Paracoenia calida

Wilbur Springs Shore Fly

Family: Ephydridae · Class: Insecta · Order: Diptera

Conservation status: G1 S1

The Wilbur Springs shore fly is a small dipteran insect in the family Ephydridae, known from only a single locality in California. This species belongs to the genus Paracoenia within the tribe Ephydrini. Physical characteristics of this species have not been well documented in the scientific literature, though like other shore flies, it is presumably small with the typical robust body form characteristic of the Ephydridae family. Paracoenia calida is endemic to California and appears to be restricted to Wilbur Springs in Colusa County. The species' extremely limited distribution contributes to its designation as both globally and state imperiled (G1 S1). No additional populations have been documented despite surveys in potentially suitable habitat in the region. Specific habitat requirements for the Wilbur Springs shore fly have not been thoroughly studied. As a member of the Ephydridae, this species likely inhabits areas near water sources, potentially associated with the mineral springs environment that characterizes the Wilbur Springs area. Shore flies typically develop in aquatic or semi-aquatic habitats, including alkaline or saline waters, muddy substrates, and areas with organic matter accumulation. Ecological information for Paracoenia calida remains largely undocumented. Shore flies generally undergo complete metamorphosis with aquatic or semi-aquatic larval stages. Adults are typically active during warmer months and may feed on organic matter, algae, or microorganisms. Breeding behavior, seasonal activity patterns, and specific dietary requirements for this species have not been described in available literature. The conservation status of the Wilbur Springs shore fly reflects its extremely restricted range and limited population. The species carries a G1 S1 ranking, indicating it is critically imperiled both globally and within California due to extreme rarity. According to the U.S. Fish and Wildlife Service ECOS database, this species is tracked as part of the federal species monitoring system, though it does not currently hold federal listing status under the Endangered Species Act as of December 2025. The primary conservation concerns likely include habitat modification, water management impacts, and the inherent vulnerability associated with having only a single known population. Any disturbance to the Wilbur Springs locality could potentially threaten the entire known population of this species. The limited scientific documentation of Paracoenia calida highlights the need for additional taxonomic and ecological research. Detailed studies of its life history, habitat requirements, and population status would be valuable for developing appropriate conservation strategies. Given the species' extremely restricted distribution, continued monitoring of the Wilbur Springs locality and protection of this unique habitat are essential for the persistence of this endemic California dipteran. Scientific documentation for this species remains limited. If you have additional verified information about this species' biology, distribution, or ecology, please contact us to help improve this species account.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.