Q: I was wondering if you could help me out with another insect ID. I have this tree that crashed and while inspecting it found what appears to be insect holes and the insect attached. Is it possible for this insect to affect a tree?
A: This is an uncommon beetle without a nice common name. I checked with our identification expert, Gene Hall, in the entomology department on campus to be sure since I hadn’t seen one before. The scientific name of the beetle is Trimitomerus riversi and it belongs to the insect Family Pythidae — Dead Log Bark Beetles.
This species, the only one of the genus found in North America, is restricted to Southern Arizona. While adults have been collected, the larval stage and life cycle of this beetle is unknown. Larvae of other species in the Pythidae family have been collected in the subcortical of dead conifers, deciduous logs, or sapwood of rotted conifers.
There is still much to learn about the natural histories of this group so getting an identity is the best we can do for now. With upwards of 70 million insect species out there and a little over one million described, we occasionally find one that we don’t now much about. The family descriptor, dead log bark beetles, makes me think you have nothing to worry about.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to plwarren@cals.arizona.edu
