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Sting, Carry and Stock: How Corpse Availability Can Regulate De-Centralized Task Allocation in a Ponerine Ant Colony.

Schmickl T, Karsai I - PLoS ONE (2014)

Bottom Line: The common stomach is able to establish and to keep stabilized an effective mix of workforce to exploit the prey population and to transport food into the nest.The model is compared to previously published models that followed a different modeling approach.Based on our model analysis we also suggest a series of experiments for which our model gives plausible predictions.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, Karl-Franzens-University, Graz, Austria.

ABSTRACT
We develop a model to produce plausible patterns of task partitioning in the ponerine ant Ectatomma ruidum based on the availability of living prey and prey corpses. The model is based on the organizational capabilities of a "common stomach" through which the colony utilizes the availability of a natural (food) substance as a major communication channel to regulate the income and expenditure of the very same substance. This communication channel has also a central role in regulating task partitioning of collective hunting behavior in a supply&demand-driven manner. Our model shows that task partitioning of the collective hunting behavior in E. ruidum can be explained by regulation due to a common stomach system. The saturation of the common stomach provides accessible information to individual ants so that they can adjust their hunting behavior accordingly by engaging in or by abandoning from stinging or transporting tasks. The common stomach is able to establish and to keep stabilized an effective mix of workforce to exploit the prey population and to transport food into the nest. This system is also able to react to external perturbations in a de-centralized homeostatic way, such as to changes in the prey density or to accumulation of food in the nest. In case of stable conditions the system develops towards an equilibrium concerning colony size and prey density. Our model shows that organization of work through a common stomach system can allow Ectatomma ruidum to collectively forage for food in a robust, reactive and reliable way. The model is compared to previously published models that followed a different modeling approach. Based on our model analysis we also suggest a series of experiments for which our model gives plausible predictions. These predictions are used to formulate a set of testable hypotheses that should be investigated empirically in future experimentation.

No MeSH data available.


Related in: MedlinePlus

Predicted response of the ant colony to a varying density of prey items with constant total prey number (left figure) and to a varying number of prey items at a constant prey density (right figure).In both cases we measured the maximum number of stingers (solid line) and of transporters (broken lines). In both cases we used the default parameters listed in Table 1, except nColony = 240, tmax = 120. The varied parameter is indicated on the x-axis of both figures. Left figure: P(0) = 400; right figure: P(0) is varied between 80 and 380 prey items across the runs.
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pone-0114611-g006: Predicted response of the ant colony to a varying density of prey items with constant total prey number (left figure) and to a varying number of prey items at a constant prey density (right figure).In both cases we measured the maximum number of stingers (solid line) and of transporters (broken lines). In both cases we used the default parameters listed in Table 1, except nColony = 240, tmax = 120. The varied parameter is indicated on the x-axis of both figures. Left figure: P(0) = 400; right figure: P(0) is varied between 80 and 380 prey items across the runs.

Mentions: One of the important objectives of our model (objective 2) was to test if a “common stomach”-based model would provide comparable prediction to data reported by Schatz et al. [27]. Thus we ran our model with the same densities and numbers of prey as it is described by Schatz et al. [27]. We report the maximum peak of stingers in each setting, because such experimental settings can produce a pulsed response of the colony (Fig. 5). Our model predicted a very similar picture compared to the findings of Schatz et al. [27]: The number of ants engaged in stinging and transporting is significantly modulated by prey density, but it did not change significantly with varying number of initial prey number (Fig. 6.).


Sting, Carry and Stock: How Corpse Availability Can Regulate De-Centralized Task Allocation in a Ponerine Ant Colony.

Schmickl T, Karsai I - PLoS ONE (2014)

Predicted response of the ant colony to a varying density of prey items with constant total prey number (left figure) and to a varying number of prey items at a constant prey density (right figure).In both cases we measured the maximum number of stingers (solid line) and of transporters (broken lines). In both cases we used the default parameters listed in Table 1, except nColony = 240, tmax = 120. The varied parameter is indicated on the x-axis of both figures. Left figure: P(0) = 400; right figure: P(0) is varied between 80 and 380 prey items across the runs.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4262436&req=5

pone-0114611-g006: Predicted response of the ant colony to a varying density of prey items with constant total prey number (left figure) and to a varying number of prey items at a constant prey density (right figure).In both cases we measured the maximum number of stingers (solid line) and of transporters (broken lines). In both cases we used the default parameters listed in Table 1, except nColony = 240, tmax = 120. The varied parameter is indicated on the x-axis of both figures. Left figure: P(0) = 400; right figure: P(0) is varied between 80 and 380 prey items across the runs.
Mentions: One of the important objectives of our model (objective 2) was to test if a “common stomach”-based model would provide comparable prediction to data reported by Schatz et al. [27]. Thus we ran our model with the same densities and numbers of prey as it is described by Schatz et al. [27]. We report the maximum peak of stingers in each setting, because such experimental settings can produce a pulsed response of the colony (Fig. 5). Our model predicted a very similar picture compared to the findings of Schatz et al. [27]: The number of ants engaged in stinging and transporting is significantly modulated by prey density, but it did not change significantly with varying number of initial prey number (Fig. 6.).

Bottom Line: The common stomach is able to establish and to keep stabilized an effective mix of workforce to exploit the prey population and to transport food into the nest.The model is compared to previously published models that followed a different modeling approach.Based on our model analysis we also suggest a series of experiments for which our model gives plausible predictions.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, Karl-Franzens-University, Graz, Austria.

ABSTRACT
We develop a model to produce plausible patterns of task partitioning in the ponerine ant Ectatomma ruidum based on the availability of living prey and prey corpses. The model is based on the organizational capabilities of a "common stomach" through which the colony utilizes the availability of a natural (food) substance as a major communication channel to regulate the income and expenditure of the very same substance. This communication channel has also a central role in regulating task partitioning of collective hunting behavior in a supply&demand-driven manner. Our model shows that task partitioning of the collective hunting behavior in E. ruidum can be explained by regulation due to a common stomach system. The saturation of the common stomach provides accessible information to individual ants so that they can adjust their hunting behavior accordingly by engaging in or by abandoning from stinging or transporting tasks. The common stomach is able to establish and to keep stabilized an effective mix of workforce to exploit the prey population and to transport food into the nest. This system is also able to react to external perturbations in a de-centralized homeostatic way, such as to changes in the prey density or to accumulation of food in the nest. In case of stable conditions the system develops towards an equilibrium concerning colony size and prey density. Our model shows that organization of work through a common stomach system can allow Ectatomma ruidum to collectively forage for food in a robust, reactive and reliable way. The model is compared to previously published models that followed a different modeling approach. Based on our model analysis we also suggest a series of experiments for which our model gives plausible predictions. These predictions are used to formulate a set of testable hypotheses that should be investigated empirically in future experimentation.

No MeSH data available.


Related in: MedlinePlus