus, P. grandocula, M. stejnegeri, O. laevis, A. muelleri, S. mearnsi, and S. natator from both low-and mid-elevation sites. The low dietary niche overlaps and narrow niche breadth could be attributed to the overlaps of microhabitat preferences (Delima et al. 2007, Ates & Delima 2008, Nuñeza et al. 2010, Plaza & Sanguila 2015, Coritico et al. 2018) and a species selection of specific prey items (Toft 1985, Das 1996, Hirai & Matsui 2000a, 2000b, Vignoli & Luiselli 2012) that may minimise competition for food resources (Toft 1985, Lima & Magnusson 1998, Cloyed & Eason 2017. At mid-elevation site, high dietary niche overlaps were observed between A. muelleri, L. magnus, and P. grandocula when Formicidae (ants) form a high proportion of these species' diet during sampling months of April, June, and July. ...
Article
We investigated trophic resource partitioning in seven syntopic anurans from low-and mid-elevation stream habitats of a tropical riparian ecosystem by utilising stomach content analysis (SCA) and stable isotope analysis (SIA). Our SCA data revealed dietary similarities, narrow trophic niche breadth, and low dietary niche overlap in Ansonia muelleri, Limnonectes magnus, Occidozyga laevis, Megophrys stejnegeri, Pulchrana grandocula, Sanguirana mearnsi, and Staurois natator which could be attributed to these anurans' selection of available local prey items. We confirmed ant-specialisation (myrmecophagy) of the Mindanao island endemic bufonid A. muelleri based on our temporal SCA dietary data. Our SIA estimates of assimilation of potential prey sources confirmed that L. magnus, P. grandocula, and O. laevis are generalist predators, opportunistically feeding on locally abundant insect prey items. This study on trophic resource partitioning in syntopic anurans provides the first picture of trophic interactions, i.e., predation and competition in stream communities in tropical riparian zones of a watershed ecosystem in northeast Mindanao of the southern Philippines.
... Chiasmocleis alagoanus had a specialized diet of Formicidae and Isoptera, reflecting a strong conservation in the diet Table 1. niche of the Microhylidae (Das, 1996;Parmelee, 1999;Solé et al., 2002;Wells, 2007). Despite a generalist feeding behavior, P. ramagii also showed a diet similar to that of closely related species, indicating a strong relationship with this major microhabitat and the kinds of prey found in leaf litter (Dietl et al., 2009). ...
Article
Full-text available
Many factors influence community structure, including stochastic, historical, or ecological factors. We test how phylogenetic relationships and morphology influence patterns of diet and microhabitat niche partitioning of an anuran community in the Atlantic forest in northeastern Brazil. We conducted fieldwork in an urban fragment of the Atlantic forest. Niche breadth for microhabitat use was low for all species pairs, whereas diet niche breadth was high for most. The main prey categories were Coleoptera and Orthoptera, and closely related species showed a distinct diet. We also found a non-random pattern of resource use for diet and microhabitats. Phylogenetic relationships influenced microhabitat, but not diet, use of hylids and leptodactylids. Morphological variability was not clustered in only one node, nor in a few nodes, and trait values were not skewed to the root or the tips of the phylogeny and appear to concur with phylogenetic relationships for microhabitat use. Therefore, phylogenetic relationships influenced microhabitat use, whereas ecological processes determined diet. Muitos fatores influenciam a estrutura de uma comunidade, sejam de ordem estocástica, histórica ou ecológica. Nós testamos como as relações filogenéticas e a morfologia influenciam os padrões na partição de nicho da dieta e uso de microhabitat em uma comunidade de anuros de Mata Altântica do nordeste do Brasil. Nós conduzimos o estudo em um fragmento urbano de floresta atlântica no nordeste brasileiro. A largura de nicho de uso de microhábitat foi baixa para todos os pares de espécies, enquanto a de dieta foi alta para a maioria. As principais categorias alimentares foram Coleoptera e Orthoptera, sendo que espécies mais próximas filogeneticamente apresentaram dieta distinta. Nós também encontramos um padrão não aleatório no uso dos recursos de dieta e uso de microhábitat. O grau de parentesco influenciou o uso de microhábitat em hilídeos e leptodactilídeos, mas não a dieta. A variabilidade morfológica não foi agrupada em um nó, nem em poucos nós, e os valores dos atributos não estão enviesados em direção a raiz ou aos ramos terminais da filogenia, e, aparentemente, corrobora as relações filogenéticas para uso de microhábitat. Portanto, o parentesco filogenético influenciou o uso de microhábitat, enquanto a dieta foi mais influenciada por processos ecológicos.
