Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Positive Predator-Predator Interactions: Enhanced Predation Rates and Synergistic Suppression of Aphid Populations

John E. Losey and Robert F. Denno
Ecology
Vol. 79, No. 6 (Sep., 1998), pp. 2143-2152
Published by: Wiley
DOI: 10.2307/176717
Stable URL: http://www.jstor.org/stable/176717
Page Count: 10
  • Download ($42.00)
  • Subscribe ($19.50)
  • Cite this Item
Positive Predator-Predator Interactions: Enhanced Predation Rates and Synergistic Suppression of Aphid Populations
Preview not available

Abstract

Interactions among predators can a have substantial effect on the total impact of the predator complex. We investigated the interaction between foliar-foraging (Coccinella septempunctata) and ground-foraging (Harpalus pennsylvanicus) predators of the pea aphid (Acyrthosiphon pisum) in a series of laboratory and field experiments. The intensity and direction of the interaction were determined by comparing the combined and individual impacts of both predators. In a laboratory mesocosm, the combined predation rate of both predators was nearly double the sum of their individual predation rates. The mechanism for the interaction was the aphid "dropping" behavior elicited by C. septempunctata, which rendered the aphids susceptible to predation by H. pennsylvanicus on the ground. The strength of the synergistic interaction increased with increasing prey density. The interaction between the predators was also demonstrated in both open and closed field cages where the combined impact of the two predators on aphid population growth was significantly greater than the sum of their individual impacts. These results indicate that the importance of ground-foraging predators in agroecosystems may need to be reevaluated and that positive interactions between predators must be considered in models predicting the impact of multiple predator complexes.

Page Thumbnails

  • Thumbnail: Page 
2143
    2143
  • Thumbnail: Page 
2144
    2144
  • Thumbnail: Page 
2145
    2145
  • Thumbnail: Page 
2146
    2146
  • Thumbnail: Page 
2147
    2147
  • Thumbnail: Page 
2148
    2148
  • Thumbnail: Page 
2149
    2149
  • Thumbnail: Page 
2150
    2150
  • Thumbnail: Page 
2151
    2151
  • Thumbnail: Page 
2152
    2152