Interactions between host plants, endophytic fungi, and a phytophagous insect in an oak (Quercus grisea x Q. gambelii) hybrid zone

• Published in: Oecologia 1996-02, Vol.105 (3), p.336-342
• Main Authors: Eric S. Gaylord, Preszler, Ralph W., Boecklen, William J.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Biological taxonomies; crossbreds; ecologia; ecologie; ecology; endofitas; endophyte; endophytes; Endosymbionts; Fundamental and applied biological sciences. Psychology; Fungi; gnomonia; Gracillariidae; herbivore; Herbivores; herbivoros; hibridos; Host plants; hybride; Hybridity; hybrids; Leaves; Lepidoptera; Mortality; Phyllonorycter; Phytophagous insects; plant animal relations; Plants; Population Ecology; productos del cruzamiento; produit de croisement; Quercus gambelii; Quercus grisea; relaciones planta animal; relation plante animal; sinergismo; Synecology; synergism; synergisme; Terrestrial ecosystems
• ISSN: 0029-8549; 1432-1939
• DOI: 10.1007/BF00328736

We examined interactions between host plants, endophytic fungi, and leaf-mining moths (Phyllonorycter sp.) in an oak (Quercus grisea × Q. gambelii) hybrid zone. The community of endophytic fungi and two common endophyte species examined responded to host plant hybridization. Total fungal frequency (TFF) and frequency of Gnomonia cerastis were lowest on hosts resembling Q. grisea, and increased linearly towards those resembling Q. gambelii. In contrast, Coccochorella quercicola was most frequently isolated from Q. grisea-like hosts and decreased in frequency across hybrids towards Q. gambelii. Frequency of G. cerastis and TFF covaried with Phyllonorycter density across the hybrid zone, but direct effects of endophytes on Phyllonorycter density were not detected. Associations between endophytes and unexplained mortality of Phyllonorycter varied according to endophyte species and stage of Phyllonorycter development. In the sap-feeding stage, unexplained mortality was negatively associated with TFF and frequencies of Hormonema sp. and Preussia funiculata; whereas, in the tissue-feeding stage, unexplained Phyllonorycter mortality was positively associated with G. cerastis frequency. Three-way interactions between plant hybridization, endophytic fungi, and the insect herbivore were not significant.