... Such structures allow coexistence of species within similar niches via resource partitioning (Schoener, 1974;Pianka, 1974). Studies of resource partitioning and niche organization within tropical amphibian are numerous, especially those dealing with microhabitat and diet utilization of either adults (Inger & Colwell, 1977;Inger et al., 1987;Das, 1996;Vignoli and Luiselli, 2012) or larval stage of frog species (Heyer, 1976;Morin, 1983;Inger et al., 1986;Strauß et al., 2013). Amphibian assemblages tend to form ecological guilds in forested area, as compared to non-forested area (Inger & Colwell, 1977), reiterating the importance of species-area relationship in community structure. ...
Thesis
Full-text available
Amphibians are particularly sensitive to environmental change, and many studies have demonstrated the effect of anthropogenic disturbance on populations. Several ecological traits within amphibians are vulnerable to landscape change, including reproductive strategies. Borneo is one of the richest tropical regions for amphibians, yet remains poorly understood in many aspects of their diversity and ecology. Rapid deforestation occurring on Borneo poses major threats to amphibians via habitat degradation and isolation. Anuran amphibians (frogs) are grouped within different guilds, defined as groups whose members exploit similar breeding sites. This study investigates how guilds of frogs respond to different degrees of disturbance, using proportionate canopy cover as a surrogate for disturbance and reproductive modes for guilds, within a lowland dipterocarp forest in central Sarawak. Additionally, variation in body and clutch size within different amphibian guilds was also investigated. Visual and Acoustic Encounter Surveys along transects were conducted at four sites between May 2014 to April 2015. A total of 46 species, associated with 12 reproductive modes, were recorded, in addition to two unassigned to a specific mode. Species diversity indices were the highest at forest patches with low disturbance levels, while Moristia-Horn index calculated for species composition in all four sites showed dissimilarity among sites. Mode 2 (egg and tadpole in stream) was shown by the greatest number of species (36.1%), while the least (2.1%) shown by five different modes, Modes 8 (phytotelm), 11 (foam nest on pond), 20 (parental care), 23 (direct developers) and 25 (arboreal eggs, tadpoles in stream), each represented by a single species. Sites with low species richness show fewer reproductive modes. Four type of breeding habitat were recognized: Stream, pool, phytotelm and terrestrial, in which six type of frog guilds were found utilizing these habitats. Results for body and clutch sizes of frogs utilizing each habitat show significant differences. Terrestrial breeding frogs is smaller than aquatic breeding frogs, while clutch size is larger in stream breeders compared to terrestrial breeders. Differences in body and clutch size reflect adaptations of amphibian to particular habitats. Canopy cover shows no correlation with either species richness or reproductive mode. These findings suggest frog species richness and guilds are distributed according to habitat preferences of individual species. Anthropogenic disturbances may generate additional breeding sites, which may be utilized by human-commensal species. Some environmentally sensitive modes, such as phytotelm breeding, occur only in forested habitats. These results suggest that amphibian conservation plans should attempt at maintaining habitat heterogeneity in order to preserve both species and representative ecological traits. The diversity in reproductive mode especially in different species of frog permits coexistence within the same habitat and reduce competition during development of their larva. Habitat alteration limits the number of occurring microhabitat, therefore can increase the competition on resources and space.
... • Estrategia de forrajeo (F): se define como la estrategia comportamental utilizada por una especie para capturar alimento, la cual tiene gran influencia sobre la dieta (Duellman y Trueb 1994, Das 1996, Parmelee 1999). Diferentes grupos de ranas tienen distintas estrategias de consumo de presas. ...
... • Estrategia de forrajeo (F): se define como la estrategia comportamental utilizada por una especie para capturar alimento, la cual tiene gran influencia sobre la dieta (Duellman y Trueb 1994, Das 1996, Parmelee 1999). Diferentes grupos de ranas tienen distintas estrategias de consumo de presas. ...
... • Estrategia de forrajeo (F): se define como la estrategia comportamental utilizada por una especie para capturar alimento, la cual tiene gran influencia sobre la dieta (Duellman y Trueb 1994, Das 1996, Parmelee 1999). Diferentes grupos de ranas tienen distintas estrategias de consumo de presas. ...
