Stars of a sweet summer night: HCT firefly program sparkles at Cold Brook

As a magnificent twilight spread over the Robert F. Smith Cold Brook Preserve, there was great mystery in the air. Would we see fireflies? After all, that’s what we were there for: an eyeful of those glorious natural fireworks that bring you back to summers of your youth, when glowing magic was all around.

Seeing these living sparklers was also quite the festive way to get in the spirit for the 250th anniversary of the United States!

There are no guarantees in the natural world, but we hoped that luck would be on our side to spot some lightning bugs. And it sure helped to have the expert guidance of Harwich Conservation Trust (HCT) volunteer walk leader Gerry Beetham, captain of the ship for HCT’s first-ever Cold Brook Firefly Walk.

Beetham began the lightning bug quest with a quote from acclaimed naturalist and entomologist E.O. Wilson, that firmly established the importance of insects to healthy ecosystems around the world: “If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago. If insects were to vanish, the environment would collapse into chaos.”

A short, busy life

This awe-inspiring appetizer set the table for a main course of fantastic fireflies. Including this: “they’re not actually flies, they are beetles,” said Beetham, as he swung into a thorough illumination of this flying, flickering favorite.

We learned that there are about 20 to 25 species of fireflies on Cape Cod, with similar life cycles that start with eggs, then move on to a larval stage (the longest part of their life cycle), followed by a pupal stage when it develops into an adult. The story finishes with a short stint as an adult, when reproduction is the mission, and the entire saga takes one or two years, depending on the species.

So, there is some poignancy to seeing adult fireflies strutting their stuff at night. They might only spend a week or so in showoff mode before they exit the stage and their lives are over.

Romance in the air

“The ones you see in the air are the males,” said Beetham. “The females are all down on the ground. The males are trying to impress the females with their flash. And if they do, the female will flash back and they mate.” The females will lay eggs, and the next generation starts their journey.

But where were the fireflies? Our eyes were peeled as we ambled along the All Persons Trail at Cold Brook, part of the recent rewilding project at the Preserve that also restored 44 acres of wetland and a mile of stream habitat. The native plants were flourishing, and other wildlife was doing their thing, but the twinkling bugs were elusive.

Slowly, dark descended, and that’s when things changed. At first, we only saw a few fireflies, near the edge of the woods. It was good to greet our old friends, but when it comes to fireflies, you’re looking for a fiesta, not a solo act.

As we crossed a Cold Brook bridge, the big show started. Fireflies were everywhere! High in trees, low on shrubs, flying to and fro–like a natural disco where bug romance provided the lights. We all talked about days of yore, about being a kid in the summer, when fireflies fired our imagination and being outside was a wondrous thing.

How to help fireflies

We felt pretty darn lucky, especially when Beetham told us that firefly sightings have become less common in recent years, due to habitat loss and light pollution, which disrupts their flashing and reduces reproductive success.

And pesticides are a real problem. “Avoid pesticides, chemical fertilizer, turn off the lights and reduce lawn mowing,” he said. “Leave the leaves that come down in the fall. Fireflies depend on ground habitat.”

Wow, Beetham’s tips mean less yardwork and more fireflies — that’s a deal we can all get behind!

We walked back to the parking lot, buzzing about our after-dark adventure and the wonder-bugs that graciously appeared on cue. There are only a few true elements to recapturing that kid-summer feeling: lemonade, a good swim, fire-toasted marshmallows, walking barefoot in the grass and perhaps, most importantly, seeing fireflies in the night sky.

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