Biology subjects

Provete, D. B.

Publications and source records attributed to Provete, D. B..

11 recordsLinked to original sources

bioRxiv2026

Seasonal hepatic plasticity follows a temporal response hierarchy in a Neotropical frog

BackgroundSeasonal climate variation drives physiological change across levels of biological organization in ectotherms, yet whether these responses follow a predictable temporal hierarchy remains untested in wild populations. In a year-round field study of the Lesser Treefrog (Dendropsophus minutus, Anura: Hylidae) in Sao Jose do Rio Preto, southeastern Brazil, we sampled 40 to 68 adult males across a full annual cycle to quantify seasonal variation in four hepatic phenotypic modules spanning multiple organizational levels: liver histochemistry (pigments and glycogen; intracellular), cell and nucleus morphometry (cellular), tissue volumetric composition of hepatocytes, sinusoids, melanomacrophage centres and portal structures (tissue), and whole-body somatic indices of liver mass and body condition (organismal). We asked whether lower organizational levels respond faster to seasonal climate, as predicted by the bottom-up cascade framework originally proposed for toxicant exposure, or whether alternative hierarchies emerge when climate acts first through whole-organism physiology. To test whether climatic change precedes each biological response, we extended Procrustean superimposition to incorporate time lags, tested both forward and reverse directions, and complemented it with phenotypic trajectory analysis, phase analysis of monthly change, and lagged regression against temperature, precipitation, humidity and drought. ResultsSomatic indices and tissue composition tracked climate with no detectable delay, whereas histochemistry and cell morphometry accumulated a three-month delay, and tissue composition in turn led somatic indices by one month. Trajectory analysis separated the modules into a fast-responding group (somatic indices, histochemistry and morphometry) and a slower tissue-composition tier, a two-tier structure confirmed by paired bootstrap resampling in which the slow tier differed from every fast module in both displacement rate and total path length. The four modules were largely independent through time, and the two strongest concordances linked climate to tissue composition and to somatic indices. ConclusionsThese results reveal a temporal response hierarchy in which seasonal climate acts first on whole-organism energy balance and then propagates to tissue architecture and intracellular processes with module-specific delays, showing that the direction of the hierarchy depends on the nature of the environmental driver. We also introduce a general analytical framework for testing temporal precedence in short multivariate biological time series.

zoology↗

bioRxiv2026

Predator stimulus and habitat structure jointly shape antipredator behavior in frog species

When encountering a predator, prey must choose between immobility and flight, a decision shaped by predator proximity, habitat structure, body size, and evolutionary history. Despite extensive work on optimal escape theory, few studies have jointly modelled both the decision to flee and the intensity of flight in a phylogenetic comparative framework. Here, we used a Bayesian phylogenetic hurdle log-normal model to analyze the probability of immobility and the conditional jump distance in 534 trials from 89 males across 17 Neotropical frog species (seven families), exposed to a simulated snake predator in three arenas of varying structural complexity. Physical contact with the predator (touch) was the strongest predictor, reducing immobility probability from 94% to 15% and increasing jump distance by 26%. Habitat complexity increased immobility (bush > leaf litter > empty), and frogs in open arenas jumped 31% farther. Larger-bodied species were substantially more likely to remain immobile but did not jump farther, indicating that body size determines strategy choice rather than locomotor magnitude. Phylogenetic signal was strong for both components (Pagels {lambda} = 0.80 for jump distance; {lambda} = 0.71 for immobility), with phylogeny accounting for 69-75% of variance. Species random effects formed a phylomorphospace in which fossorial species showed highest immobility and arboreal/torrent species favored active escape. Substantial individual-level variation in immobility tendency (25% of variance) provides a heritable substrate for ongoing selection. Frog antipredator strategies are jointly shaped by ecological context and evolutionary history; hurdle models offer a powerful framework for decomposing behavioral decisions. LAY SUMMARYWhen a predator approaches, prey must choose between staying still or fleeing -- a decision depending on body size, habitat, and shared evolutionary history. We exposed 17 frog species to a snake in arenas of varying vegetation cover. Frogs fled when touched but mostly stayed still when only approached; larger species and those in dense vegetation were most likely to remain immobile. These antipredator strategies were strongly shaped by frogs shared ancestry.

