PARENT SESSION
Organized Oral Session 3: Mutualists as parasites: How mutualistic are mutualists, and why?
Organizer(s): JR Powell, BE Wolfe, and JN Klironomos
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 511a, Level 5, Palais des congrès de Montréal

Understanding the role of different trophic levels in generating variability in the strength of an ant-membracid mutualism.

Billick, Ian ^*,1, Reithel, Jennifer, Tonkel, Kirk², Brown, Ryan , Relyea, Matthew³, ¹ Rocky Mountain Biological Laboratory, Gothic, CO² Truman State University, Kirksville, MO³ Adams State College, Alamosa, CO

ABSTRACT- Recent discussions of conditional mutualisms have suggested that variability in the effect of a mutualist upon its partner can make maintenance of a mutualism difficult. We determined that while the positive effects of ants on membracids varied from year to year, there was not significant spatial variation on the order of 10 kilometers. On a smaller scale, host plant species, the species of tending ant, and the presence of predators all affected the strength of the effect of ants upon membracids. However, experimental evidence suggests that on an ecological time scale this membracid species does not assume a cost to participating in the mutualism. We argue that the lack of a cost to participating in the mutualism is more important to understanding the maintenance of the mutualism than the extent to which the effect of the ants on the membracids varies in space and time.

Key words: membracids, ants, mutualisms