Chapter
La ecología funcional provee una información clave para la evaluación del estado de vulnerabilidad o resiliencia de los sistemas biológicos y los servicios ecosistémicos asociados a estos. Esta consideración es importante frente a los retos actuales de manejo integral del territorio que involucran la declaración de áreas protegidas, la restauración de procesos ecológicos y el manejo de especies invasoras, entre otros. La consideración de la diversidad de rasgos funcionales que sustentan, directa o indirectamente, diferentes servicios ecosistémicos y las características espaciales de la distribución potencial de los mismos, permiten el mapeo de procesos que pueden apoyar la oferta de servicios específicos. Su conocimiento e investigación es fundamental sobre todo en los países cuya diversidad biológica es un pilar para el desarrollo socioeconómico y el bienestar humano. El reto actual consiste en aumentar la información generada a partir de rasgos funcionales que sea puesta a disposición de la comunidad científica, también traducida e integrada en recomendaciones que disminuyan la pérdida de la función ecosistémica en el territorio.
Article
Full-text available
The Indian cricket frog that is widespread across the plains of peninsular India has thus far been represented as Fejervarya limnocharis (Gravenhorst, 1829), a name that has been applied to a multitude of different populations in tropical Asia. An array of taxonomic studies resulted in description and recognition of many species and consequently F. limnocharis has been restricted to Java. Our nomenclatural analysis revealed a nomen Rana agricola Jerdon, 1853, so far treated as incertae sedis; this very senior nomen is the only available nomen erected based on material(s) originating from southern Indian plains. We herein designate a neotype for this species and formally apply this nomen to this population, in the combination Fejervarya agricola (Jerdon, 1853) and add some morphological and natural history notes on this species.
Article
Full-text available
Based on a recent molecular phylogenetic study, the South Asian microhylid genus Uperodon (subfamily Microhylinae) currently comprises of 12 valid species that are largely restricted to India and Sri Lanka. Considering the revised generic-level status of its various members, here we review the taxonomy of all known species in this genus and clarify their nomenclatural status and geographical distribution, by integrating evidence from genetics, adult and tadpole morphology, breeding ecology, and bioacoustics. Our molecular analyses of a mitochondrial 16S rRNA gene fragment combined with external and internal morphological studies also revealed a distinct new species in the genus. This species, formally described as Uperodon rohani sp. nov., is endemic to Sri Lanka and widely distributed at lower elevations in the island. For nomenclatural stability of various previously known members, the following actions are also undertaken: (1) redescription of the poorly-defined species Ramanella anamalaiensis Rao (= Uperodon anamalaiensis) and Hylaedactylus montanus Jerdon (= Uperodon montanus); (2) neotype designation for Ramanella anamalaiensis Rao (= Uperodon anamalaiensis), Ramanella minor Rao, Ramanella mormorata Rao (= Uperodon mormorata), and Ramanella triangularis rufeventris Rao; (3) lectotype designation for Callula variegata Stoliczka (= Uperodon variegatus); and (4) synonymization of Ramanella minor Rao with Uperodon anamalaiensis.
Book
This book addresses the question of what determines species richness in tropical animals by comparing and contrasting the communities of the five major classes of vertebrates in two environments considered to be the most species-rich on Planet Earth - the coral reef and the rainforest. All the contributors were asked to examine how so many species could coexist in such communities and to discuss the ways species assemblages might have evolved over time. Because the coauthors are ecologists, emphasis is quite naturally placed on the first of these two questions, and the factors contributing to the maintenance of a-diversity are discussed at length. However, the question of the very origin of species richness can never be eluded, though it is more an evolutionary problem than an ecological one; it has therefore also been given some attention occasionally. Since we believe that long-term descriptive data and extended field experience are absolutely essential to formulate meaningful questions and pro­ pose realistic models, contributors were selected on the basis of their prolonged field practice; all of them actually spent years in the field and/or participated in long-term research programs. The present volume has its origin in a symposium held on August 15, 1986 at Syra­ cuse, New York, during the Fourth International Congress of Ecology.
Chapter
Tropical rainforests or "jungles" are commonly thought of as harboring a vast array of man-eating crocodiles, gaudy lizards, noisy frogs, and huge snakes which either "crush" their victims or dispense with them quickly by injection of lethal venoms. This view of the rainforests, so commonly portrayed in Hollywood productions, contains less truth than it does fiction. In contrast, the scientific literature dealing with herpetofaunal communities of tropical rainforests is rieh in factual information, the interpretation of which frequently is more fictional than true.