animal behavior and cognition↗

bioRxiv2024

The effect of urbanization and local environmental heterogeneity on phenotypic variability in a tropical frog

1. Urbanisation reduces species richness and change community composition. However, little is known on how the phenotype of organisms with low dispersal ability respond to environmental changes associated with urbanisation in fast urbanizing centres, such as those in the Global South. 2. Here, we tested how urbanisation rate, local environmental heterogeneity, land surface temperature, and spatial gradients affect phenotypic traits associated with dispersal, resource acquisition, and performance, namely: body size, head shape, and leg length of the Dwarf Treefrog (Dendropsophus nanus) using a space-for-time substitution approach. 3. We took linear measurements from 768 individuals in 21 ponds along an urban gradient in central Brazil. We also measured local environmental variables and summarized them using Hill-Smith Principal Component Analysis. The spatial arrangement of ponds at multiple scales was described using Moran Eigenvector Maps. Those variables were then entered into a Structural Equation Model to test their direct and indirect effects on the mean and coefficient of variation (CV) of phenotypic traits. Additionally, we calculated the Scaled Mass Index as a proxy for fitness and estimated the adaptive landscape for body size, size-free leg length, and head shape. We also tested for spatial autocorrelation in traits. 4. Body size decreased from the periphery to the urban centre, whereas CV of body size and head shape had the opposite pattern. Body size increased, whereas CV of body size and head shape decreased in man-made ponds. The CV of leg length decreased with increasing land surface temperature. The remaining traits were not affected by any predictor variable. None of the traits were spatially autocorrelated. Both body size and head shape were under weak directional selection, but in opposite directions. 5. Our results suggest that the lack of a clear spatial variation in phenotypic traits can be due to a weak selection, due to a recent, although intense, urbanisation process. In conclusion, eco-evolutionary dynamics in tropical cities seem to have a different pace compared to temperate ones. Our results can contribute to building urban ecological theory that explicitly includes city age, their development, growth rate, and history.

ecology↗

bioRxiv2023

Biodiversity responses to forest cover loss: taxonomy and metrics matter

The actions required for biodiversity conservation depend on species responses to habitat loss, which may be either neutral, linear, or non-linear. Here, we tested how taxonomic, functional, and phylogenetic diversity of aquatic insects, dragonflies, frogs, and terrestrial mammals, as well as their species composition respond to forest cover loss. We hypothesized that taxonomic, functional, and phylogenetic diversity would respond nonlinearly (thresholds) to forest cover loss. Our findings do not support the current idea that a single threshold value of forest cover loss is applicable across tropical regions, or that some biodiversity facets are consistently more sensitive than others across different taxa. Species compositional responses to forest cover loss showed general patterns with thresholds between 30-50%. These results highlight the importance to consider multiple biodiversity facets when assessing the effects of forest cover loss on biological communities.

ecology↗

bioRxiv2022

Non-equilibrium processes prevail in shaping species richness and functional diversity of terrestrial vertebrates in a global hotspot

AimThe effects of equilibrium and nonequilibrium processes are generally investigated using species richness on a single biological group. However, little is known about how these two classes of processes also affect trait diversity, considering multiple taxa within the same geographical template. Here, we evaluated which variables representing equilibrium (topography, climate, and primary productivity) and nonequilibrium (diversification rate and evolutionary time) processes best explain species richness and trait diversity of four clades of vertebrates within the same global hotspot. We also investigated how trait disparity has accumulated over time and whether there are congruent spatial patterns between groups. LocationAtlantic Rainforest Time periodContemporary. Major taxa studiedTerrestrial vertebrates. MethodsWe tested whether the spatial pattern of Functional Dispersion (FDis), richness, diversification rate, and evolutionary time of each group are correlated. We used a spatially explicit structural equation model to test how species richness and functional dispersion are influenced by variables representing equilibrium and nonequilibrium mechanisms. Additionally, we explored how trait disparity accumulated over time in the four groups. ResultsWe found that non-equilibrium proxies, evolutionary time and diversification rate, played a primary role in driving species richness and trait diversity, with elevation and climate variables having only an indirect effect species and trait diversity via diversification rate and evolutionary time. We found a congruent pattern of species richness among all groups, except among ectotherms. In contrast, the spatial distribution of evolutionary time was distinct for each group. Main conclusionsDespite nonequilibrium processes were more important for generating large-scale diversity patterns within the same geographical template, the interplay between evolutionary time and dispersal ability have disparately determined the assembly of communities.

