Biology subjects

Villalobos, F.

Publications and source records attributed to Villalobos, F..

7 recordsLinked to original sources

bioRxiv2025

The malate aspartate shuttle supports thermogenic lipid mobilization in brown adipocytes

Brown adipose tissue (BAT) plays a central role in thermogenesis by coupling fatty acid oxidation to heat production. Efficient BAT thermogenic activity requires enhanced glycolytic flux, which in turn depends on continuous regeneration of cytosolic NAD to sustain glyceraldehyde-3-phosphate dehydrogenase activity. This regeneration is mediated by three main pathways: lactate dehydrogenase, the glycerol-3-phosphate shuttle, and the malate-aspartate shuttle (MASh). We previously showed that inhibition of the mitochondrial pyruvate carrier increases energy expenditure in brown adipocytes via MASh activation. However, the specific contribution of MASh to BAT energy metabolism remains poorly defined. Here, we show that MASh is functional and directly regulates lipid metabolism in BAT. Enzymatic activities of cytosolic and mitochondrial malate dehydrogenases and glutamic-oxaloacetic transaminases in BAT were comparable to those in the liver. Using a reconstituted system of isolated BAT mitochondria and cytosolic MASh enzymes, we demonstrated that extra-mitochondrial NADH is efficiently reoxidized in a glutamate-dependent manner via MASh. Genetic silencing of the mitochondrial carriers critical to MASh--namely the oxoglutarate carrier (OGC1) and aspartate-glutamate carrier (Aralar1) had no apparent effects on respiratory rates. However, silencing either OGC1 or Aralar1 led to the accumulation of small lipid droplets and impaired norepinephrine-induced lipolysis. Taken together, our data indicate a novel role of MASh in regulating BAT lipid homeostasis with potential implications to body energy expenditure and thermogenesis.

biochemistry↗

bioRxiv2025

PhylloTraits 1.0: Unveiling the diversity of functional traits

Functional traits play a key role in understanding species ecological and evolutionary dynamics. However, the plenty of data collected on functional traits is sparse across literature so retrieving it, especially information for tropical species, becomes a challenge. We introduce PhylloTraits, a functional trait comprehensive database from bats of the family Phyllostomidae. The New World phyllostomids are one of the mammalian families with the greatest diversity of trophic and ecological habits. In addition, this family of bats is a prominent component of mammalian assemblages in the Neotropics. Phyllotraits 1.0 compiles a data collection on wing and body morphology from 230 species at individual level. The wing morphology traits can provide insight into flight performance and maneuverability. The body morphology traits are useful in addressing ecological aspects of Phyllostomidae bats. PhylloTraits 1.0 provides efficient access to functional data collated from various sources, including published literature in English, Spanish and Portuguese, and field studies. Furthermore, PhylloTraits 1.0 includes geographic coordinates of individual data to facilitate the examination of biogeographic patterns across different regions. By uncovering and synthesizing these functional traits and capturing individual variation, PhylloTraits aims to enhance our understanding of the ecological roles, evolutionary adaptations, and conservation implications of phyllostomid bats. This database would serve as a tool for comparative studies, ecological modeling, and conservation assessments. We anticipate that PhylloTraits will stimulate further research and promote collaborative efforts to unravel the intricate relationships between functional traits, their evolution and the ecological dynamics of Phyllostomidae bats.

ecology↗

bioRxiv2024

Dogs density drives the reproductive effort of American Oystercatchers (Haematopus palliatus) in disturbed habitats of the Maule Region, central Chile

The American Oystercatcher (Haematopus palliatus) is a shorebird specialized in coastal environments across the Americas. Thus, anthropic extensive use of the shoreline including the introduction of dogs and vehicles to beaches could directly impact fitness, and ultimately the persistence of the species populations. In this study, we aimed to assess the impact of pedestrians, vehicles and dogs on the nest density, productivity and hatching success of the American Oystercatcher in the Maule Region, central Chile. To this end, we sampled sandy beaches, quantifying the number of nests, eggs, chicks, but also pedestrians, vehicles and dogs during the breeding seasons of 2023 and 2024. We assessed for the influence of these threats on parameters of reproductive output by using Generalized Linear Mixed Models. We found that the number of dogs is the only variable that negatively impacts the number of nests, eggs and chicks of the American Oystercatcher in the sampled areas. Reducing the impact of dogs is a ubiquitous challenge in coastal environments of central Chile, however current regulations do not allow management relying on removal of dogs from important areas for biodiversity.

ecology↗

bioRxiv2024

Thermal energetics of bats of the family Vespertilionidae: an evolutionary approach

O_LIThermal energetics define the way animals spend energy for thermoregulation. In this regard, numerous studies have determined that body mass (Mb) is the most influential morphological trait affecting the thermal traits in different species of birds and mammals. However, most of the studies have been focused on the basal metabolic rate (BMR), while other thermal traits have been less studied. C_LIO_LIWe addressed this gap by examining thermal variables on bats of the family Vespertilionidae. Using open-flow respirometry, we measured BMR, absolute thermal conductance (C), lower and upper critical temperatures (TLC and TUC), and the breadth of the thermoneutral zone (TNZb) of 15 bat species varying in Mb from [~] 4.0 to 21.0 g from central Mexico. We: 1) combined our empirical data with information gathered from the bibliography and conducted phylogenetic analyses to investigate the relationship between Mb and thermal traits, and 2) mapped the thermal energetic values along the phylogeny to explore how they may have evolved. C_LIO_LIWe found a positive relationship between Mb and BMR and absolute C, and a negative relationship between Mband TLC and TUC. However, we did not find a relationship between Mband TNZb in bats. The phylogenetic approach suggested that over the evolutionary history of bats, BMR and C have decreased while TLC and TUChave increased. C_LIO_LIOur results suggest that adaptive changes in Mb and thermal traits may have influenced the geographical distribution and the use of energy-saving strategies of the different species of bats of the family Vespertilionidae. C_LI

evolutionary biology↗

bioRxiv2020

Trophic guild and forest type explain phyllostomid bat abundance variation from human habitat disturbance.

