Photos from the WFIWC Archives:
Mexico
Figure A. The "Wilted Pine," Pinus lumholtzii, Durango, Mexico (M. Furniss photo)
Figure B. Gallery of Pityoborus rubentis with brood adults extending "larval cradles." The gallerey characteristics and associated ambrosia fungus ally Pityoborus with xylomycetophagus scolytids although some of their features are intermediate to phloeophagus species. (M. Furniss photo)
Figure C. Pubescent mycangium (above antenna) of a female. The asperites on the pronotum serve as rakes to move spores from the cradle walls into the mycangia. (M. Furniss photo)
Figure D. SEM photo of X-section through pubescent area (P. secundus, Chihuahua) showing round ambrosia spores scattered among setae. They are released in new galleries by brushing of the setae against the tunnel wall. (M. Furniss photo)
Continuing in Mexico: March 24, 1974. On a very primitive road 34 miles south of Durango City toward La Flor, we encountered an amazing sight. There along the road was a wilted pine tree! Or, so it seemed. Then, we began to see others of all ages and soon realized that their drooping needles was a species trait. Later, I learned that the pine was Pinus lumholtzii. I was amazed to find scolytid galleries in dead limbs that were intermediate between bark beetles and ambrosia beetles. They deeply etched the sapwood and had cradle-like structures at right angle to the gallery. I noted that the pronotum of females had setal patches on each side. They were identified as Pityoborus rubentis by S.L. Wood. Some years later, I was examining ascospores in pits on Ips beetles and decided to see if these setal patches held spores. They did, indeed, and the spores were those of an ambrosia fungus. A reviewer of the subsequent manuscript (Furniss et al. 1987) objected to calling these fungus repositories "mycangia" (not fitting the classical description of the time). However, Lekh Batra, USDA Mycology Lab, Beltsville, MD, sided with us and that publication widened the accepted definition. I had no trouble applying the term to pits on Ips typographus and I. pini in publishing subsequent studies. -- Malcolm M. Furniss
Reference
Furniss, M. M., J. Y. Woo, M. A. Deyrup, and T. H. Atkinson. 1987. Prothoracic mycangium on pine-infesting Pityoborus spp. (Coleoptera: Scolytidae). Ann. Entomol. Soc. Am. 80:692-696.
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