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Observation: Pyractomena dispersa
Primary Observer:
Carl Manthey
Event Date:
2025-05-18
Status:
Unreviewed
Survey
Site Name:
Great Marsh, Elverson, PA
Province/State:
Pennsylvania
Event Date:
2025-05-18
Time of Day:
Night-Time
Start Time:
20:00
End Time:
21:45
Number of Observers:
9
Primary Observer:
Carl Manthey
Additional Observers:
Myrna Villanueva, Karen Owens, Bernard Brown, Kathy Varaday, Jackie Ahlborn, Diana Cormack, Christa Tyner, Tripp Tyner
Target Species Genus:
unknown
Target Species Species:
unknown
Location and Habitat
Location Accuracy (meters):
500-1000
Habitat Type:
Open Freshwater Wetland - Wetland Bog, fen, freshwater marsh
Habitat Type Notes:
Wet meadow with grasses, sedges, and native (mostly) perennials
Elevation (meters):
150 - 200
Area Searched (hectares):
12
Artificial Light Sources
Vehicles: No
Street Lights: No
Buildings: No
Street Lights: No
Buildings: No
Artificial Light Types
Sky Glow (diffuse illumination in the sky): Yes
Light Trespass (light cast on surfaces beyond its intended target): No
Glare (bright light causing visual discomfort): No
Light Trespass (light cast on surfaces beyond its intended target): No
Glare (bright light causing visual discomfort): No
Artificial Light Notes:
Light pollution was generally mild/minimal at locations where fireflies were observed. There was a small amount of sky glow. Nominal light trespass from distant house/bldgs was observed from the Marsh Creek bridge on Moore's RD.
Observation
Observation Type:
Flashing
Number Observed:
50+
Genus:
Pyractomena
Species:
dispersa
Observation Notes:
Specimen Voucher Number:
Flash Behavior
First Flash Time:
20:49
Last Flash Time:
21:45
First Flash Temp (F):
65
Last Flash Temp (F):
65
Flashes in Pattern:
1
Flash Color:
Yellow
Flash Pattern Period:
4 to 5
Flash Duration:
~0.5
Flash Interval:
3 to 4
Male Height Zone:
Low (0-3 ft), Moderate (3-8 ft)
Flash Location:
In and low over wet (squishy) meadows. One third appear to be flashing while stationary in the vegetation and two thirds are flashing while flying low.
Fireflies flashing low over marsh and wet meadows were observed on all three routes by the three teams. The male shown in the photograph was from the marsh/wet meadow adjacent to the Turnpike service area.
Male Flash Behavior:
Of the ones that are stationary in the vegetation, some are showing single flashes while others are showing double or triple flashes. The male in the photograph was in the vegetation. Whether in the vegetation or in the air, the flashes are bright and the flash intervals are variable with some showing single flashes with quite long dark intervals. Some of the flashes look like large falling sparks from a campfire. There was a divergence in opinion about flash color. Some perceived the flash to be a rich color, possibly orange. Some said the flashes were yellow and others said the flashes were white.
