Generales

By: Andrea Carolina Vargas Malagón - Journalist

Iridescence and its relationship with the evolution of Morpho butterflies is the central theme of a new research project in which UdeA participates. Marco Antonio Giraldo Cadavid, coordinator of the University's Biophysics Group, was selected for the 2023 International Human Frontier Science Program research grants. The project will be developed with researchers from three other countries and will be funded with 1.5 million dollars.

Morpho sulkowskyi inhabits eastern Antioquia and can be seen in the village of Santa Elena. Photo: Courtesy of the Biophysics Group

It seems as if they changed their costume from time to time: at each flap of their wings, when they perch in front of the sun's rays or during their rest under the shade of a tree. This optical phenomenon, known as iridescence, is caused by multiple reflections of light on semi-transparent surfaces. It is characteristic of butterflies of the genus Morpho.

Is this iridescence related to their flight patterns? Does it influence their courtship or territoriality rituals? Does it help them avoid predators? These are some of the questions that Marco Antonio Giraldo Cadavid, professor and researcher of the Biophysics Group, attached to the Faculty of Exact and Natural Sciences of Universidad de Antioquia, has now set out to solve.

Together with three other international researchers, Giraldo, who holds a PhD in physics, was recently selected by the European organization Human Frontier Science Program (HFSP) as one of the winners of the 2023 grants for collaborative research, whose general theme for this version was "Complex mechanisms of living organisms."

The award-winning researchers will develop the project "Physics Goes Wild: Studying the Evolution of Iridescence and Its Perception in Amazonian Butterflies," for which they will receive a grant of 1.5 million dollars. "We are four researchers from different countries who aim to understand the evolution of color in the genus Morpho from different perspectives and fields of expertise," explained Giraldo, who has devoted much of his research work to studying the generation of color in nature. The other three partners in this study are Gregor Belušic, from Slovenia, an expert in visual perception; Adriana Briscoe, from the United States, a specialist in molecular biology; and Vincent Debat, from France, who specializes in flight.

The four researchers of this interdisciplinary and complementary study on the evolution of iridescence and its perception, performed on Amazonian butterflies, will devote the next three years to finding the correlation between coloration, vision, flight and genetic evolution of the 30 species of Morpho butterflies. These are exclusive to the Neotropics; 24 are in Colombia, and six inhabit Antioquia.

The research project on the evolution of iridescence in Morpho butterflies submitted to the HFSP was among the 25 funded proposals of the applications submitted to the call. The 34 winning teams in the 2023 research grant competition underwent a rigorous year-long selection process in a global competition that began with 589 letters of intent that involved scientists with labs in more than 50 countries. The frontier science of life knows no boundaries, as other winning teams propose to investigate, for example, how to harness the energy network of a cell, the electric fields at the heart of enzymatic catalysis, or robotics and pollination.

"We want to discover how Morpho butterflies see color and how this is associated with flight. For example, will they see blue one way if they flap very fast, and if they flap more slowly, another way? We also want to explore whether this is associated with how the female sees the male or how the male sees another male. The way that color is presented in flight has an evolutionary reason," Giraldo emphasized.

The scales of Morpho butterflies are 100 micrometers in size, that is, one-tenth of a millimeter. Photo Courtesy: Biophysics Group

This new research project continues a study previously carried out by the Biophysics Group with researchers from Japan, the United States and the Netherlands. The Journal of Experimental Biology highlighted the results of this study in 2016. "In that first part of the research, we concluded that, depending on the organization of the nanostructures of butterfly wings, it is possible to identify which are more recent in evolutionary terms, and which are older. For example, the fewer chitin nanocoatings the wing scales have, the more ancient they are," said Giraldo.

"The scale structures on the wings of Morpho have 2 to 10 nanoscopic chitin sheets that, when interacting with light, reflect the characteristic blue color of these butterflies." Marco Giraldo.

The International Human Frontier Sciences Program will transfer the 1.5 million dollars to conduct the research to the four institutions to which the project's researchers are linked. In addition to Universidad de Antioquia, these institutions are the National Museum of Natural History of France, the University of Ljubljana and the University of California. 

The Center for Research in Exact and Natural Sciences (CIEN) will manage the sum UdeA will receive, which amounts to US$125,000 annually.

"We are going to have money to provide scholarships for PhD, master's degree and undergraduate students as young researchers. We can also buy new equipment that will be useful for other research. This is a great help for the training of our students," said Marco Giraldo.