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Coleoptera of Great Smoky Mountains National Park Species Pages

Family Nitidulidae

            Subfamily Nitidulinae

 Pocadius helvolus Erichson

The hairy puffball beetle

Description and Taxonomy

Description. Adult length 3.5-4.5mm. Members of the genus Pocadius can be distinguished from those of other nitidulid genera by the characteristic pattern of pubescence on the dorsal body surface, particularly on the elytra. Rows of erect, longer setae are interspersed with rows of shorter, closely appressed setae. The body color, particularly the extent of the orange-brown subbasal area of the elytra is variable. When encountered in their puffball hosts, adults appear as small, moving balls of spores, as pictured below. 

Mature larval length 6.0-7.5mm. Body gray to tan, integument dry and leathery in texture. Dorsally with elongate, stiff setae, these emerging from six transverse scoli on 2nd-3rd thoracic and abdominal segments 1-8. Urogomphi short, with small, tuberculate pregomphi.

 This genus was recently revised for the world by A. R. Cline as a Ph.D. dissertation (Cline 2005) and publication as a monograph is imminent (dissertation download available). When publication of the new names is accomplished, it will include 46 species from throughout most temperate (except south temperate) and tropical regions of the world, with four occurring in the U.S. Pocadius helvolus is the only species that occurs in the eastern U.S.

Life History

The species of the genus as a whole are considered to be specialists of various puffball mushrooms (Lycoperdaceae), though occurrence records exist for other kinds of fungi. Pocadius helvolus specimens are most commonly encountered inside specimens of the common puffballs of the genus Lycoperdon (click here for example image). Adults presumably enter the fresh fruiting body, where they feed and deposit eggs. The larvae mature as the puffball does. Mature larvae can be found in specimens of puffballs that are dry and sporulating. Please think of the Pocadius before you stomp your next puffball!

Distribution

Pocadius helvolus occurs in most eastern states and extends into the Pacific Northwest and southwest  into central Mexico. The single record from the vacinity of Purchase Knob is totally misleading and an artifact of inadequate collecting.

Conservation Concerns

The species is not known to be under threat.

Adult of P. helvolus as seen in mature spore body of puffball mushroom.

Exposed larvae of P. helvolus in puffball.

Dried puffball showing characteristic entry/exit holes caused by P. helvolus. Diameter ~3cm.

 

Locality records in GSMNP.

Acknowledgements

Development of these pages was supported by grants from Discover Life in America and the National Science Foundation (DEB-0516311).

References

Cline, A. R. 2005. Revision of Pocadius (Coleoptera: Nitidulidae). Ph.D. Dissertaion, Louisiana State University, Baton Rouge, LA, 383 pp. http://etd.lsu.edu/docs/available/etd-11042005-122348/unrestricted/Cline_dis.pdf accessed 21 September 2006.

Posted 21 Sep. 2006, C. E. Carlton, Louisiana State Arthropod Museum.

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