PARENT SESSION
Tuesday, August 8, 8:00-11:30 am
COS 20 - Food webs I: trophic interactions
Mississippi, Mezzanine Level, Cook Convention Center
Presiders: D Gruner

Drooling over fungal endophytes: the effect of ungulate saliva on the growth of Epichloë festucae.

Tanentzap, Andrew^*,1, Vicari, Mark¹, ¹ York University, Toronto, ON, Canada

ABSTRACT- As producers of toxic alkaloids that deter herbivory, fungal endophytes modify plant-herbivore interactions. However, studies from endophyte-infected Festuca rubra suggest that foliar endophytes may or may not reduce grazing pressure. All attempts to address this question have focused on grass-endophyte or grass-herbivore interactions, ignoring direct links between the endophyte and herbivore. Evidence of antifungal properties of herbivore saliva in other systems implies that evolutionary pressures may select for herbivores that are able to mitigate the effect of endophyte-produced toxic alkaloids. Here we tested the effect of moose (Alces alces) and European reindeer (Rangifer tarandus tarandus) saliva on in vitro hyphal elongation of Epichloë festucae isolated from 3 genotypes of F. rubra. We placed filter-sterilized distilled water, saliva from moose, or saliva from reindeer, on the edge of E. festucae colonies emerging from F. rubra tillers onto potato-dextrose agar in the dark at room temperature. Moose saliva significantly lowered hyphal growth rate and colony diameter during the first 120 hours after application when compared to the water and reindeer treatments. We propose that diverging responses between saliva treatments may be related to differences in (1) herbivore migration; (2) territoriality; and (3) feeding strategy.

Key words: multitrophic interactions, fungi--endophytic, plant-herbivore ecology