The loss of tropical forest cover caused by land-use change is causing a reduction in functional groups, such as trophic guilds. Phyllostomid bats (family Phyllostomidae) are essential in the Neotropics since they occupy up to six trophic guilds, and are pollinators, seed dispersers, and regulators of vertebrate and invertebrate populations. In this study, a series of meta-analyses were performed in order to analyse their response to habitat disturbance. Data were obtained through a comprehensive literature review whereby we measured the abundance of phyllostomid bats in disturbed habitats and conserved forests. We found that the abundance of phytophagous bats depends on the type of habitat disturbance and the type of forest where it occurs. On the other hand, animal-feeding bats reduce their abundance in any disturbed habitat regardless of disturbance type and forest type. No phylogenetic signal was found in the response of bats to habitat disturbance, nor was the response found to be dependent on the type of crop, the age of the secondary forest, or the distance to a conserved forest. These results demonstrate that feeding and the type of forest where the disturbance occurs are important aspects to understand the reduction of animal populations in the face of habitat destruction processes. This has implications on the conservation of species and their function in ecosystems. HighlightsO_LINo phylogenetic signal was found in the abundance of bats in disturbed habitats. C_LIO_LIThe abundance of bats in disturbed habitats depends on the trophic guild. C_LIO_LIForest altitude influences the abundance of bats in disturbed habitats. C_LIO_LIAnimal-feeding bats reduced their abundance in disturbed habitats regardless of disturbance type and forest type. C_LI

ecology↗

bioRxiv2019

Testing Darwin's naturalization conundrum based on taxonomic, phylogenetic and functional dimensions of vascular plants

Charles Darwin posited two alternative hypotheses to explain the success of nonnative species based on their relatedness to incumbent natives: coexistence between them should be (i) more likely with greater relatedness (due to trait similarity that correlates with better matching to the environment), or (ii) less likely (due to biotic interference, such as competition). The paradox raised by the opposing predictions of these two hypotheses has been termed Darwins naturalization conundrum (DNC). Using plant communities measured repeatedly over a 31-year time span across an experimental fire gradient in an oak savanna (Minnesota, USA) we evaluated the DNC by explicitly incorporating taxonomic, functional and phylogenetic information. Our approach was based on focal-species such that the taxonomic, functional and phylogenetic structure of species co-occurring with a given nonnative species in local communities was quantified. We found three main results: first, nonnatives colonizers tended to co-occur most with closely related incumbent natives in recipient communities, except in the extreme ends of the fire gradient (i.e., communities with no fire and those subjected to high fire frequencies); second, with increasing fire frequency, nonnative species were functionally more similar to native species in recipient communities; third, functional similarity of co-occurring nonnatives and natives in recipient communities showed a consistent pattern over time, but the phylogenetic similarity shifted over time, suggesting that external forces (e.g., climate variability) are also relevant in driving the phylogenetic relatedness of nonnatives to natives in invaded communities. Our results provide insights for understanding the invasion dynamics across environmental gradients and highlight the importance of evaluating different dimensions of biodiversity in order to produce more powerful evaluations of species co-occurrence at different spatial and temporal scales.

ecology↗

bioRxiv2016

Challenging the Raunkiaeran shortfall and the consequences of using imputed databases

O_LIGiven the prevalence of missing data on species traits - Raunkiaeran shorfall -- and its importance for theoretical and empirical investigations, several methods have been proposed to fill sparse databases. Despite its advantages, imputation of missing data can introduce biases. Here, we evaluate the bias in descriptive statistics, model parameters, and phylogenetic signal estimation from imputed databases under different missing and imputing scenarios.\nC_LIO_LIWe simulated coalescent phylogenies and traits under Brownian Motion and different Ornstein-Uhlenbeck evolutionary models. Missing values were created using three scenarios: missing completely at random, missing at random but phylogenetically structured and missing at random but correlated with some other variable. We considered four methods for handling missing data: delete missing values, imputation based on observed mean trait value, Phylogenetic Eigenvectors Maps and Multiple Imputation by Chained Equations. Finally, we assessed estimation errors of descriptive statistics (mean, variance), regression coefficient, Morans correlogram and Blombergs K of imputed traits.\nC_LIO_LIWe found that percentage of missing data, missing mechanisms, Ornstein-Uhlenbeck strength and handling methods were important to define estimation errors. When data were missing completely at random, descriptive statistics were well estimated but Morans correlogram and Blombergs K were not well estimated, depending on handling methods. We also found that handling methods performed worse when data were missing at random, but phylogenetically structured. In this case adding phylogenetic information provided better estimates. Although the error caused by imputation was correlated with estimation errors, we found that such relationship is not linear with estimation errors getting larger as the imputation error increases.\nC_LIO_LIImputed trait databases could bias ecological and evolutionary analyses. We advise researchers to share their raw data along with their imputed database, flagging imputed data and providing information on the imputation process. Thus, users can and should consider the pattern of missing data and then look for the best method to overcome this problem. In addition, we suggest the development of phylogenetic methods that consider imputation uncertainty, phylogenetic autocorrelation and preserve the level of phylogenetic signal of the original data.\nC_LI

evolutionary biology↗