Observation: Photinus pyralis
Primary Observer:
Christine Tysor
Event Date:
2025-07-15
Status:
Unverified
Survey
Site Name:
Undisclosed
Province/State:
Virginia
Event Date:
2025-07-15
Time of Day:
Night-Time
Start Time:
21:16
End Time:
21:30
Number of Observers:
1
Primary Observer:
Christine Tysor
Additional Observers:
N/A
target_species_genus:
photinus
target_species_species:
pyralis
Location and Habitat
Location Accuracy (meters):
0-25
Habitat Type:
Woodland/Forest - Trees dominant, and in the over-story
Habitat Type Notes:
Cedar, oak, Eastern redbuds prominent trees with taller grasses in the under story.
Elevation (meters):
581
Area Searched (hectares):
.001
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): No
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:
2-10
genus:
photinus
Species:
pyralis
Observation Notes:
Flashing pattern was approximately 1-1.5 seconds and a greenish light
Specimen Voucher Number:
Flash Behavior
First Flash Time:
21:16
Last Flash Time:
21:30
First Flash Temp (F):
75 degrees
Last Flash Temp (F):
75 degrees
Flashes in Pattern:
1
Flash Color:
Green
Flash Pattern Period:
10 seconds
Flash Duration:
1-1.5 seconds
Flash Interval:
3 seconds
Male Height Zone:
Moderate (3-8 ft), High (over 8 ft)
Flash Location:
Close to tree lines
Male Flash Behavior:
flash with a few seconds pause between. Multiple flashes would occur in a very short period of time.
Female Flash Behavior:
None
1 thought on “Observation: Photinus pyralis”
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Thank you for submitting this firefly observation! I am intrigued about what species it might have been. It is hard to know for certain without photos of the firefly, but a few things suggest to me that this might have been a species other than Photinus pyralis. Photinus pyralis typically has a flash pattern interval of 5-7 seconds, and these flashes are usually yellow and pretty low to the ground, in contrast to the green flashes at greater heights and intervals of ~3 seconds that you observed. Photuris fireflies, which generally have greenish flashes, would be expected in this region at this time of year.
A note about flash pattern terminology:
“Flash pattern period” refers to the number of seconds between the start of a flash pattern and the start of the next repetition of that flash pattern. For example, Photinus pyralis typically has a flash pattern period of 5-7 seconds.
“Flash duration” is how long each flash lasts. Usually this is too fast to measure accurately, but you can estimate whether it is more or less than 0.5 seconds, you can enter “not recorded,” or you can do a verbal description (such as “very brief”).
“Flash interval” refers to the time between the end of one flash and the beginning of the next. In species with single flash patterns and short flash durations, this is basically the same as “flash pattern period,” just a little shorter.