The iridescent blue male sunburst cerulean-satyr butterfly has been known for more than a century. But a more recently discovered dull brown butterfly was given a completely different species name.
However, an international team of nine butterfly researchers used DNA “bar code” sequence data to prove that the dull brown butterfly is actually the female cerulean-satyr butterfly.
Males and females look dramatically different from one another, a phenomenon called sexual dimorphism. This is common in birds, where, for example, the male Anna’s Hummingbird is very bright and flashy, whereas the female’s feathers boast a much more muted color palette.
The classification mistake with the butterflies probably occurred because the brown butterflies are rare than the blue ones, and because sexual dimorphism is not common in most species of butterflies.
The research team collected and analyzed DNA bar codes—short, diagnostic gene sequences—for more than 300 species across the euptychiine group of butterflies that includes the sunburst cerulean-satyr. It turned out that the DNA sequences for the sunburst cerulean-satyr and the dull brown butterfly, which had been given a completely different species name, were identical.
“None of us thought about this possibility before, and we were all surprised by this outcome of our DNA analysis,” said study lead author Shinichi Nakahara of the University of Florida. “Given that males and females of most euptchiine butterflies look more or less the same, I guess no one thought that the female would look so different compared to the male.”
The discovery of the female sunburst cerulean-satyr butterfly contributed to the recognition of the male and female of two other species in this group, including a new species from the cloud forests in eastern Ecuador. The different-looking males and females of the two species means that the euptchiine group of butterflies is one of the most sexually dimorphic among the species.
A better understanding of the diversity and relationships among euptchiines makes it possible for scientists to think about bigger questions like why and how they diversified and the role wing patterns play in signaling between the sexes, Nakahara said.
“Our study will serve as the basis for developing a firm understanding of the true species diversity of this group and of Neotropical butterflies in general,” Nakahara said. “These findings are extremely valuable at a time when the biodiversity of the Neotropics is threatened, since it will be impossible to recognize and document the region’s unique elements of biodiversity after they are gone.”