Gary O'Brien/AP

Fewer Firefly Sightings Indicate Drop in Population

September 02, 2008 03:30 PM
by Isabel Cowles
Anecdotal evidence worldwide suggests that firefly populations may be on the wane.
Reports from firefly observers worldwide indicate that there are fewer fireflies lighting up the sky than there used to be. 

According to Preecha Jiabyu, a firefly observer along the Mae Klong River, “The firefly populations have dropped 70 percent in the past three years.”

Swiss firefly researcher Stefan Ineichen asserted, “It is quite clear they are declining. When you talk to old people about fireflies, it is always the same. They saw so many when they were young and they are lucky now if they see one.”

Researchers believe that urban sprawl has reduced firefly habitats and populations. Experts also suspect that fireflies may be sensitive to light pollution, which disrupts the flashing associated with their mating behavior.

Fireflies remain a mystery on a number of levels: very little is known about the effects of fertilizers and pesticides on their habitats and researchers are still investigating the effects of streetlights on firefly mating.
But some researchers believe that firefly populations may not be declining: one theory posits that light pollution disrupts our ability to see fireflies, thereby making it seem as if there are fewer of them.

According to Carmen M. Greenwood, an assistant professor of entomology at Oklahoma State University, firefly populations may actually be on the rise in some areas due to recent warm weather trends, which produce moisture and spur the growth of insects. "Since fireflies are primarily predatory, feeding on other small insects, a general increase in insects would be likely to promote an increase in fireflies also," Greenwood said.

Furthermore, not all fireflies produce light. Only some are equipped with the luminescent substance luciferin. Because scientists cannot track firefly populations directly through light production, it is difficult to acquire a precise understanding of exact population numbers.

Reference: Fireflies at a glance

Related Topic: Bees: another endangered insect


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