1. Computational and Systems Biology
  2. Ecology

Individual crop loads provide local control for collective food intake in ant colonies

  1. Efrat Esther Greenwald
  2. Lior Baltiansky
  3. Ofer Feinerman  Is a corresponding author
  1. Weizmann Institute of Science, Israel
https://doi.org/10.7554/eLife.31730
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  1. Efrat Esther Greenwald
  2. Lior Baltiansky
  3. Ofer Feinerman
(2018)
Individual crop loads provide local control for collective food intake in ant colonies
eLife 7:e31730.
https://doi.org/10.7554/eLife.31730
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Abstract

Nutritional regulation by ants emerges from a distributed process: food is collected by a small fraction of workers, stored within the crops of individuals, and spreads via local ant-to-ant interactions. The precise individual-level underpinnings of this collective regulation have remained unclear mainly due to difficulties in measuring food within ants' crops. Here we image fluorescent liquid food in individually tagged Camponotus sanctus ants, and track the real-time food flow from foragers to their gradually satiating colonies. We show how the feedback between colony satiation level and food inflow is mediated by individual crop loads; specifically, the crop loads of recipient ants control food flow rates, while those of foragers regulate the frequency of foraging-trips. Interestingly, these effects do not rise from pure physical limitations of crop capacity. Our findings suggest that the emergence of food intake regulation does not require individual foragers to assess the global state of the colony.

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Author details

  1. Efrat Esther Greenwald

    Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3614-8915

  2. Lior Baltiansky

    Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.

  3. Ofer Feinerman

    Department of Physics of Complex Systems, Weizmann Institute of Science, Rehobot, Israel
    For correspondence
    ofer.feinerman@weizmann.ac.il
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-4145-0238

Funding

Israel Science Foundation (833/15)

  • Ofer Feinerman

European Research Council (648032)

  • Ofer Feinerman

The Estate of Rachmiel Ramon Bloch

  • Ofer Feinerman

The Clore Foundation

  • Ofer Feinerman

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

© 2018, Greenwald et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Efrat Esther Greenwald
  2. Lior Baltiansky
  3. Ofer Feinerman
(2018)
Individual crop loads provide local control for collective food intake in ant colonies
eLife 7:e31730.
https://doi.org/10.7554/eLife.31730

Share this article

https://doi.org/10.7554/eLife.31730

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Further reading

    1. Computational and Systems Biology
    2. Ecology

    Emergent regulation of ant foraging frequency through a computationally inexpensive forager movement rule

    Lior Baltiansky, Guy Frankel, Ofer Feinerman
    Research Advance

    Ant colonies regulate foraging in response to their collective hunger, yet the mechanism behind this distributed regulation remains unclear. Previously, by imaging food flow within ant colonies we showed that the frequency of foraging events declines linearly with colony satiation (Greenwald et al., 2018). Our analysis implied that as a forager distributes food in the nest, two factors affect her decision to exit for another foraging trip: her current food load and its rate of change. Sensing these variables can be attributed to the forager’s individual cognitive ability. Here, new analyses of the foragers’ trajectories within the nest imply a different way to achieve the observed regulation. Instead of an explicit decision to exit, foragers merely tend toward the depth of the nest when their food load is high and toward the nest exit when it is low. Thus, the colony shapes the forager’s trajectory by controlling her unloading rate, while she senses only her current food load. Using an agent-based model and mathematical analysis, we show that this simple mechanism robustly yields emergent regulation of foraging frequency. These findings demonstrate how the embedding of individuals in physical space can reduce their cognitive demands without compromising their computational role in the group.