Subject: Tale of two beetles
Location: Southern California, USA
May 20, 2015 2:45 pm
Hello Bugman!
I recently pulled the included two beetles from my Lindgren beetle trap. In our area here in southern California we’ve had large numbers of Pine trees in the area killed off by some type of pest. My trap is about 40 feet from several pines of various types. The trap has a generic methanol lure and one specific to western pine beetle.
I’d like to find out if the two beetles (image attached) are pests or just native harmless beetles. The one brown beetle is about 2/3 the size of a June bug (may be a small one) though their season is still about 4 weeks away normally.
The black beetle I’ve never seen before and it’s about 0.5 inches in length.
About 20 miles from my location the polyphagous shot hole borer has also been located.
Any help in Identifying these beetles would be greatly appreciated.
Signature: Eric

Engraver Beetle, we believe

Horned Powder-Post Beetle

Dear Eric,
We believe, but we are not certain, that this is an Engraver Beetle in the genus
Ips, based on an image of a False Five Spined Ips in “Insects of the Los Angeles Basin” by Charles Hogue, where it states:  “The adults of this species are very small (1/4 in., or 3 mm, long) and dark brown.  The prothorax is large and partly conceals the back of the head; the wing covers are finely haired and have linear series of punctures’ the antennae are clubbed.  The species develops under the bark of pines — in our area, primarily Monterey Pine.  Usually only unhealthy or cut trees are attacked, but healthy trees are sometimes infested.  The larvae make fine tunnels through the growth layer beneath the bark, and these tunnels may connect, girdling and killing the tree.”  BugGuide has a single dorsal shot of this species, but other members of the genus pictured on BugGuide have a similar profile.  The University of California Integrated Pest Management page includes the genus Ips in the table of Bark Beetles common in Southern California landscapes.  We will try to seek opinions from Eric Eaton and Arthur Evans.  Your other beetle looks like a May Beetle, commonly called a June Bug.

Hello Daniel,
Thank you very much for the quick reply.  Time to do some more research on the little beetle.
Thanks again.  I measured the beetle in question and he is 11mm long.  So almost 3 times the length of the Ips Engraver beetle.
So perhaps he is something a little different.  Or a giant 😛

Arthur Evans provides a correction
This is a bostrichid beetle, not a bark beetle. Where is it from? Size? Any other details might help to narrow down its identity.

Ed. Note:  Our response to Arthur Evans was:  “It is from Southern California and it is about .5 inch long” and we are now awaiting further information on this Horned Powder-Post Beetle in the family Bostrichidae where, according to BugGuide:  “Most species attack wood, either living, or in some cases, dead, including seasoned lumber. A few are associated with woody fungi or stored grain.”

Location: Southern California

2 Responses to Horned Powder-Post Beetle

  1. We cut down a eucalyptus tree last year. We are keeping the wood to burn in our fire place. We just noticed small bored holes in many of the cut pieces. The is a very fine sawdust under the bark. We saw small black beetle looking insect that looks like the horned powder beetle. We have not seen them alive, only a few dead ones. Do you think it is safe to burn the wood? thank you. William

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