Pleocoma oregonensis

Differs from other Pleocoma species by geographic distribution; P. oregonensis is restricted to Oregon and Utah, whereas most congeners occur in California. Adult males have distinctive lamellate antennae with elongated clubs. Females are flightless with reduced wings and enlarged fossorial legs adapted for burrowing.

Found in montane and foothill regions of the Pacific Northwest. Associated with coniferous forest soils where larvae develop.

Endemic to the Nearctic region; recorded from Oregon and Utah, United States.

Adults emerge during autumn rains, typically October to November. Activity is strongly correlated with precipitation events.

Complete metamorphosis with prolonged larval development. Larvae are soil-dwelling and feed on decaying organic matter and roots. Adults do not feed; their mouthparts are reduced or non-functional. Males fly during rainy evenings to locate flightless females at burrow entrances.

Males exhibit crepuscular and nocturnal flight activity triggered by rainfall. Females remain in burrows near the soil surface, emitting pheromones to attract males. Both sexes are incapable of feeding as adults.

Larvae contribute to soil nutrient cycling through burrowing and processing of organic material. Adults serve as a seasonal food source for vertebrate predators including birds and small mammals.

• Pleocoma hirticollisOverlaps in Oregon range; distinguished by male genitalic morphology and subtle differences in antennal club structure
• Pleocoma marquaiAnother Oregon endemic; requires examination of male parameres for definitive separation

• rain beetle
• fossorial
• autumn emergence
• flightless female
• soil-dwelling larvae

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life