How Did Butterflies Evolve? Their Color Chemistry Offers Clues

orange butterfly with wings folded on a log
A female Elymnias hypermnestra tinctoria from Thailand. Photo credit: Nopporn Pimpakorn.

When biology professor and butterfly researcher David J. Lohman (GC/CCNY, Biology) came to The City College of New York, Professor George John (GC/CCNY, Chemistry and Biochemistry) reached out.

“I told him I was fascinated with the rainbow colors of butterflies, and this curiosity led me to catch butterflies and examine them while growing up in India,” says John, whose own research focuses on using naturally occurring molecules to develop new and functional materials through chemistry. “I said he should contact me if he ever wanted to collaborate.”
 
Nine years later, the two researchers have collaborated on a study that takes a close look at the chemical composition of the pigments in butterfly wings. The study examines two populations of female Elymnias hypermnestra butterflies with orange wings; one population from Indonesia and the other from Thailand. The chemistry can give clues as to how these colors and patterns evolved.

 Their study appears in the journal PLOS One.
 
Almost every species in the Elymnias genus mimics the colors of a butterfly that tastes bad to predators — an evolutionary survival tactic. Different Elymnias species copy different distasteful species, resulting in a huge array of colors and wing patterns across the genus.
 
“A long-term goal is to understand the genetic and developmental basis of such incredible wing pattern diversity and how it evolved within the genus,” Lohman says.
 
In their study, the scientists found that while both populations are mimics of Danaus butterflies and their shades of orange are similar, the colors arise from different pigments.
 
“Things are not always what they seem," Lohman says. “This may be the result of parallel evolution, in which evolution has acted on the same set of pre-existing genes to produce orange pigments that are chemically distinct but visually similar.” The researchers’ findings could mean that while both groups evolved to mimic the same orange species, they did so differently because of their different environments.
 
Lohman is now part of a collaboration studying the genetics of color differences within the E. hypermnestra species, an endeavor the researchers hope will later help to understand the color diversity in other species, too. He is currently on sabbatical leave, conducting fieldwork and outreach in Southeast Asia for the multi-institution collaboration ButterflyNet. The project studies the evolutionary history of all butterflies using genetic data.
 
Silvio Panettieri, a postdoctoral research associate at the Advanced Research Science Center at The Graduate Center, CUNY, and Macaulay Honors College graduate Erisa Gjinaj were lead authors on the study.

Submitted on: OCT 24, 2018

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