Common Name
Sky island firefly
Scientific Name
Photuris falli
Recent Synonyms
Photuris flavicollis, Photuris brunnipennis var. falli
Adult Male Size
8.4-11.5 mm
Diet
Unknown, but likely snails, slugs, and other soft-bodied invertebrates
Firefly Atlas Category
Focal species
The sky island firefly is known from the Davis Mountains and adjacent mountain ranges of West Texas and appears to occur in an adjunct population in southern Arizona. Little is known about the population size and trend, or habitats and ecology of this range-restricted flashing firefly. Threats to this species include habitat disturbance due to development for oil and gas extraction, light pollution, and drought.
Conservation
Reason(s) For Firefly Atlas Focal Species Designation
Reliably identifiable, Suspected population loss
Status
IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species is an inventory of the global conservation status and extinction risk of biological species, maintained collectively by scientists worldwide.Vulnerable (VU)
NatureServe
The NatureServe conservation status ranks use a standardized methodology to assess the extinction risk of species, with a focus on the US and Canada. State wildlife agencies and natural heritage programs use these ranks to prioritize species for conservation actions.Globally critically imperiled to vulnerable (G1G3) Not yet assessed in Texas (SNR)
Species of Greatest Conservation Need Lists
Species of Greatest Conservation Need (SGCN) are lists of species included in State Wildlife Action Plans, identifying animals and plants that need the most conservation attention and resources at the state and region level.None
US Endangered Species Act
The Endangered Species Act is a United States law that provides legal protections to species that are officially listed as endangered or threatened by the US Fish and Wildlife Service.N/A
Threats
The major threat to this species is habitat disturbance due to development for oil and gas extraction, light pollution, and drought. Surveys are needed to better understand this species’ distribution. Its distinctive morphology and long breeding season may help with species ID, which is notoriously difficult for other Photuris species.
Location
Distribution
USA
Arizona, Texas
Details
The sky island firefly has been documented from Brewster and Jeff Davis Counties in the Davis Mountains and surrounding mountain ranges of West Texas. It is possible this species is found elsewhere in the remote mountain ranges of West Texas, occurring in isolated pockets where small spring complexes flow into dry creek beds. Museum specimens from the Florida State Collection of Arthropods also indicate this species is found near Cochise Stronghold in the Dragoon Mountains of southern Arizona, although survey efforts in 2023 and 2024 were unsuccessful in finding extant populations.
Habitat
The habitat associations for this species are not well understood, although it seems to occur in isolated pockets in areas where small spring complexes flow into dry creek beds. However, it has also been reported from dry habitats where surface water appears to be lacking, including mesquite and bristle cone pine forests and north-facing slopes with Ponderosa pines and bunch grasses.
Behavior
Activity Period
The phenology of the adult flight season is not well understood, although individuals have been reported from early May through early August. Their flight behavior may be influenced by seasonal monsoon activity, with wetter years resulting in more sightings.
Flash Pattern
Males emit a continuous single green flash approximately 0.2 seconds in duration, repeated every 0.7 seconds. Female flash pattern is unknown but is likely a single green flash response.
Sources
Keller, O. 2023. Personal communication between Oliver Keller (Florida State Collection of Arthropods) and Candace Fallon and Richard Joyce (Xerces Society for Invertebrate Conservation). 10 July 2023.
Pfeiffer, B. & Walker, A. 2021. Photuris flavicollis. The IUCN Red List of Threatened Species 2021: e.T164045916A166771548. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T164045916A166771548.en. Accessed on 11 September 2025.
Walker, A. 2024. Guide to Fireflies of the Southwest. New Mexico BioPark Society, Albuquerque, NM. Available at https://www.fireflyatlas.org/learn/firefly-publications. Accessed on 11 September 2025.