ecology↗

bioRxiv2020

High species turnover shapes anuran community composition in ponds along an urban-rural gradient

The rapid expansion of urban areas in which natural and semi-natural areas are replaced by human infrastructure, such as buildings and streets, is a major threat to biodiversity worldwide. However, little is known about how the structure of biotic communities is affected by urbanization in the tropics. Here, we tested the effect of land use types in urban and peri-urban areas on frog species richness and community composition in central Brazil. We selected 20 ponds differing in size and surrounding levels of urbanization as well as natural forest cover. We then used a Poisson GLM and a distance-based Redundancy Analysis (db-RDA) to relate species richness and community composition, respectively, to environmental variables. Variation in species richness was best explained by pond size (positive effect) and amount of urbanization (negative effect) in the surrounding 500 m. Community composition was mainly driven by species turnover than by nestedness, with db-RDA showing that turnover was explained primarily by urban infrastructure and forest cover. Our results indicate that urbanization negatively influences species richness. Moreover, as the amount of urbanization increased, several species were replaced by others taxa that appear better adapted to urban environments. Our results indicate that maintaining large ponds with surrounding native vegetation in urban environments might be an effective strategy for conserving frog communities.

ecology↗

bioRxiv2020

Harlequin Frogs (Lysapsus) prefer mild places to park

Temperature affects most aspects of ectotherms life history, including physiology and behavior. Studying thermal sensitivity of jumping performance in frogs can help understanding the influence of temperature on different aspects of frog life. Still, studies on the effects of temperature on amphibians are commonly carried out on terrestrial and tree species, creating a gap for aquatic species. We experimentally tested the thermal sensitivity of jumping performance of the Uruguay Harlequin Frog, Lysapsus limellum, assessing three measures: response time, distance of first jump, and total distance travelled. We hypothesized that individuals submitted to extreme temperatures would increase response time, decrease first jump distance, and increase total jump distance. We used an arena with a gradient of air temperature (Ta) ranging from 20 to 40 {degrees}C. We placed frogs at different Ta and stimulated them to jump. Then, we analysed the influence of Ta on the three estimates of jumping performance, using generalized additive models. We found that temperature affected all three measurements of jumping performance, but some relationships were stronger than others. Extreme temperatures increased response time, reduced first jump distance, and increased total distance. The effect was weaker for response time and first jump distance, but substantially stronger for total distance jumped. Although individuals under extreme temperatures experience a reduced jumping performance, they travelled longer distances to find areas with milder temperatures. Thus, we showed that L. limellum thermoregulates by means of behavior, moving through places at different thermal conditions. Additionally, benefits of displacing to thermally suitable places -in terms of enhanced jumping performance-are bigger than the costs of jumping at reduced locomotor performance, at least under experimental conditions. Our results can help understand how climate change affects the locomotor performance of Neotropical amphibians.

ecology↗

bioRxiv2020

The evolution of red blood cell shape in a continental radiation of fishes

The size and shape of Red Blood Cells (RBC) can provide key information on life history strategies in vertebrates. However, little is known about how RBC shape evolved in response to environmental factors and the role of phylogenetic relationship. Here, we analyzed RBC morphometrics in a continental radiation of fishes testing the hypothesis that phylogenetic relationship determines species occupation of morphospace. We collected blood samples of five specimens of 15 freshwater fish species from six orders and used basic stereological methods to measure cell and nucleus area, perimeter, and diameter, cell and nucleus volume, nucleus:cytoplasm ratio, and shape factor of 50 cells per specimen. Then, we conducted a phylogenetic Principal Components Analysis using a dated phylogeny and built a phylomorphospace. To test if the phylogenetic relationship predicted the phenotypic similarity of species, we calculated multivariate phylogenetic signal. We also estimated the evolution rate of RBC shape for each node and tip using ridge regression. Finally, we tested if the position in the water column influenced RBC shape using a phylogenetic GLS. RBC shape seems to have evolved in a non-stationary way because the distribution pattern of species in the phylomorphospace is independent of the phylogeny. Accordingly, the rate of evolution for shape was highly heterogeneous, with an increase in the genus Pygocentrus. Water column position does not influence RBC shape. In conclusion, RBC shape seem to have evolved in response to multiple selective pressures independent of life history characters.

