Dissemination of the conifer seed fungus Caloscyphafulgens by small mammals

Abstract

Field studies showed that the seed-pathogenic fungus Caloscyphafulgens (Pers.) Boudier was present in squirrel caches in 25% of the white spruce, Piceaglauca (Moench) Voss, stands in an area near Prince George, B.C. and in duff in 17 and 8% of the lodgepole pine, Pinuscontorta Dougl., clear-cuts there and at Williams Lake, respectively. In the laboratory, deer mice (Peromyscusmaniculatus Wagner), chipmunks (Eutamiastownsendii Bachman), and Douglas squirrels (Tamiasciurusdouglasii Bachman) consumed C. fulgens infested seeds of Douglas-fir, Pseudotsugamenziesii (Mirb.) Franco, lodgepole pine, and white spruce as readily as noninfested seeds. Squirrels also ate C. fulgens ascocarps and passed intact ascospores, but these were not observed to germinate. Red squirrels, T. hudsonicus Erxleben, moved, and ate seeds from, both infested and noninfested Douglas-fir cones in the field. It is proposed that C. fulgens is disseminated by squirrels, and perhaps other rodents, and that the fungus may preserve seeds in caches thereby ensuring squirrel food supplies between cone crops. Caloscyphafulgens may also prevent seed germination in direct seeding trials.