Journal of Comparative Physiology A

, Volume 198, Issue 3, pp 219–227

Serotonin modulates worker responsiveness to trail pheromone in the ant Pheidole dentata

  • Mario L. Muscedere
  • Natalie Johnson
  • Brendan C. Gillis
  • J. Frances Kamhi
  • James F. A. Traniello
Original Paper

DOI: 10.1007/s00359-011-0701-2

Cite this article as:
Muscedere, M.L., Johnson, N., Gillis, B.C. et al. J Comp Physiol A (2012) 198: 219. doi:10.1007/s00359-011-0701-2


As social insect workers mature, outside-nest tasks associated with foraging and defense are typically performed at higher frequencies. Foraging in ants is often a pheromonally mediated collective action performed by mature workers; age-dependent differences in olfactory response thresholds may therefore proximately regulate task repertoire development. In the ant Pheidole dentata, foraging activity increases with chronological age in minor workers, and is chemically controlled. The onset of foraging in minor workers is accompanied by marked neuroanatomical and neurochemical changes, including synaptic remodeling in olfactory regions of the brain, proliferation of serotonergic neurons, and increased brain titers of monoamines, notably serotonin. We examined the linkage of serotonin and olfactory responsiveness by assaying trail-following performance in mature P. dentata minor workers with normal serotonin levels, or serotonin levels experimentally lowered by oral administration of the serotonin synthesis inhibitor α-methyltryptophan (AMTP). By assessing responsiveness to standardized pheromone trails, we demonstrate that trail-following behaviors are significantly reduced in serotonin-depleted workers. AMTP-treated individuals were less likely to initiate trail following, and oriented along pheromone trails for significantly shorter distances than untreated, similar-age workers. These results demonstrate for the first time that serotonin modulates olfactory processes and/or motor functions associated with cooperative foraging in ants.


Neuromodulation Behavioral development Serotonin Foraging Pheromonal communication 



5-Hydroxytryptamine (serotonin)


Age class




Analysis of variance




High-performance liquid chromatography with electrochemical detection



Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Mario L. Muscedere
    • 1
    • 2
  • Natalie Johnson
    • 1
    • 3
  • Brendan C. Gillis
    • 1
    • 4
  • J. Frances Kamhi
    • 1
  • James F. A. Traniello
    • 1
  1. 1.Department of BiologyBoston UniversityBostonUSA
  2. 2.Program in Neuroscience, Boston UniversityBostonUSA
  3. 3.Department of Molecular, Cell and Developmental BiologyUniversity of ColoradoBoulderUSA
  4. 4.Biology DepartmentNortheastern UniversityBostonUSA

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