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Interactions Increase Forager Availability and Activity in Harvester Ants.

Pless E, Queirolo J, Pinter-Wollman N, Crow S, Allen K, Mathur MB, Gordon DM - PLoS ONE (2015)

Bottom Line: Here we compare the interaction rate experienced by foragers that left the nest and ants that did not.We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging.Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Stanford University, Stanford, California, United States of America.

ABSTRACT
Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant foragers interact in a chamber just inside the nest entrance, here called the 'entrance chamber'. Previous studies of the activation of foragers in red harvester ants show that an outgoing forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return. An increase in the rate of forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of forager return leads to more available foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning foragers regulate both the activation of waiting foragers and the number of foragers available to be activated.

No MeSH data available.


Comparison of activity distribution by colony.Each bar shows the mean proportion of ascending ants that foraged (black), did nest maintenance (white), or ascended into the nest entrance but then descended back into the deeper nest without leaving the nest to forage (grey), over the course of three days. Error bars show standard errors of the mean.
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pone.0141971.g003: Comparison of activity distribution by colony.Each bar shows the mean proportion of ascending ants that foraged (black), did nest maintenance (white), or ascended into the nest entrance but then descended back into the deeper nest without leaving the nest to forage (grey), over the course of three days. Error bars show standard errors of the mean.

Mentions: To determine the sample size of outgoing foragers, we considered the possibility that if the proportion of foragers were extremely different in the three colonies observed, a given sample size would not be equally representative in all three colonies. We found that the proportions foraging in the three colonies were not significantly different (ANOVA, F2,6 = 3.854; p = 0.08) (Fig 3) (S1 Dataset). Therefore, we decided to measure interaction rates in the same number of foragers and descending ants in all three colonies, rather than choose different sample sizes for each colony.


Interactions Increase Forager Availability and Activity in Harvester Ants.

Pless E, Queirolo J, Pinter-Wollman N, Crow S, Allen K, Mathur MB, Gordon DM - PLoS ONE (2015)

Comparison of activity distribution by colony.Each bar shows the mean proportion of ascending ants that foraged (black), did nest maintenance (white), or ascended into the nest entrance but then descended back into the deeper nest without leaving the nest to forage (grey), over the course of three days. Error bars show standard errors of the mean.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4635008&req=5

pone.0141971.g003: Comparison of activity distribution by colony.Each bar shows the mean proportion of ascending ants that foraged (black), did nest maintenance (white), or ascended into the nest entrance but then descended back into the deeper nest without leaving the nest to forage (grey), over the course of three days. Error bars show standard errors of the mean.
Mentions: To determine the sample size of outgoing foragers, we considered the possibility that if the proportion of foragers were extremely different in the three colonies observed, a given sample size would not be equally representative in all three colonies. We found that the proportions foraging in the three colonies were not significantly different (ANOVA, F2,6 = 3.854; p = 0.08) (Fig 3) (S1 Dataset). Therefore, we decided to measure interaction rates in the same number of foragers and descending ants in all three colonies, rather than choose different sample sizes for each colony.

Bottom Line: Here we compare the interaction rate experienced by foragers that left the nest and ants that did not.We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging.Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Stanford University, Stanford, California, United States of America.

ABSTRACT
Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant foragers interact in a chamber just inside the nest entrance, here called the 'entrance chamber'. Previous studies of the activation of foragers in red harvester ants show that an outgoing forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return. An increase in the rate of forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of forager return leads to more available foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning foragers regulate both the activation of waiting foragers and the number of foragers available to be activated.

No MeSH data available.