Research

Our mission is to understand the role of spatio-temporal heterogeneity on species interactions at multiple scales through the integration of theoretical modeling and empirical data. To fulfill this mission, we follow an interdisciplinary approach that integrates knowledge from ecology and molecular biology with applied mathematics, and statistics. (updated by QuantLab Fall 2016).

We are particularly interested in looking at how spatial heterogeneity influences meta-population dynamics of mosquito-borne diseases in human and non-human hosts.

In our approach we collaborate with mathematicians to develop theoretical models. We test the predictions of these models using field data from observational studies or field experiments. We then use this knowledge to develop quantitative applications that can be used for biodiversity conservation or disease control.

Three research directions

Virulence Evolution

The theory of virulence evolution states that virulence-the harm that a pathogen inflicts on its host through a decrease in host fitness—is an unavoidable cost to the pathogen for using the host resources for replication. Under this constitutive theory, the trade-off hypothesis predicts that the cost of increasing within-host replication results in a deceleration in transmission-rate because increasing within-host replication rate increases mortality rates, which ultimately translates into a shorter infectious period at the population level. The original proponents of the trade-off hypothesis argue that the trade-off curve will be less common in vector– and water-borne diseases because the potential of virulence decreasing host mobility becomes less relevant when vectors are the ones transmitting the pathogen between hosts. In collaboration with the Elderd Lab at LSU we are conducting a meta-analysis of the literature to test if these ideas can be generalizable across host-parasite systems. In the lab we are also conducting empirical research on these issues. David is quantifying the potential negative impacts of Plasmodium azurophilum on the Puerto Rican Yellow chinned anole. Nicole is quantifying the potential negative impacts of Plasmodium infection on Puerto Rican urban birds.

Interacting heterogeneities and VBD outcomes

The classical theory of vector-borne disease (VBD) transmission made multiple simplifying assumptions, such as spatial homogeneity and homogeneous biting, to 11 describe the interaction between vectors and hosts. This theory was instrumental in 12 the identification of the key epidemiological factors that drive transmission in humans, helping to improve malaria control programs at the beginning of the 20th century. Recent theoretical frameworks are beginning to emphasize the importance of host heterogeneities in the ecological processes driving transmission. Understanding how spatial and demographic heterogeneities affect transmission and control is especially important as countries approach elimination, and as the world pursues regionally-organized elimination strategies. In collaboration with Olivia Prosper (Mathematics) and Nick Ruktanonchai (Geography) we are developiong theoretical models that account for individual, spatial and movement heterogeneity to study how these influence vector-borne disease outcomes. In the near future we will test predictions from these models with empirical data on human and lizard malaria.

Life-history trait evolution in secondary habitats

Populations live in a dynamic spatial and temporal equilibrium with their environment, which includes biotic interactions and abiotic factors. Among these abiotic factors, large-scale disturbances, like intensive agriculture, can disrupt this equilibrium altering ecological and evolutionary processes often resulting in local fauna extinctions. Current socio-economic changes are shifting disturbance regimes and land-use practices driving agricultural land abandonment. These abandoned lands undergo secondary succession and as they mature they can meet the minimum requirements for re-colonization of locally extinct fauna. In this collaboration with Riccardo Papa we follow an interdisciplinary approach that combines an observational (chronosequence) study, a field experiment, demographic modeling and genomic analyses to study Anolis gundlachi-a shaded-forest-specialist lizard re-colonizing secondary forests following large-scale forest recovery in Puerto Rico.