Observation: Photinus pyralis
Primary Observer:
Christopher Stompanato
Event Date:
2025-06-29
Status:
Unverified
Survey
Site Name:
Naperville Stomps
Province/State:
Illinois
Event Date:
2025-06-29
Time of Day:
Night-Time
Start Time:
20:20
End Time:
20:40
Number of Observers:
1
Primary Observer:
Christopher Stompanato
Additional Observers:
NA
target_species_genus:
unknown
target_species_species:
unknown
Location and Habitat
Location Accuracy (meters):
0-25
Habitat Type:
Developed - Sub/urban areas; parks/gardens
Habitat Type Notes:
Standard suburban neighborhood with numerous trees and shrubs.
Elevation (meters):
0
Area Searched (hectares):
3
Artificial Light Sources
Vehicles: No
Street Lights: No
Buildings: Yes
Street Lights: No
Buildings: Yes
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:
Observation
Observation Type:
With Flash Data
Number Observed:
50+
genus:
photinus
Species:
pyralis
Observation Notes:
Certain front yards had amazing numbers of lightning bugs to the point it looked like a fireworks show with an estimated 40 bugs lighting up at nearly the same time. Other yards had nearly no activity but overall across a square block, a tremendous number of active lightning bugs were observed.
Specimen Voucher Number:
Flash Behavior
First Flash Time:
20:20
Last Flash Time:
20:40
First Flash Temp (F):
80
Last Flash Temp (F):
80
Flashes in Pattern:
3
Flash Color:
Yellow
Flash Pattern Period:
3
Flash Duration:
1
Flash Interval:
3
Male Height Zone:
Low (0-3 ft)
Flash Location:
Neighborhood lawns.
Male Flash Behavior:
At times upwards of 40 flashes at nearly the same time. An amazing display.
Female Flash Behavior:
1 thought on “Observation: Photinus pyralis”
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Based on the early evening display time, the urban/suburban setting, and the low display height, I am tentatively identifying this as big dipper (Photinus pyralis), which is the dominant species of flashing firefly in the Chicago area.
Did the fireflies dip and then rise up as they were flashing (creating a J-shape)? That, along with photos of the fireflies in hand, would help to confirm.