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.

Experimental Evidence for Effective and Altruistic Colony Defence against Natural Predators by Soldiers of the Gall-Forming Aphid Pemphigus spyrothecae (Hemiptera: Pemphigidae)

W. A. Foster
Behavioral Ecology and Sociobiology
Vol. 27, No. 6 (1990), pp. 421-430
Published by: Springer
Stable URL: http://www.jstor.org/stable/4600501
Page Count: 10
  • Download ($43.95)
  • Cite this Item
Experimental Evidence for Effective and Altruistic Colony Defence against Natural Predators by Soldiers of the Gall-Forming Aphid Pemphigus spyrothecae (Hemiptera: Pemphigidae)
Preview not available

Abstract

The thick-legged first instar soldiers of the gall-forming aphid Pemphigus spyrothecae Pass. are able to protect the aphids in the gall from being eaten by a range of insect predators. In artificial galls, the soldier aphids were able to kill first instar ladybirds Adalia bipunctata (L.) (Coleoptera: Coccinellidae), early third instar hoverfly larvae Eupeodes (Metasyrphus) corollae (Fab.) (Diptera: Syrphidae), and first-third instar Anthocoris nemoralis (Fab.) (Hemiptera: Cimicidae). Almost all the aphids that attacked the predators were themselves killed. The soldiers were also able to kill predators introduced into natural galls. Experiments were devised in which individuals of Anthocoris minki, which is the most important insect predator of the gall generations of Pemphigus at the study site, were free to enter and leave the gall: the soldiers were effective both in preventing the predator's access to the gall and in killing those predators that did manage to get in. In galls with experimentally manipulated numbers of soldiers and non-soldiers, it was clearly shown that it is the soldiers alone that kill the predators (Anthocoris minki and 1st instar Adalia bipunctata) (see Table 3). Even though many soldiers may die during these encounters, the selective advantage of killing the predators is high, since observations show that individual A. minki can pass through more than one instar inside a gall and kill all the aphids therein. The aphids were not observed to attack conspecific aphids from other galls or the cohabiting aphid Chaitophorus leucomelas Koch. The primary role of the soldier caste is therefore the defence of the aphid colony against predators.

Page Thumbnails

  • Thumbnail: Page 
[421]
    [421]
  • Thumbnail: Page 
422
    422
  • Thumbnail: Page 
423
    423
  • Thumbnail: Page 
424
    424
  • Thumbnail: Page 
425
    425
  • Thumbnail: Page 
426
    426
  • Thumbnail: Page 
427
    427
  • Thumbnail: Page 
428
    428
  • Thumbnail: Page 
429
    429
  • Thumbnail: Page 
430
    430