Dr. Luis Fernando De León
Postdoctoral Researcher

Future Research

a) Darwin's finches
Two important implications emerge from my previous and ongoing research. First, inter-specific hybridization could be playing an important role in the adaptive diversification of Darwin's finches by generating high levels of morphological and genetic variation which is then targeted by natural selection. And second, human disturbances might be weakening boundaries not only between divergent populations within species but also among species. The entire Galápagos Archipelago has experienced a dramatic increase of human activities, but it is unknown how this might be altering the rugged adaptive landscapes that used to maintain separate populations/species.

My future research plans, therefore, concentrate on how both natural ecological variation and anthropogenic disturbances can influence the patterns of gene flow and hybridization. My focus will be on the closely-related species of Ground finches living on the four human populated islands in the archipelago. If human activities influence the evolution of these species, I anticipate a decrease in morphological, genetic and ecological differences among species in disturbed relative to undisturbed sites on each island. These differences may vary with the level of perturbation and could result in variable levels of gene flow and hybridization. A group of species so important to our original understanding of evolutionary processes since Darwin's visit to the Galápagos could now prove important for understanding how humans alter those processes and thereby modify future evolutionary trajectories.

Some Darwin's finches can exploit novel human food items. For instance, this medium Ground finch was photographed while eating rice from a feeder in Puerto Ayora, Santa Cruz Island. My research suggests that humans could be affecting the process of adaptive radiation in Darwin's finches. (Photo credit: L. F. De León)

a) e-fishes

The so called, electric fishes, members of the Order Gymnotiformes, produce a bioelectric field through the discharge of an electric organ (EOD). These signals are used to localize objects and prey, and are involved in mating and social interactions. In addition, fish use the bioelectric fields to discriminate con- from hetero-specifics. This suggests that these electric signals may be analogous to the song used by Darwin's finches. If so, they could play an important role in generating the evolutionary trajectories and diversification of these fresh water species. On the one hand, natural selection may be acting on these bioelectric fields to optimize habitat use and survival. On the other hand, sexual selection may be acting on this trait to optimize mate choice and reproductive success.

In this project, I attempt to unravel these processes and study how their interaction has shaped the diversity of electric signals along the phylogenetic tree of electric fish species. Specifically, I will use mark-recapture experiments and population genetics to study the patterns of survival (natural selection) and mate choice (sexual selection) in relation to variation in fish morphology and electric signals in the streams of Panama. This research will ultimately lead to a better understanding of the processes that promote the diversity of these the neotropical fresh water fishes. This works will be in collaboration with Dr. Rudiger Krahe at McGill University.

Summary of previous research | Research in progress | Future research