Juveniles and the elderly defend, the middle-aged escape: Division of labour in a social aphid

Keigo Uematsu, Masakazu Shimada, Harunobu Shibao

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


In colonies of social insects, non-random spatial positioning within the colonies may reflect division of labour and improve colony efficiency. Here, we describe a novel defence system in the colony of a gall-forming social aphid, Quadrartus yoshinomiyai (Nipponaphidini), where young and old defensive aphids move towards the dangerous area typically associated with a higher risk of predation, whereas the middle-aged reproductive individuals move away. Younger nymphs and post-reproductive adults of Q. yoshinomiyai concurrently defend against predators that intrude after their galls open. In natural open galls, both types of defenders were preferentially located around the open area vulnerable to invasion by predators, whereas reproductive individuals remained in the safer areas. In addition, when a hole was artificially made in closed galls, these morphs located themselves in similar spatial positions to the natural open galls within 12 hours. The defensive system led by oldest and youngest individuals may reflect the possibility of future reproduction for these insects, thereby optimizing colony efficiency in a seasonally changing environment, according to the reproductive values of colony members.

Original languageEnglish
Article number20121053
JournalBiology letters
Issue number2
Publication statusPublished - 2013 Apr 23
Externally publishedYes


  • Division of labour
  • Reproductive value
  • Social aphids
  • Spatial organization

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • General Agricultural and Biological Sciences


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