The effects of natural enemies, competition, and host plant water availability on an aphid population

Published

Journal Article

I used a factorial experiment repeated in two years to assess the relative effects of natural enemy attack, interspecific competition, and water availability to the host plant, and of interactions among these factors, on the population dynamics of the aphid Aphis varians feeding on fireweed (Epilobium angustifolium). The impact of a suite of coccinellid and syrphid predators emerged as the predominant factor affecting the success of aphid colonies: colonies protected from natural enemies grew in size at a rate of ten percent per day, were only one tenth as likely to go extinct, and produced over ten times more dispersing alates. In contrast, I found only minor effects of removing flea beetles, the most abundant herbivore with which A. varians colonies cohabit fireweed stems, and of supplementing water availability to fireweed host plants, in spite of a significant effect of watering frequency on aphid growth in the green-house. There was no evidence of significant two- or three-way interactions among factors. Hence, despite the potential complexity of the food web in which it is embedded, the dynamics of A. varians appears to be driven predominantly by a single factor, i.e. interactions with natural enemies. © 1992 Springer-Verlag.

Full Text

Duke Authors

Cited Authors

  • Morris, WF

Published Date

  • June 1, 1992

Published In

Volume / Issue

  • 90 / 3

Start / End Page

  • 359 - 365

Electronic International Standard Serial Number (EISSN)

  • 1432-1939

International Standard Serial Number (ISSN)

  • 0029-8549

Digital Object Identifier (DOI)

  • 10.1007/BF00317692

Citation Source

  • Scopus