The dance of lights emanating from fireflies is among the most spectacular nocturnal sights in the natural world but experts have warned certain species may be at risk of extinction.
Amid a range of threats, an academic survey of firefly experts from around the world found that habitat loss is considered the heaviest pressure on the insects, which include more than 2,000 species. Pesticide spraying and the use of artificial lights at night are the other leading threats to the creatures, which are in the beetle family.
Most firefly species aren’t well documented in terms of populations, with substantial data only existing for a few, such as the common European glowworm and a separate species found in Malaysia. But these records have shown declines, raising concerns that fireflies could be facing the sort of woes that have sparked fears elsewhere of a broader crisis in the insect world.
“If people want fireflies around in the future we need to look at this seriously,” said Sara Lewis, a professor of biology at Tufts University in Massachusetts, who led the survey. “Fireflies are incredibly attractive insects, perhaps the most beloved of all insects, because they are so conspicuous, so magical.
“They spark wonder in people. When you are in your back yard or park you notice them and are amazed. They are one of the few things that universally give people a feeling of falling in love in nature.”
Lewis is leading a team of biologists associated with the International Union for the Conservation of Nature seeking to better understand the challenges faced by fireflies and help safeguard them. “We want to keep fireflies lighting up our nights for a long, long time,” said Sonny Wong of the Malaysian Nature Society, a member of the group.
Some fireflies are habitat generalists but others are at particular risk if areas are razed for residential or commercial development. Lewis said the Bethany Beach firefly, found only in a handful of wetlands along Delaware’s Atlantic coast, is an example of a firefly in such peril. “Unfortunately people also like to live on the coast and there’s been tremendous residential development there,” she said.
Juvenile fireflies develop underground or in leaf litter, making them vulnerable to insecticides used to target crop pests. Fireflies have also suffered from the explosion in light pollution over the past century, a problem that scientists have warned is driving the decline of other insects, especially moths.
On top of their incandescent beauty, fireflies are considered important in the ecosystem, preying upon creatures such as slugs and snails.
“They also play a role as a flagship species for insect conservation, because they are so attractive,” said Lewis. “People, certainly in the US, who don’t like insects would say, ‘I love fireflies and I’ll do anything to conserve them.’ We want a world where they are still around. At least with light pollution there’s an easy way to reverse things – you just turn off the lights.”