Eleodes marginata

Family: Tenebrionidae · Class: Insecta · Order: Coleoptera

Eleodes marginata is a darkling beetle belonging to the family Tenebrionidae, subfamily Blaptinae. This species is classified within the subgenus Discogenia and is part of the desert stink beetle group (Eleodes). Adults measure approximately 15 mm (0.6 inches) in length, displaying the characteristic robust, elongated body form typical of Eleodes beetles. The species exhibits a dark, typically black coloration with a somewhat flattened appearance and prominent marginal ridges that give the species its name. Eleodes marginata occurs along the California coast, with documented populations in Marin County. Specimens have been recorded from Point Reyes National Seashore, indicating the species' presence in coastal environments (BugGuide.Net). The species appears to have a limited distribution within California, though comprehensive range surveys have not been well documented in available literature. The species inhabits coastal forest environments, particularly bishop pine and Douglas fir forests. Ground-dwelling by nature, E. marginata is typically found on the forest floor among leaf litter and organic debris. The coastal location suggests the species may be adapted to the moderate temperatures and higher humidity associated with maritime influence. Elevation preferences and specific microhabitat requirements have not been thoroughly documented. As a member of the Tenebrionidae, E. marginata is primarily detritivorous, feeding on decaying organic matter, fungi, and plant material. Like other Eleodes species, adults are likely flightless, with fused wing covers (elytra) that serve a protective function rather than facilitating flight. When disturbed, the species may exhibit the characteristic defensive behavior of raising its abdomen and releasing chemical secretions, a trait common among darkling beetles that gives them the common name "stink beetles." Reproductive biology and seasonal activity patterns have not been specifically documented for this species. Eleodes marginata does not appear on federal or state endangered species lists as of December 2025, and no specific conservation status has been assigned. However, the species' apparently limited coastal distribution in California could make it vulnerable to habitat loss from coastal development, recreational activities, and climate change impacts. The coastal forest ecosystems where this species occurs face ongoing pressures from human activities and altered fire regimes. Point Reyes National Seashore provides some habitat protection, though comprehensive population assessments have not been conducted. Scientific documentation for this species remains limited beyond basic taxonomic information and scattered observation records. The information presented here synthesizes available sources from taxonomic databases and community observations. Detailed ecological studies examining population dynamics, habitat requirements, and conservation needs would enhance understanding of this species' status in California's coastal ecosystems.

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