TY - JOUR
T1 - Serotonin modulates worker responsiveness to trail pheromone in the ant Pheidole dentata
AU - Muscedere, Mario L.
AU - Johnson, Natalie
AU - Gillis, Brendan C.
AU - Kamhi, J. Frances
AU - Traniello, James F A
PY - 2012/3
Y1 - 2012/3
N2 - 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 diVerences 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.
AB - 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 diVerences 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.
KW - Behavioral development
KW - Foraging
KW - Neuromodulation
KW - Pheromonal communication
KW - Serotonin
UR - http://www.scopus.com/inward/record.url?scp=84857455218&partnerID=8YFLogxK
U2 - 10.1007/s00359-011-0701-2
DO - 10.1007/s00359-011-0701-2
M3 - Article
C2 - 22134381
AN - SCOPUS:84857455218
SN - 0340-7594
VL - 198
SP - 219
EP - 227
JO - Journal of Comparative Physiology A
JF - Journal of Comparative Physiology A
IS - 3
ER -