Ponderous Borer
( Trichocnemis spiculatus )


2008-0808-01100147-COL01012-Trichocnemis_spiculatus[1532h02s,F,A,tree-bark]{EXD}-G.jpg

IDENTIFICATION
Identification:Trichocnemis spiculatus
(LeConte, 1851)
Common Name:Ponderous Borer
Life Stage:A

PHYLOGENY

Phylum:Arthropoda
Class:Insecta
Superorder:Holometabola
Order:Coleoptera
Suborder:Polyphaga
Family:Cerambycidae
Subfamily:Prioninae
Tribe:Callipogonini
Genus:Trichocnemis
Taxon Code:COL01012
ITIS TSN#:702741

LOCATION DETAILS
Location
The Meadow, Joaquin Miller Park, 3590 Sanborn Drive, Oakland
County:Alameda County
ECI Site#:CA01100147

RECOGNITION
Adult: Uniformly very dark brown with rectangular bodies. Thorax: Lateral margins are lined with numerous tiny spines. Antennae: Long and thin. Larvae: Full grown larvae are thick-bodied, creamy white with a reddish-brown head bearing four toothlike processes just above the mandibles.
Body Length
Adults: 42-65 mm.
Similar Taxa
California Prionus (Prionus californicus) is similar in size, but is not as dark brown as T. spiculatus. Also, the antennae in P. californicus is pectinate.
Colors
Very dark brown.

BIOLOGY
Host
Grubs are found chiefly in Ponderosa Pine and Douglas Fir, but will also attack oak, madrone, poplar, apple, cherry, walnut, chestnut and some eucalyptuses.
Active Period
Adults fly from June to September and may be attracted to lights in wooded areas of Oakland.
Development
Females lay eggs in basal crevices of dead or dying trees. Larvae excavate very large, meandering galleries, first in the sapwood then deep into the heartwood. The life cycle is presumed to require several to many years.
Importance
This insect plays an important role in fire ecology. Larvae, known to loggers as "timberworms", feed on trees that are already dead or dying. Feeding weakens tree reducing standing fuel available during fires. The mandibles of this beetleā€™s grub is said to have been the inspiration for the modern chainsaw.
Range
Western North America.

HABITAT

CREDITS
Photographer
Eddie Dunbar

REFERENCES
  • Species Trichocnemis spiculatus - Ponderous Borer. (http://bugguide.net/node/view/74268). Accessed March 12, 2016. [ IMAGES ]
  • Integrated Taxonomic Information System TSN#702741
  • Western Forest Insects


.