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Observation: Photuris
Primary Observer:
Brandie Dunn
Event Date:
2025-08-02
Status:
Verified
Survey
Site Name:
BF
Province/State:
Illinois
Event Date:
2025-08-02
Time of Day:
Night-Time
Start Time:
20:15
End Time:
22:00
Number of Observers:
4
Primary Observer:
Brandie Dunn
Additional Observers:
Tom Simpson, Michael Dunn, Ders Anderson
Target Species Genus:
unknown
Target Species Species:
unknown
Location and Habitat
Location Accuracy (meters):
0-25
Habitat Type:
Open Freshwater Wetland - Wetland Bog, fen, freshwater marsh
Habitat Type Notes:
Jewelweed, Joe Pye weed, cattails, Bog/fen bordering oak woodland that increases in elevation as you enter woodland to north. We followed trail into woodland to the west towards opening to meadowy area, passing a seep along the way. The oaks and tall tree canopy block moonlight for the most part.
Elevation (meters):
820
Area Searched (hectares):
.16
Artificial Light Sources
Vehicles: Yes
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:
Observation
Observation Type:
Flashing
Number Observed:
2-10
Genus:
Photuris
Species:
unknown
Observation Notes:
14 mm. Single flashes exhibited along the pathway from the ground level.
Specimen Voucher Number:
Flash Behavior
First Flash Time:
21:02
Last Flash Time:
22:00
First Flash Temp (F):
68.9
Last Flash Temp (F):
64
Flashes in Pattern:
1
Flash Color:
Green
Flash Pattern Period:
1
Flash Duration:
.5
Flash Interval:
1
Male Height Zone:
Low (0-3 ft)
Flash Location:
On the ground
Male Flash Behavior:
Female Flash Behavior:
Suspected female, attempting to attract males/prey?
1 thought on “Observation: Photuris”
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Thanks for submitting this firefly observation! You are correct that this is a female Photuris, which makes species ID challenging, as the flash behavior won’t align with the male courtship flash pattern, which is what we generally use for ID purposes.
I’m honestly not sure what species this could be, as the Photuris in Illinois haven’t been studied very closely. The 14 mm length and dark colored hind coxae (both helpful cluses) could point toward Photuris versicolor or Photuris tremulans, though early August would be quite late in the season for P. tremulans.