Consumption of sound and decayed ponderosa pine and Douglas-fir by Reticulitermes spp. (Isoptera: Rhinotermitidae) from Northern California

Survival, amount of wood consumed, and the feeding rate of workers of western subterranean termites, Reticulitermes spp., were assessed on sapwood blocks of ponderosa pine, Finns ponderosa Dougl. ex Laws, and Douglas-fir, Pseudotsuga menziesii (Mirb.) France, that were sound or decayed by 1 of 2 brown-rot fungi, Gloeophylum trabeum (Fr.) Murr, or Postia placenta (Fr.) M. Lars & Lomb. Groups of 200 workers were confined separately on combinations of each wood and fungal species for 28 d. Mean survivorship of 2 colonies was 89.5 and 96.1%, and were not significantly different, whereas 1 of these suffered significantly greater mortality when fed wood of either species decayed by G. trabeum. Groups of workers consumed an average of 293 mg or 25.5% of wood during the test period. The amount and percentage of wood consumed by termites was significantly Greater when decayed by either fungus; however, 1 colony consumed significantly more wood of both species when decayed by C. trabeum. When corrected for mortality over the length of the test, feeding (milligrams wood per worker per 28 d) was not significantly different between colonies or wood species. Wood of either species was consumed at a significantly greater rate if decayed by G. trabeum (1.77 mg per termite per 28 d) than by P. placenta (1.55 mg per termite per 28 d); wood decayed by either fungus was consumed at a significantly greater rate than nondecayed wood (1.25 mg per termite per 28 d).