Soldier determination in Pheidole bicarinata: Effect of methoprene on caste and size within castes

Diana E. Wheeler, H. Frederik Nijhout

Research output: Contribution to journalArticlepeer-review

80 Scopus citations


Topical application of methoprene to final-instar larvae of the ant Pheidole bicarinata can induce soldier development. Soldier induction takes place if methoprene levels are above a soldier-determining threshold during a critical period of juvenile hormone-sensitivity that occurs during about days 4-6 of the final instar. Furthermore, the amount of exogenous methoprene applied affects the timing of metamorphosis and the adult size in both the minor worker and soldier castes. When larvae that receive methoprene treatment become minor workers these are always larger than acetone-treated controls. In larvae that become soldiers, growth and timing of metamorphosis vary with the dose of methoprene, but in a more complex way. A high dose of methoprene produces a metamorphic delay and large soldiers. However, the lowest effective dose for soldier induction produces early metamorphosis and small adults. On the basis of these results, we have expanded our model of a mechanism by which juvenile hormone could control determination of worker castes in Pheidole bicarinata.

Original languageEnglish (US)
Pages (from-to)847-854
Number of pages8
JournalJournal of Insect Physiology
Issue number11
StatePublished - 1983


  • Caste
  • Pheidole bicarinata
  • ant
  • methoprene
  • soldier

ASJC Scopus subject areas

  • Physiology
  • Insect Science


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