Observation: Photinus pyralis

Observation: Photinus pyralis

Primary Observer:

Christine Tysor

Event Date:

2025-07-15

Status:

Unverified

Survey

Site Name:

Ellett Valley

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

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

Artificial Light Notes:

 

Observation

Observation Type:

Flashing

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”

  1. 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.

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