Bragging Lights

The length of a male firefly’s flash is a mating boast to females, say researchers from Tufts.

Medford/Somerville, Mass. [04-22-03] In 2001, Tufts research explained for the first time how the flash of a firefly works. But no one knew what the fireflies were saying with their flash, until now. In a new study, Tufts scientists discovered that the length of a male firefly’s flash is a special mating boast to females.

“A study by biologists at Tufts University shows that in one firefly species, mating preferences are based in part on the duration of the flash,” reported the New York Times. “Simply put, females make passes at males with longer flashes.”

According to Tufts researchers, the longer the flash of a male firefly, the better chance it has to mate.

“Scientists at Tufts noticed that certain firefly males have a long-lasting flash than others – and that the flashier males have more success mating,” reported the Los Angeles Times.

Sara Lewis – an associate professor of biology at Tufts and the lead author of the study – says that the length of the flash is correlated to what the male can offer the female. “It seems the longer the flash is related to the quality of the ‘nuptial gift’ he can give to his mate, says Lewis,” reported The Boston Globe.

It’s exciting news for the Tufts biologist, who began investigating the insect years ago and was part of the team of Tufts researchers which cracked the mystery of how fireflies light up in 2001.

“We have been studying fireflies because they are such cool creatures,” Lewis said in an MSNBC report. And their research can help us better understand other living things – even ourselves.

“Studying how fireflies ensure that their genes are passed on to the next generation gives us insight into how other organisms, including humans, act,” Lewis told Reuters, in a story that ran in newspapers across the country as well as around the world in news outlets in Iran, South Africa, and Pakistan.

The Tufts professor – who worked with Tufts graduate Christopher Cratsley on the project – said that the most remarkable part of the new research is the link between the length of the flash and the quality of the male’s nuptial gift, a nutrient package transferred to the female.

“What’s really new is the link between the length of male signaling and the nutrient package the male provides,” Lewis said in an ABC News report.

Lewis says that the longer the male’s flash, the bigger the nutrient package – known scientifically as a spermataphore – he has to offer the female.

“[The spermatophore’s] nickname is ‘a nuptial gift,’” Lewis said in a CNN report. “These are basically like nutrients that the males provide to females at mating. In the case of fireflies it is a very, very fancy package that contains sperm and contains proteins that are transferred to the female and later incorporated into the female’s eggs.”

Female fireflies are likely to choose the male with the longest flash – and thus the largest ‘nuptial gift.’ “You can think of it as child support,” Lewis joked.