Longer male flashes attract female fireflies, Tufts study finds

New research by a Tufts professor and a Tufts graduate gives scientists more clues about the communication and mating habits of fireflies.

The research project, led by Biology Professor Sara Lewis and Christopher Cratsley, a 2000 Tufts Ph.D. graduate who is now a biology professor at Fitchburg State College, involved the participation of two undergraduates and was sponsored by the National Science Foundation.

The collaborative study found that female fireflies are strongly attracted to males who give long flashes or signals. Longer flashes indicate that the males are able to be better fathers because they can provide more prenatal nutrition for their offspring. This nutrition, also known as the nuptial gift, is like "child support for fireflies," Lewis said.

Since fireflies only live for two weeks as adults, Cratsley said, their focus is entirely on courtship and mating. This single-mindedness and focus on procreation is part of what makes fireflies so valuable in studying evolutionary processes.

Fireflies "have no distractions," according to Lewis.

The inclusion of undergraduates on a research team is not something new for the biology department. Every summer since 1991, Lewis and her colleagues have been sponsoring undergraduate research on fireflies, and nearly a dozen undergraduate students have had the opportunity to participate so far.

"Part of what makes the University such a great place to do research is that undergraduates have many opportunities to work with professors in the area they are interested in," Lewis said. "Faculty here realize that part of the undergraduate experience is to see how science is done."

Even more undergraduates will be able to take part in the study of fireflies this summer when Lewis and Biology Professor Ross Feldberg lead a project on the biochemistry of firefly mating as part of the Summer Research Experience for Undergraduates (REU).

The REU program, sponsored by the National Science Foundation, will be offered from May 26 to Aug. 1. In addition to research, professors will lead weekly discussions, seminars, field trips, and a symposium.

The biology department started actively researching the signaling and mating habits of fireflies and the effects of nitric oxide on fireflies in 2001. Lewis and Biology Professor Barry Trimmer, a neurobiologist, led research that received a strong response in the science community as well as coverage by CNN after it was published in the June 2001 issue of Science.

This most recent firefly study was published in the Jan./Feb. issue of Behavioral Ecology.

Since its publication, Lewis and Cratsley's study has received coverage by Reuters, MSNBC, National Public Radio, CNN Online, and Yahoo. The high interest in the study is a result of more than ten years of various research projects and the fact that, according to Lewis, "Everyone loves fireflies."

The biology department at Tufts is largely unique, Lewis said, in that it covers "the whole gamut of biology across different disciplines and encourages collaborative work." The ability to do "cutting edge research at every level" is part of what makes Tufts such a valuable institution, he said.