Bottom-Up Effects of Plant Genotype on Aphids, Ants, and Predators

Theory predicts that bottom-up ecological forces can affect community dynamics, but whether this extends to the effects of heritable plant variation on tritrophic communities is poorly understood. In a field experiment, I contrasted the effects of plant genotype (28 genotypes; 1064 plants), aphid de...nsity, and the presence/absence of mutualistic ants in affecting the per capita population growth of a specialist aphid herbivore, as well as the effects of plant genotype on the third trophic level. Plant genotype strongly affected aphid population growth rate, explaining 29% of the total variation in growth rate, whereas aphid density and ant—aphid interactions explained substantially less variation (<2%) in aphid population growth rate. Plant genotype also had direct and indirect effects on the third trophic level, affecting the abundance of aphid-tending ants and the richness of predators. Multiple regression identified several heritable plant traits that explained 49% of the variation in aphid growth rate and 30% of the variation in ant abundance among plant genotypes. These bottom-up effects of plant genotype on tritrophic interactions were independent of the effects of either initial aphid density or the presence/absence of mutualistic ants. This study shows that plant genotyp Ausführliche Beschreibung Beschreibung ausblenden

1. Person:	Johnson, Marc T. J.
Quelle:	in Ecology : a publication of the Ecological Society of America Vol. 89, No. 1 (2008), p. 145-154 Weitere Artikel
Format:	Online-Artikel
Sprache:	English
Veröffentlicht:	2008
Beschreibung:	Online-Ressource
Schlagworte:	research-article ant—aphid mutualism Aphis oestlundi community genetics extended phenotype genetic variation Oenothera biennis plant—insect ecology top-down tritrophic interactions trophic cascade
Online Zugang:	Volltext
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Anmerkung:	Copyright: Copyright 2008 Ecological Society of America