Service Project Highlight: Great Marsh Firefly Survey
During the spring and summer of 2025, a group of curious and adventurous community scientists set out to answer a simple but fascinating question: how many species of fireflies call the Great Marsh in Chester County, Pennsylvania home?
Through a series of surveys, one conducted during the day and five at night between April and August, the group documented an impressive diversity of fireflies using both flash patterns and physical characteristics for identification.
In total, at least eight species were observed:
- Winter Firefly (Photinus corruscus)
- Marsh Flicker Firefly (Pyractomena dispersa)
- Big Dipper Firefly (Photinus pyralis)
- Yellow-Bellied Firefly (Photinus scintillans)
- Little Grey Firefly (Photinus marginellus)
- Double Cousin Firefly (Photinus consanguineus)
- Ignited Firefly (Photinus ignitus)
- An undetermined species in the genus Photuris
Firefly activity peaked in June, with especially memorable displays around June 21, when their numbers, and their glow, were at their most spectacular. By mid-July, populations began to decline rapidly, and by early August, sightings were nearly gone for the season.
Interestingly, observers also recorded several unique flash patterns in June that could not be matched to known species. Despite efforts to identify them, the fireflies responsible evaded capture suggesting that even more species may be present but undocumented.
