Of course, the thing that makes fireflies stand out from other insects and beetles is their ability to light up! This is a type of bioluminescence. The part of a firefly’s abdomen that lights up is known as its lantern. Within the lantern are specialized cells called photocytes, and within those cells are the chemicals that create the light of fireflies. The flashing of fireflies is created by regulating how much oxygen is released into the photocytes - when oxygen is present, the light flashes on, when oxygen is not present, there is no light.
Different types of fireflies can be identified by their flash patterns. In most species in the eastern United States, the males fly and flash a certain pattern to attract a mate. The females sit on the ground or on plants and flash a different pattern in response. Different species also prefer different habitats and tend to appear at different times of the evening or season.
In 2019 we were able to confirm that Lutherlyn is home to one of the most interesting species of firefly - Photinus carolinus! These are the rare synchronized fireflies. The males of this species flash all together for several seconds and then go dark for several seconds in unison, creating a mesmerizing pattern of synchronized flashing and darkness in the forests where they fly.
Their presence has only been confirmed in a few places in the United States. Viewing this rare spectacle of synchronized flashing has become a popular tourist attraction in Great Smoky Mountains National Park, which is home to the largest population of Photinus carolinus. In recent years, it has been confirmed that a thriving population also exists in Allegheny National Forest in northwest Pennsylvania, which has led to the PA Firefly Festival in Kelletville, PA. PAFF events have expanded from a one-night festival in one location to advocating for fireflies, expanding our knowledge of Photinus carolinus in Pennsylvania, and hosting educational events in a number of locations with confirmed populations of synchronous fireflies.
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| Photinus carolinus, photo by Peggy Butler at Camp Fossil Creek, 2021. |
A number of years ago we happened upon synchronized flashing on a night hike into the forest with campers early in the summer. We were able to confirm with organizers from PAFF that we do indeed have Photinus carolinus at Lutherlyn, and this year we hosted a PAFF Glow and Know campout event. Glow and Know events are intentionally small – registration is capped at 15 participants – and focus on education as well as viewing the synchronous fireflies in their habitat. It is not easy to see synchronized fireflies, mostly because they hang out in places that humans usually are not - they are most visible in open spaces within mature forests after 10:00 or 11:00 pm. They are best viewed, of course, in the dark, with flashlights, cell phones and cameras turned off. They are most active in our area in mid-June. While Lutherlyn is private property and cannot host drop-in visitors during summer camp season (when the synchronous fireflies are active), you can see synchronous fireflies in Allegheny National Forest, at PA Firefly Festival events, and at Smokey Mountains National Park and Congaree National Park. Or maybe, if you explore a forest near you late at night in June, you may discover that these famous fireflies are in more places than we know!
For more on PA Firefly Festival programs check out https://www.pafireflyevents.org .
While the synchronized fireflies
may be the most spectacular and rare species we have seen at Lutherlyn, there
are plenty of other fireflies around, and they all have their own distinctive
flash patterns too, as well as favored habitats and peak times. We are
fortunate at Lutherlyn to have a lot of suitable habitat for fireflies of many
different types, and therefore many spectacular fireflies to enjoy on summer
evenings! This summer keep an eye out for fireflies and their flash patterns.
