Flashing ‘predatory rovers’ discovered in Pennsylvania are new species, study says

Two new species of predatory fireflies were recently discovered throughout parts of the northeastern United States.

The light-emitting beetles were found flying over farms and fields in Pennsylvania and Delaware during a multi-year survey, according to a study published in the journal Northeastern Naturalist.

Both species were found to belong to the genus photoris, a family of femme fatale lightning bugs which lure males in with their glow in order to kill and eat them, according to iNaturalist, a citizen scientist platform.

Unlike other fireflies that remain in one particular location, both of the newfound species are predatory rovers, meaning they travel far distances to find mates and prey.

After observing their unique flashing patterns, Christopher Heckscher, the study author, captured specimens using a hand lamp and net. They were then placed in ethanol and further analyzed.

The first species, named witmeri, was found at night, flying low over vegetation in several Pennsylvania counties and one county in Delaware.

It emitted a single flash, followed by a longer, trembling flash, according to the study.

The specimens, which were brown and orange in color, had “a noticeably large width to length ratio.”

Based on how few specimens were found, they should be considered “rare or uncommon” in the region, Heckscher said in the study.

The second species, named figuramuto, was found only in Pennsylvania, and it bore resemblance to witmeri. It emitted “a single bright flash at irregular intervals,” according to the study.

“These observations show the ability of this species to alter flash patterns perhaps in response to the presence of other firefly species,” the study author said.

Throughout North America, there are around 150 species of fireflies within 16 genera, and they are often difficult to tell apart, according to the Massachusetts Audubon Society.

This story was originally published January 5, 2024 at 10:40 AM with the headline "Flashing ‘predatory rovers’ discovered in Pennsylvania are new species, study says."