Occam's razor cuts both ways: endophytes, resource allocation, herbivory, and mutualism: a reply to Rudgers et al.

Fungal endophytes and their grass hosts have attracted growing research interest as systems in which to examine the ecological and evolutionary consequences of maternally inherited symbioses. The lion’s share of research for these endophytic symbioses has been focused on Neotyphodium endophytes in three introduced agronomic grasses (but especially one, tall fescue; see Faeth and Saikkonen 2007; fig. 7.1 in Cheplick and Faeth 2009), and much of the conventional wisdom about endophyte‐host interactions has been developed from these agronomic grass systems. However, accumulating studies from wild grasses suggest important species‐specific differences between host grass–endophyte associations and therefore challenge concepts based on a few agronomic grass systems. My long‐term study (Faeth 2009) of how asexual Neotyphodium endophytes affect resource allocation and herbivore loads in a wild grass, Arizona fescue (Festuca arizonica), is one of these, and Rudgers et al. (2010) challenge both my methods and my interpretation.