Summary: Ecology, 89(8), 2008, pp. 2187­2196
Ó 2008 by the Ecological Society of America
COEXISTENCE OF THREE SPECIALIST APHIDS
ON COMMON MILKWEED, ASCLEPIAS SYRIACA
R. A. SMITH,1
K. A. MOONEY,1,2
AND A. A. AGRAWAL
1,3
1
Department of Ecology and Evolutionary Biology, Corson Hall, Cornell University, Ithaca, New York 14853
2
Department of Ecology and Evolutionary Biology, Steinhaus Hall, University of California, Irvine, California 92697 USA
Abstract. Coexistence of host-specific herbivores on plants is believed to be governed by
interspecific interactions, but few empirical studies have systematically unraveled these
dynamics. We investigated the role of several factors in promoting coexistence among the
aphids Aphis nerii, Aphis asclepiadis, and Myzocallis asclepiadis that all specialize on common
milkweed (Asclepias syriaca). Competitive exclusion is thought to occur when interspecific
competition is stronger than intraspecific competition. Consequently, we investigated whether
predators, mutualists, or resource quality affected the strength of intra- vs. interspecific
competition among aphids in factorial manipulations of competition with exposure to

Source: Agrawal, Anurag - Department of Ecology and Evolutionary Biology & Entomollogy, Cornell University
Mooney, Kailen A. - Department of Ecology and Evolutionary Biology, University of California, Irvine

Collections: Environmental Sciences and Ecology