A command chemical triggers an innate behavior by sequential activation of multiple peptidergic ensembles

Curr Biol. 2006 Jul 25;16(14):1395-407. doi: 10.1016/j.cub.2006.06.027.


Background: At the end of each molt, insects shed their old cuticle by performing the ecdysis sequence, an innate behavior consisting of three steps: pre-ecdysis, ecdysis, and postecdysis. Blood-borne ecdysis-triggering hormone (ETH) activates the behavioral sequence through direct actions on the central nervous system.

Results: To elucidate neural substrates underlying the ecdysis sequence, we identified neurons expressing ETH receptors (ETHRs) in Drosophila. Distinct ensembles of ETHR neurons express numerous neuropeptides including kinin, FMRFamides, eclosion hormone (EH), crustacean cardioactive peptide (CCAP), myoinhibitory peptides (MIP), and bursicon. Real-time imaging of intracellular calcium dynamics revealed sequential activation of these ensembles after ETH action. Specifically, FMRFamide neurons are activated during pre-ecdysis; EH, CCAP, and CCAP/MIP neurons are active prior to and during ecdysis; and activity of CCAP/MIP/bursicon neurons coincides with postecdysis. Targeted ablation of specific ETHR ensembles produces behavioral deficits consistent with their proposed roles in the behavioral sequence.

Conclusions: Our findings offer novel insights into how a command chemical orchestrates an innate behavior by stepwise recruitment of central peptidergic ensembles.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Behavior, Animal*
  • Calcium / metabolism
  • Central Nervous System / cytology
  • Central Nervous System / metabolism
  • Central Nervous System / physiology
  • Drosophila / anatomy & histology
  • Drosophila / growth & development*
  • FMRFamide / metabolism
  • Insect Hormones / metabolism
  • Insect Hormones / pharmacology
  • Insect Hormones / physiology*
  • Molecular Sequence Data
  • Molting / physiology*
  • Neurons / cytology
  • Neurons / metabolism
  • Neuropeptides / metabolism*
  • Phenotype
  • Receptors, Peptide / genetics
  • Receptors, Peptide / metabolism
  • Signal Transduction*


  • Insect Hormones
  • Neuropeptides
  • Receptors, Peptide
  • ecdysis-triggering hormone receptor, Drosophila
  • ecdysis-triggering hormone, Drosophila
  • FMRFamide
  • Calcium

Associated data

  • GENBANK/AY220741
  • GENBANK/AY220742