Pleocoma hirticollis

Schaufuss, 1870

rain beetle

Species Guides

1

Pleocoma hirticollis is a of rain beetle in the Pleocomidae, a group of scarab beetles to western North America. The species is active during autumn and winter rains, emerging only when soil is saturated. Three are recognized: P. h. hirticollis, P. h. reflexa, and P. h. vandykei. Like other Pleocomidae, are sexually dimorphic and do not feed.

Pronunciation

How to pronounce Pleocoma hirticollis: /ˌpliːəˈkoʊmə hɜːrˈtɪkoʊlɪs/

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Identification

Pleocoma hirticollis can be distinguished from other Pleocoma by details of male genitalia and antennal structure. Males have with elongated clubs; females are flightless with forelegs adapted for digging. The specific epithet 'hirticollis' refers to the hairy neck region. differ in male paramere shape and geographic distribution.

Distribution

Western North America. Specific range details are limited in available sources, but the occurs in California and adjacent regions based on distributions (P. h. vandykei described from California).

Seasonality

Active during autumn and winter rainfall periods; triggered by saturated soil conditions. are not observed during dry seasons.

Life Cycle

Complete with larvae feeding on roots. Larval development extends over multiple years. are non-feeding and short-lived, existing solely for .

Behavior

emerge only during rain events, hence the 'rain beetles.' Males fly to locate flightless females, which remain near burrows. Activity is strictly and rain-dependent.

Ecological Role

Larvae are root-feeders, potentially influencing plant structure in their . serve as prey for vertebrate during their brief periods.

Human Relevance

Of minor economic concern; larvae may feed on roots of agricultural plants or native vegetation. Occasionally attracted to lights during . Not a significant pest.

Similar Taxa

  • Pleocoma rufescensOverlapping range in California; distinguished by male genitalia and antennal proportions
  • Pleocoma sonomaeNorthern California distribution; differs in paramere and size

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