Can mycorrhizal fungi indirectly affect plant-ant mutualisms?
Laird, Robert*,1, Addicott, John1, 1 Department of Biological Sciences, Calgary, Alberta, Canada ABSTRACT- Plants provide a conduit through which below- and aboveground ecological processes can interact. For example, soil-dwelling arbuscular mycorrhizal (‘AM’) fungi trade soil nutrients for carbohydrates that their host plant produces during photosynthesis. This exchange alters the host plant’s morphology and physiology, leading to a variety of positive and negative indirect effects on insect herbivores and pollinators. We tested the hypothesis that AM fungi can also indirectly affect insects involved in protection-for-food mutualisms, in which the insects (typically ants) protect their host plant from herbivory in exchange for food rewards in the form of extra-floral nectar. We manipulated the presence/absence of AM fungi in broad bean plants (Vicia faba L., Fabaceae) and found that plants with AM fungal associations produced fewer food rewards (i.e., fewer extra-floral nectaries) com
