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Predators influence microhabitat selection and activity level of tadpoles, but it is still unclear how such responses to predators differ among species and how water column's depth influences this predator–prey interaction. Here, we experimentally tested whether the presence of Odonata water nymphs influenced the spatial use and activity of benthic and nektonic tadpoles in different food availability contexts. Benthic tadpoles occupied and consumed more food at the bottom level, irrespective of predator's presence. However, when predators were at the bottom, benthic tadpoles remained close to the cages, suggesting a typical “stay-still” defensive behavior known for Physalaemus nattereri (Steindachner, 1863). Nektonic tadpoles occupied shallower depths on predator presence, and they also consumed less food and avoided the predator by selecting food sources far from it. When the predator was at the bottom level and food was available, the distance of tadpoles to the cage tended to be smaller. Scinax fuscovarius (Lutz, 1925) tadpoles were more active when food was absent regardless of predator's presence. When food was available, these tadpoles generally occupied and consumed more food at the bottom level. Tadpole responses depended not only on predator presence but also on a complex net of factors, which included tadpole habit, antipredatory behavior, and availability and location of food.

Made available in DSpace on 2022-04-29T08:35:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-11-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) One of the many taxonomic challenges found in the Dendropsophus microcephalus species group is the Dendropsophus walfordi distinction from D. nanus. Recent phylogenetic inferences have indicated the paraphyly of these species, although they were not designed to assess this issue. To contribute to the delimitation of these species, we analyzed the 12S, 16S and COI mitochondrial genes, the morphological traits, and the advertisement calls of specimens from northern Amazonia to Argentina, including the type localities of D. nanus and D. walfordi. Paraphyly of D. nanus with respect to D. walfordi was inferred by maximum-parsimony and Bayesian analyses, and five major clades exhibiting nonoverlapping geographic distributions were recognized. The bPTP and ABGD analyses supported the existence of five independently evolving lineages in this complex. Acoustic and morphological data clearly distinguished the clade that included the topotypes of D. walfordi from the others, corroborating the validity of this species. To avoid the paraphyly of D. nanus with respect to D. walfordi, we recognize the clade distributed from central-southern Brazil to Argentina as D. nanus, the clade distributed in Amazonia as D. walfordi, and discuss the existence of unnamed cryptic species closely related to D. nanus and D. walfordi. Departamento de Biologia Estrutural e Funcional Instituto de Biologia Universidade Estadual de Campinas (UNICAMP) Laboratório de Taxonomia Sistemática e Ecologia Comportamental de Anuros Neotropicais Faculdade de Ciências Integradas do Pontal Universidade Federal de Uberlândia (UFU), Rua 20 no 1.600, Bairro Tupã Departamento de Ciências Biológicas Instituto de Biociências Letras e Ciências Exatas Universidade Estadual Paulista (UNESP) São Paulo Coordenadoria de Pesquisas em Ecologia Instituto Nacional de Pesquisas da Amazônia (INPA) Departamento de Biologia Centro de Ciências Biológicas e da Saúde Universidade Federal do Maranhão (UFMA), Campus do Bacanga Departamento de Ciências Biológicas Instituto de Biociências Letras e Ciências Exatas Universidade Estadual Paulista (UNESP) São Paulo CAPES: 001 CAPES: 1143326 FAPESP: 2010/12600-4 CNPq: 300903/2015-4 CNPq: 302328/2017-3 CNPq: 305169/2019-0 CNPq: 446935/2014-0

Made available in DSpace on 2020-12-12T02:29:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) For grazing animals that share spatial and alimentary resources, the relationship between differences in oral morphology and the physical properties of substrates can help explain how and where species forage. The substrates may require different efforts from animals to access and remove food from their surfaces. Variation in oral morphology may produce differences in animals’ feeding efficiency. We tested whether one substrate characteristic, the surface texture (i.e., smooth, striated and rough), influences the growth and food consumption rates of anuran larvae from nine species with different oral morphologies. Tadpoles with few keratinized oral structures and those with more gaps in the marginal papillae row were more efficient grazing on smooth and rough surfaces, respectively. This may indicate possible feeding specializations. Conversely, tadpoles with a high number of labial tooth rows, regardless of the number of gaps in these structures, and those with only a dorsal gap in the marginal papillae row were equally efficient feeding upon all substrate textures. Tadpoles with the generalized labial tooth row formula 2(2)/3(1), had higher growth rates than the other species, suggesting an adaptive significance for this common oral morphology. We demonstrated that species differ in feeding efficiency when grazing on substrates with different textures. This can help elucidate the adaptive significance of variation in tadpole oral morphology. We also provide insights on resource selection and niche partitioning among species, especially for those whose diets do not differ in quantity or quality, as it is common in anuran larval assemblages. Departamento de Ecologia UFG-Universidade Federal de Goiás Departamento de Zoologia E Botânica UNESP-Universidade Estadual Paulista “Júlio de Mesquita Filho” Department of Biology Allegheny College Department of Cellular and Physiological Sciences University of British Columbia Departamento de Zoologia E Botânica UNESP-Universidade Estadual Paulista “Júlio de Mesquita Filho” CAPES: 1562647 FAPESP: 2010/52321-7 CNPq: 302328/2017-3 CNPq: 420051/2016-3 CNPq: 563075/2010-4

In nature, tadpoles encounter food on substrates oriented at different angles (e.g. vertically along stems, horizontally on the bottom of the pond). We manipulated the orientation of food-covered surfaces to test how different orientations of surfaces affect tadpoles' feeding efficiency. We studied taxa that differed in the oral morphology of their larvae and position in the water column. We hypothesized that species would differ in their ability to graze upon surfaces at different orientations and that differences in the tadpoles' feeding ability would result in different growth rates. The orientation of food-covered surfaces did not affect the growth rate of bottom-dwelling tadpoles (whose growth rate varied only between species). Among midwater tadpoles, some species appear to have a generalist strategy and experienced a high relative growth rate on numerous substrate orientations, whereas others achieved high growth rates only on flat substrates (i.e. at 0° and 180°). We conclude that oral morphology constrains tadpoles' ability to feed at different substrate orientations, and this could lead to niche partitioning in structurally complex aquatic environments. Because physical parameters of the environment can affect tadpoles' growth rate, characterizing these features might help us better understand how competition structures tadpole assemblages., Summary: We provide new insights on species' niche partitioning as we show that the orientation of substrates can affect the growth rates of tadpoles with different oral morphologies.