Video screen capture Radim Schreiber/YouTube
After years of a seeming decline, reports of firefly flurries have lightning bug lovers delighted.
For years, those of us who have the pleasure of seeing our backyards light up with the magic of fireflies have been lamenting what certainly seems like a decline. Shrubbery that once twinkled like kitschy Christmas trees seems to only offer sad intermittent flickers; the solo flitting of occasional fireflies across lawns and meadows feels like some existential French film, insect-style.
Habitat destruction, agro-chemicals and light pollution seemed to have taken their toll, potentially erasing the bioluminescent beauties whose importance in sparking wonder and creating an early connection to the natural world can not be underestimated.
But this year? This year might be different.
Dale Bowman at the Chicago Sun-Times noticed what felt like an uptick in lightning bugs and anecdotal accounts from social media were in agreement. Doug Taron, the chief curator of the Chicago Academy of Sciences, noted on Facebook: ‘‘I don’t have anything quantitative, but my impression from where I live in Elgin is that it’s a very good year for fireflies.’’
When asked how that might work, Taron wrote: ‘‘Insect numbers jump around so much from year to year that it can be hard to ascribe a reason why any given year is particularly good or bad. I think the reasonably wet spring that we had probably helped keep populations of prey for their larvae [earthworms, tiny snails, and other similar critters] fairly high.’’
Digging further, Bowman contacted Derek Rosenberger, a scientist working on the insect collection at Olivet Nazarene University.
‘‘Funny you should ask,’’ he replied to Bowman. ‘‘To be honest, I was looking for them this year because there has been so much in the press about there seemingly being fewer now than there have been.’’
‘‘Compounded with that is the fact that so many insects have cyclic population trends,’’ he wrote. ‘‘They go up due to good climate/conditions/lack of predation or disease, then they come down as those things catch up with them."
"Fireflies also peak and decline during the summer," Rosenberger added. "So if you happened to be outside a lot in the evening as a kid, you likely saw the peaks, whereas if you are staying inside as an adult, you might not catch that peak. So you have to be careful about reporting declines because it might be a natural cycle.’’
He noted that there is a lot of research and surveys dedicated to pollinators like bees and butterflies, but not so much on the ecology or population dynamics of fireflies.
That said, he discovered research from Michigan State on data collected from traps set for pests.
‘‘What [author Sara Hermann] and her colleagues found is that fireflies seem to prefer less disturbed fields . . . and that they seem to be on a six- to seven-year population cycle, with us just now starting to come out of a low,’’ he emailed.
‘‘This cycle seems similar to what has been observed in a longitudinal study in Asia. So that is some evidence for anecdotal reports of a seeming increase this year. I don’t think we really know what factors (predation, disease, etc.) cause highs and lows, so regarding what factors may be leading to an upswing, I think that still needs to be investigated.’’
So while the bottom line here may be vague, the idea that their decline could potentially be just a cyclical occurrence gives rise to hope. And while the cynic in me isn’t so sure how any delicate creature can survive the onslaught of chemicals, climate change and habitat destruction that mankind seems hell-bent on perpetuating, my love for the sparkle of fireflies on a summer evening overpowers my skepticism. What if we’re not losing fireflies after all?
Either way, the best way to proceed on a personal level is to make our gardens mini firefly preserves by doing the following:
• Avoid the use of chemicals on your property!
• Leave worms, snails, and slugs for firefly larvae to feed on.
• Turn off the lights.
• Provide nice ground cover, grasses and shrubs for them to luxuriate about in.
And on a broader scale, pay attention to and speak up on issues of: Agricultural chemicals (pesticides are designed to kill insects, after all); habitat destruction (they obviously need a place to call home); and light pollution (which interferes with their communication).
You can read more about the issues in my ode to lightning bugs here: What’s happening to the fireflies? And see Bowman’s Sun-Times story here.