Misidentified Longicorn



Balsam Fir Sawyer
Location:  St. Louis County near Cromwell, Minnesota
August 19, 2010 8:44 pm
Hello! I’ve found what I believe to be a Balsam Fir Sawyer on our wooded land in St. Louis County in northern Minnesota. I haven’t been able to find much information about this insect and wonder if you could tell me bout it.
Thank you very much for any help you can provide.
Lynne Schoenborn


Hi Lynne,
We looked up the Balsam Fir Sawyer,
Monochamus marmorator, on BugGuide and we found this cited information: Larvae of the balsam fir sawyer, Monochamus marmorator Kby. (Coleoptera, Cerambycidae), contain midgut digestive enzymes active against hemicellulose and cellulose. Cellulases from larvae fed on balsam fir wood infected with the fungus, Trichoderma harzianum Rifai (Deuteromycetes, Moniliales, Moniliaceae), were found to be identical to those of the cellulase complex produced by this fungus when compared using chromatography, electrophoresis, and isofocusing. When larvae are maintained on a fungusfree diet, their midgut fluids lack cellulolytic activity, and they are unable to digest cellulose. Cellulolytic capacity can be restored by feeding the larvae wood permeated by fungi. We conclude that the enzymes which enable M. marmorator larvae to digest cellulose are not produced by the larvae. Instead, the larvae acquire the capacity to digest cellulose by ingesting active fungal cellulases while feeding in fungus-infected wood.”  reference: http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=7058239 We would love to know why it is on Invasive.org because there is no information regarding its native region.  Maybe mardikavana knows something about the Balsam Fir Sawyer.

More Questions
August 26, 2010
Thank you very much for the information.  Does this quoted article mean that the larvae only feed on decaying wood infected with fungus?  Are eggs laid in healthy trees or only dead and decaying wood?  Will they damage healthy trees?

Hi Lynne,
Sadly we are unable to answer your questions as we are not scientists.  We have found what information we were able to uncover on the internet.  We would suggest that you provide a comment on our posting of your letter so you will be notified in the future if any experts can supply additional information.

Update:  September 16, 2021
After identifying a Balsam Fir Sawyer, we realized this Longicorn is misidentified and we need to search for its identity.

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