Observation: Pyractomena dispersa
Primary Observer:
Rachel Irvin
Event Date:
2025-06-11
Status:
Unreviewed
Survey
Site Name:
Grimes Pond
Province/State:
Utah
Event Date:
2025-06-11
Time of Day:
Night-Time
Start Time:
22:25
End Time:
23:15
Number of Observers:
3
Primary Observer:
Rachel Irvin
Additional Observers:
Iris McCulloch and Adam Sovinsky.
Target Species Genus:
Pyractomena
Target Species Species:
dispersa
Location and Habitat
Location Accuracy (meters):
0-25
Habitat Type:
Riparian - Areas Along lake or stream
Habitat Type Notes:
The area was adjacent to a walking path, with grassy meadows all around. A river ran through and the water flow seemed to be managed by irrigation meters. Along the water were plants like saltbush, erigeron, milkweed, some sort of succulent, yellow flower (possibly marigold). Plants where fireflies were observed included thistles, grasses, clovers, amaranth, and cottonwood trees.
Elevation (meters):
1384
Area Searched (hectares):
0.37
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:
This area was quite secluded, with the only light occurring at the beginning of the walking path, which did not reach the survey location.
Observation
Observation Type:
Flashing
Number Observed:
11-50
Genus:
Pyractomena
Species:
dispersa
Observation Notes:
We observed orange colored and light blue colored flashes. We caught a specimen of each (photos taken at 10:58 PM are specimen 1, photos taken at 11:07 PM are specimen 2), and they appeared to be the same species. 2 grid cells (referencing the grid paper used in our specimen photos) represent approximately 1 centimeter. This would make the fireflies body (not including head) approximately 1 cm long.
Specimen Voucher Number:
Flash Behavior
First Flash Time:
22:25
Last Flash Time:
23:10
First Flash Temp (F):
81
Last Flash Temp (F):
81
Flashes in Pattern:
3
Flash Color:
Blue
Flash Pattern Period:
1.25
Flash Duration:
0.13
Flash Interval:
0.25
Male Height Zone:
Low (0-3 ft)
Flash Location:
Flashes first observed in low growing bushes (likely females). After those initial flashes, we observed males meandering through the open, grassy meadow at low heights. The highest flash only reached about 5 ft above ground.
Male Flash Behavior:
Flashes appeared to be light blue or orange. Flashes were quick, sometimes with a pause before a single flash.
Female Flash Behavior:
When we first approached the site, we witnessed what we assumed were female flashes. The flashes lit up two or three bushes. After those quick flashes, we didn't see any more.
