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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.


Labeled entrance chamber.A photograph of the entrance chamber of colony N_4 covered with the window used during filming. The tunnels to the deeper nest are labeled, as is the trail of returning and outgoing foragers.
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pone.0141971.g002: Labeled entrance chamber.A photograph of the entrance chamber of colony N_4 covered with the window used during filming. The tunnels to the deeper nest are labeled, as is the trail of returning and outgoing foragers.

Mentions: To observe interactions inside the entrance chamber, we excavated the soil above the entrance chamber, as in Pinter-Wollman et al. [13]. We positioned a rectangular piece of plywood (23cm x 28cm) such that one of the short edges of the wood was directly over the nest entrance. The rest of the wood was positioned over the entrance tunnel and entrance chamber. We drew an outline around the wood, removed the wood, and dug out approximately 4cm of soil from the rectangular area for all films made in 2012 and approximately 9cm of soil for films made in 2013. The area exposed in 2012 corresponds to the area inside the nest entrance described as the 'vestibule' in Pinter-Wollman et al. [13]. The area we exposed in the 2013 observations described here included more of the entrance chamber than in 2012. Here we refer to both as the 'entrance chamber'. We covered the area with the wood overnight so that the ants would acclimate to their new nest ceiling. Each morning between 6am and 11am, we removed the wood and covered the excavated area with a rectangular glass sheet (23cm x 28cm) for filming (Fig 2). Previous studies show that the incoming light does not disturb the ants [13].


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)

Labeled entrance chamber.A photograph of the entrance chamber of colony N_4 covered with the window used during filming. The tunnels to the deeper nest are labeled, as is the trail of returning and outgoing foragers.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0141971.g002: Labeled entrance chamber.A photograph of the entrance chamber of colony N_4 covered with the window used during filming. The tunnels to the deeper nest are labeled, as is the trail of returning and outgoing foragers.
Mentions: To observe interactions inside the entrance chamber, we excavated the soil above the entrance chamber, as in Pinter-Wollman et al. [13]. We positioned a rectangular piece of plywood (23cm x 28cm) such that one of the short edges of the wood was directly over the nest entrance. The rest of the wood was positioned over the entrance tunnel and entrance chamber. We drew an outline around the wood, removed the wood, and dug out approximately 4cm of soil from the rectangular area for all films made in 2012 and approximately 9cm of soil for films made in 2013. The area exposed in 2012 corresponds to the area inside the nest entrance described as the 'vestibule' in Pinter-Wollman et al. [13]. The area we exposed in the 2013 observations described here included more of the entrance chamber than in 2012. Here we refer to both as the 'entrance chamber'. We covered the area with the wood overnight so that the ants would acclimate to their new nest ceiling. Each morning between 6am and 11am, we removed the wood and covered the excavated area with a rectangular glass sheet (23cm x 28cm) for filming (Fig 2). Previous studies show that the incoming light does not disturb the ants [13].

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.