Research Projects

Fitness is determined from the phenotypic expression of the genotypes, as functional performance, leading to survival and reproduction. This parameter is essential for understanding evolutionary processes, as it determines the directionality of natural selection, as well as its intensity. Measurement of fitness involves estimates of survival and reproduction, as well as their relation to genetic variants in a population. It is not always easy or possible to measure these components in a natural population, and it is necessary to find indirect measures (proxies) that are related to fitness and are valid in different situations. This project aims to test hypotheses about different phenotypic and functional variables potentially associated with components of fitness such as survival and reproduction using phylostomid bats as study models. These characters are expressions of genotypes that are associated with the individual's functional performance, such as asymmetry in body structures, body condition, bite force, and the bioacoustic structure of social vocalizations. Our research team studies a colony of short-tailed bats Carollia perspicillata (Phyllostomidae) marked and released for later recapture and monitoring of their longevity and reproduction. We use mark-recapture Comarck-Jolly-Seber (CJS) models with heterogeneity and generalized linear models to estimate survival and its relationship with phenotypic and functional variables. The monitoring of the marked animals in the long term will also allow the improvement of marking techniques in bats, but mainly the expansion of the range of evolutionary and ecological issues associating phenotype and fitness, even with the use of collection material.

Bats present great morphological and ecological variability, but facing a constant flight related restriction towards skull shape disparity, as they need to stay light, even when executing functions which require cranial robustness (such as the mastication of harder food items). This skull optimization necessity linking shape, function and ecology makes bats an ideal group to study and test hypotheses on the functional consequences of integration and shape evolutionary shifts and on the ecological diversification of adaptive radiations. The main aim of this project is, by combining morphometrics, quantitative genetics and phylogenetic comparative methods, to understand how bats skull ecomorphological diversification patterns originates from modifications in developmental and functional patterns in the level of individual organisms. The relevance of this project resides in the fact that it deals with a fundamental issue on how complex morphologies evolve. The implications underlining its results are vast, not only viewing the production of basic knowledge, but also analytical tools.

Medium and large mammal communities have been widely used as indicators of conservation status in tropical forests. These species play important roles in the ecosystem services of seed dispersal, population control of herbivores and even nutrient cycling, which can cause considerable changes in the structure of forests and the dynamics of regeneration of degraded areas. In this context, automatic photographic traps emerged as tools for the detection of rare species and estimates of abundance based on occupation rates, allowing for more detailed population studies and a more complete view of the community structure. Monitoring the spatiotemporal distribution of key species can thus be performed remotely and for long periods of time, generating invaluable data sets. Another benefit of using traps is the possibility of using videos, which in addition to favoring the identification of species in some cases, also allow the monitoring of intra-specific behaviors and interactions between species. The main objective of this research project is to estimate population parameters (occupation, abundance, density, activity patterns and functional diversity) of medium and large-sized mammal species in the Atlantic Forest (mainly at União Biological Reserve), as well as their distribution, preference for habitats and how the level of protection of the fragments influence these parameters. We intend to establish a long-term monitoring protocol to detect population fluctuations, in view of the conservation challenges that are observed both within and around the Reserve.

In geographically widely-spread clades, like the carnivorans of South America, traits may vary across a climatic gradient. This variation can be potentially explained by ecogeographical rules, such as Bergmann’s and Resource rules, and by allometric rules, like Rensch’s rule. Bergmann predicted that an enhance of body size would be selected at higher latitudes (colder environments) as an adaptation to avoid heat loss to the external environment. Resource’s rule foresees that size increases in relation to patterns of variation, in space and/or time, of the type and amount of resource available at different areas, creating conditions that may favour animal growth rates. Lastly, Rensch’s rule predicts that the enhancement of sexual dimorphism is associated to the increase of species size. Given these, sexual dimorphism could interact with ecogeographical patterns. Although these ecogeographical rules were originally described in relation to animal size variation, their idea can potentially be extended to animal shape as well. This is due to the fact that animal shape (especially their feeding apparatus) has a functional component that is related to animals feeding ecology, in addition to the intrinsic association of size and shape variation (= allometry). Within this context, we propose to evaluate the association of allometry, climatic variation and sexual dimorphism in the mandibular morphology of South-American carnivores. In order to understand how ecogeographic and allometric rules associate within a macroevolutionary context, we intend to analyse the mandible shape variation of twenty species of Carnivora. We planned a stepwise procedure of analytical models that will work interactive between intra and interspecific data in order to analyse allometric, ecogeographical and sexual variation at different scales. This framework can potentially be suitable for multiple biological models, contributing for the advances of evolutionary studies at large scales.