​

     1) Evolutionary ecology of ant-plant interactions

       Ecologists have been increasingly appreciating the role of tri-trophic interactions in structuring communities, in which the ant-plant mutualism mediated by extrafloral nectaries (EFNs) is a classic study model. Many studies have tested the defensive role of ants. However, it is poorly understood the influence of many abiotic and biotic factors in the outcomes of the ant-plant interaction mediated by EFNs, which is paramount for understanding the ecology and evolution of these interactions. Different theories have been proposed to explain EFN evolution and functionality. There is an extensive literature related to the ant-guard theory, but very few studies testing other theories, such as the exploitation hypothesis, ant-distracting hypothesis, and flower-distraction hypothesis. Studying the evolutionary processes inherent in ecological interactions helps us to understand how these interactions shape the biodiversity patterns and ecosystem dynamics. My research evaluates these ecological evolutionary hypotheses, but mostly focusing on the flower-distraction hypothesis of EFNs in natural systems, observing if the location of EFNs on the plant, the identity of associated organisms (plants, ants and pollinators), and the complex pollination process are related to EFN functionality.

 

 

 

 

 

 

 

 

 

 

    2) Multi-scale effects on plant-herbivore interactions

      Ecological interactions are one of the major mechanisms responsible for the maintenance of species diversity and coexistence. For instance, mutualistic and antagonistic interactions are considered drivers of species coexistence. Insect herbivores (i.e., antagonists) and pollinators (i.e., mutualists) can be highly impacting plant fitness, but the extent of this impact is highly context dependent. At large spatial scales, climate or resource availability may be important predictors of herbivore and pollinator effects on plant fitness. At local scales, conspecific density can be an important predictor of herbivore and pollinators effects. However, it is not well known the impacts of plant conspecific density along with variations in resource availability on plant resource allocation (e.g., growth-defense trade-off) and fitness. My current postdoctoral work with Drs. Phil Hahn (University of Florida) and John Maron (University of Montana), funded by an NSF grant, is evaluating how different variables (e.g., water availability, pathogens presence and conspecific density) can influence plant resource allocation, modifying the growth-defense trade-off. Using Monarda fistulosa (Lamiaceae) as a focal plant species, we sampled populations in different resource regions: a low-resource region in Montana with cooler temperatures and low summer precipitation, and a high-resource region in Wisconsin with warmer temperatures and 3-fold greater precipitation. At large scales, we found that seed loss was approximately 2-fold greater in the high-resource region compared to the low-resource region. At local scales, conspecific density was correlated with greater seed loss and seed damage in both regions, but with greater magnitude in the high-resource region, suggesting a role of negative density dependence, and context dependent outcomes. A supplementary seed addition experiment showed that seed limitation was also greater in the high resource region, suggesting that pre-dispersal seed predation might limit population size in the high resource populations. Taken together, these data suggest a predictable influence of environmental context (large scale) and conspecific density (local scale) on herbivore pressure with greater negative impacts in high-resource regions. These results improve understanding of context-dependent herbivory and the negative conspecific density dependence process.  

       Negative density dependence (NDD) – I am leading and developing three aspects of this NSF project using manipulative experiments to test the hypothesis that conspecific negative density dependence affects the growth-defense trade-off in Monarda fistulosa (Lamiaceae). I am testing conspecific NDD effects by growing plants in pots and using a factorial approach based on genotype, density, drought stress, and pathogens addition; and by using seed addition experiments and doing large-scale field surveys in regions with different resource availability. Results of this project will advance our understanding of how different environmental factors, either abiotic and biotic, have influenced the evolution of plant-herbivore interaction, mainly clarifying our understanding about how plants allocate their resources in regions with high competition, low resource, and high presence of natural enemies. I will continue to pursue research questions related to NDD, in addition to contribute and develop projects to internal grants.  

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

 

3) Climate change and anthropogenic disturbance effects

       Although climate changes and anthropogenic disturbances represent some of the main factors responsible for the loss of biodiversity and ecosystems imbalance, few studies have evaluated the impacts of these factors on the ant-plant mutualism mediated by EFNs. My research evaluates how climate change and anthropogenic disturbance can influence the composition and diversity of ants and arthropods (such as pollinators and insect herbivores) associated to EFN-bearing plants, the foraging behavior and the protective effectiveness of ants, and finally the cascade effects on the system, but especially on the development and fitness of plants. My research applies experimental manipulations in field and laboratory, and uses field observations at local, regional, and global scales to better understand the effects of climate change and anthropogenic disturbances on the ant-plant mutualism mediated by EFNs. Florida has a great diversity of EFN-bearing plants, latitudinally distributed in a gradient of climatic variables and levels of urbanization. Therefore, FL is an advantageous place to test these hypotheses and plan future studies within this topic. My study is also extended to a global level, focusing on tropical areas, such as Brazil, which bears hotspots of biodiversity, like the Brazilian Cerrado, Atlantic forest, and “Caatinga”.  

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

     

4) Pollination-herbivory balance

       Central to understand the positive and negative effects of ecological interactions acting simultaneously on the same plant is studying the balance between pollination and seed predation, and how different environmental variables can drive this balance. Although there is an extensive literature showing the effects of mutualistic or antagonistic interactions on plant fitness, the cumulative effects of both types of interactions are poorly known. Since resource availability and conspecific density represent important factors driving insect diversity and abundance and plant resource allocation, using resource gradients is an advantageous way to test my hypothesis that positive effects of pollination override the negative effects of seed predation in high-resource regions and when in high densities, but not in low-resource regions and when in low densities. In future work, I plan to survey and manipulate the presence of pollinators and seed predators at community level in plants present in regions with different resource availability and in different densities.