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.

If you need an accessible version of this item please contact JSTOR User Support

Sycamore Aphid Numbers and Population Density: II. Some Processes

R. J. Chambers, P. W. Wellings and A. F. G. Dixon
Journal of Animal Ecology
Vol. 54, No. 2 (Jun., 1985), pp. 425-442
DOI: 10.2307/4489
Stable URL: http://www.jstor.org/stable/4489
Page Count: 18
  • Read Online (Free)
  • Download ($18.00)
  • Subscribe ($19.50)
  • Cite this Item
If you need an accessible version of this item please contact JSTOR User Support
Sycamore Aphid Numbers and Population Density: II. Some Processes
Preview not available

Abstract

(1) Laboratory populations of the sycamore aphid tend to reach an asymptotic density in the autumn, irrespective of the initial number of aphids colonizing the trees. This population behaviour is not observed in the field populations (see Wellings et al. 1985), where immigration and density-disturbing weather conditions may be important. (2) Analysis of the data from the laboratory populations identified two density-dependent processes: flight by adult first generation aphids and reduced fecundity of second generation adults as a result of crowding experience. (3) Growth and development rates of individual aphids were influenced by the nutritional value of their host plant and by crowding density. (4) Other laboratory experiments indicated that the effect of crowding was mediated through the host plant, rather than solely through direct behavioural interactions. This effect was shown to act during development and the pre-reproductive period, as well as on the reproductive rate of adults. (5) The role of these intraspecific processes in the regulation of sycamore aphid numbers is discussed.

Page Thumbnails

  • Thumbnail: Page 
425
    425
  • Thumbnail: Page 
426
    426
  • Thumbnail: Page 
427
    427
  • Thumbnail: Page 
428
    428
  • Thumbnail: Page 
429
    429
  • Thumbnail: Page 
430
    430
  • Thumbnail: Page 
431
    431
  • Thumbnail: Page 
432
    432
  • Thumbnail: Page 
433
    433
  • Thumbnail: Page 
434
    434
  • Thumbnail: Page 
435
    435
  • Thumbnail: Page 
436
    436
  • Thumbnail: Page 
437
    437
  • Thumbnail: Page 
438
    438
  • Thumbnail: Page 
439
    439
  • Thumbnail: Page 
440
    440
  • Thumbnail: Page 
441
    441
  • Thumbnail: Page 
442
    442