evolutionary biology↗

bioRxiv2019

Idiosyncratic liver alterations of five frog species to land use changes in the Brazilian Cerrado

Changes in land use trigger environmental changes that can lead to decreased biodiversity and species loss. The liver is an essential detoxification organ that reflects systemic physiological responses to environmental changes. Here, we tested whether land use changes influence the amount of substances from the hepatic cellular catabolism and melanomacrophages of five anuran species in the Brazilian Cerrado. We used routine histological and histochemical techniques. We then use recently developed ecological methods to relate functional traits to environmental variables. There was an increase in the amount of melanin in environments with high proportion of agriculture, as well as variation in the amount of lipofuscin and hemosiderin. Therefore, the area of melanomacrophages in the liver and the metabolic products in their cytoplasm can be used as biomarkers of environmental changes in regions with intense agricultural activities. Our results add a new perspective to the influence of land use changes on environmental health by highlighting the effect of environmental changes on internal morphological aspects of animals.View Full Text

zoology↗

bioRxiv2018

Canopy cover and structural complexity affect the phylogenetic composition of a pond-dwelling Neotropical anuran metacommunity

Phylogenetic information has been increasingly included into (meta)community assembly studies. However, recent studies have challenged the framework commonly used to infer processes from phylogenetic structure. Amphibians are good model organisms to study processes promoting structure in metacommunities, since they are subjected to different environmental and spatial processes throughout their biphasic life cycle. Pond canopy cover is one of these environmental factors that strongly influence the distribution of species and traits of several freshwater taxa, including larval amphibians (e.g., behavior, color, fin height, and length of intestine). Here, I tested the influence of pond canopy cover, floating vegetation, and pond morphology on the phylogenetic structure of an anuran metacommunity in the Atlantic Forest of Southeastern Brazil. I sampled tadpoles in 13 ponds and marshes from June 2008 and July 2009 in the Serra da Bocaina National Park, Sao Paulo. After building a metacommunity phylogeny, I used an eigenvector-based technique to describe the metacommunity phylogenetic composition (Principal Coordinates of Phylogenetic Structure, PCPS). I then run a db-RDA to evalute whether a subset of these eigenvectors can be explained by environmental variables. I found that pond canopy cover and floating vegetation were the main variables influencing lineage sorting in this metacommunity. Canopy cover separated hylid lineages from other families that were associated with open areas. Floating vegetation separated two hylid tribes (Cophomantini and Dendropsophini). Our results mainly suggest that the effect of canopy cover and floating vegetation on the structure of anuran metacommunity may affect not only species, but also entire lineages.

ecology↗

bioRxiv2017

Environmental correlates of internal coloration in anurans vary throughout space and lineages

Internal organs of ectotherms have melanin-containing cells. Several studies analyzed their developmental origin, role in immunity, and hormonal regulation. However, little is known about how environmental variables influence the distribution and quantity of organ coloration. Here, we addressed how environmental variables (temperature, UV, and photoperiod) influence the internal coloration of amphibians after controlling for spatial and phylogenetic autocorrelations. Coloration in all organs was correlated with phylogeny. However, the coloration of the heart, kidneys, and rectum of hylids, R. schneideri, some Leptodactylus, and Proceratophrys were influenced by temperature and photoperiod, whereas that of the testicle, lumbar parietal peritoneum, lungs, and mesenterium of Leiuperinae, Hylodidae, Adenomera, most Leptodactylus were influenced by UVB and temperature variation. Therefore, the amount of internal melanin seems to be a key trait influencing species distribution of frogs throughout space, since it can protect internal organs against the deleterious effect of high UV-B, temperature variation, and photoperiod.\n\nSignificanceThe functions of internal coloration in fishes and frogs are little known. Internal pigmentation is commonly altered in fish and the degree of response is correlated with body transparency levels, suggesting possible adaptive functions. Here, we assume that internal melanin has protective functions against UV-B, temperature variation, and photoperiod. Thus it could influence frogs species distribution throughout space. The melanin coloration of each organ was influenced by distinct environmental variables depending on the lineages of species. Our results could direct further studies about the functions of internal coloration.

evolutionary biology↗