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Gordon DM. Collective behavior in relation with changing environments: Dynamics, modularity, and agency. Evol Dev 2023; 25:430-438. [PMID: 37190859 DOI: 10.1111/ede.12439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 03/10/2023] [Accepted: 04/27/2023] [Indexed: 05/17/2023]
Abstract
Collective behavior operates without central control, using local interactions among participants to adjust to changing conditions. Many natural systems operate collectively, and by specifying what objectives are met by the system, the idea of agency helps to describe how collective behavior is embedded in the conditions it deals with. Ant colonies function collectively, and the enormous diversity of more than 15K species of ants, in different habitats, provides opportunities to look for general ecological patterns in how collective behavior operates. The foraging behavior of harvester ants in the desert regulates activity to manage water loss, while the trail networks of turtle ants in the canopy tropical forest respond to rapidly changing resources and vegetation. These examples illustrate some broad correspondences in natural systems between the dynamics of collective behavior and the dynamics of the surroundings. To outline how interactions among participants, acting in relation with changing surroundings, achieve collective outcomes, I focus on three aspects of collective behavior: the rate at which interactions adjust to conditions, the feedback regime that stimulates and inhibits activity, and the modularity of the network of interactions. To characterize the dynamics of the surroundings, I consider gradients in stability, energy flow, and the distribution of resources and demands. I then propose some hypotheses that link how collective behavior operates with changing environments.
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Affiliation(s)
- Deborah M Gordon
- Department of Biology, Stanford University, Stanford, California, USA
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2
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Das B, Gordon DM. Biological rhythms and task allocation in ant colonies. Curr Opin Insect Sci 2023:101062. [PMID: 37247773 DOI: 10.1016/j.cois.2023.101062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/15/2023] [Accepted: 05/23/2023] [Indexed: 05/31/2023]
Abstract
Task allocation in ant colonies, mediated by social interactions, regulates which individuals perform each task, and when they are active, in response to the current situation. Many tasks are performed in a daily temporal pattern. An ant's biological clock depends on patterns of gene expression that are regulated using a negative feedback loop which is synchronized to earth's rotation by external cues. An individual's biological clock can shift in response to social cues, and this plasticity contributes to task switching. Daily rhythms in individual ant behavior combine, via interactions within and across task groups, to adjust the collective behavior of colonies. Further work is needed to elucidate how the social cues that lead to task switching influence the molecular mechanisms that generate clock outputs associated with each task, and to investigate the evolution of temporal patterns in task allocation in relation to ecological factors.
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Adler FR, Anderson ARA, Bhushan A, Bogdan P, Bravo-Cordero JJ, Brock A, Chen Y, Cukierman E, DelGiorno KE, Denis GV, Ferrall-Fairbanks MC, Gartner ZJ, Germain RN, Gordon DM, Hunter G, Jolly MK, Karacosta LG, Mythreye K, Katira P, Kulkarni RP, Kutys ML, Lander AD, Laughney AM, Levine H, Lou E, Lowenstein PR, Masters KS, Pe'er D, Peyton SR, Platt MO, Purvis JE, Quon G, Richer JK, Riddle NC, Rodriguez A, Snyder JC, Lee Szeto G, Tomlin CJ, Yanai I, Zervantonakis IK, Dueck H. Modeling collective cell behavior in cancer: Perspectives from an interdisciplinary conversation. Cell Syst 2023; 14:252-257. [PMID: 37080161 PMCID: PMC10760508 DOI: 10.1016/j.cels.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/20/2022] [Accepted: 03/08/2023] [Indexed: 04/22/2023]
Abstract
Collective cell behavior contributes to all stages of cancer progression. Understanding how collective behavior emerges through cell-cell interactions and decision-making will advance our understanding of cancer biology and provide new therapeutic approaches. Here, we summarize an interdisciplinary discussion on multicellular behavior in cancer, draw lessons from other scientific disciplines, and identify future directions.
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Affiliation(s)
- Frederick R Adler
- Department of Mathematics, University of Utah, Salt Lake City, UT 84112, USA; School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Alexander R A Anderson
- Integrated Mathematical Oncology Department, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA
| | - Abhinav Bhushan
- Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Paul Bogdan
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Jose Javier Bravo-Cordero
- Division of Hematology and Oncology, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Amy Brock
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Yun Chen
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Edna Cukierman
- Cancer Signaling and Microenvironment Program, Marvin and Concetta Greenberg Pancreatic Cancer Institute, Fox Chase Cancer Center, Philadelphia, PA 19111, USA; Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Kathleen E DelGiorno
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Gerald V Denis
- Boston University-Boston Medical Center Cancer Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Meghan C Ferrall-Fairbanks
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA; University of Florida Health Cancer Center, University of Florida, Gainesville, FL 32611, USA
| | - Zev Jordan Gartner
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA; NSF Center for Cellular Construction, San Francisco, CA 94158, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Ronald N Germain
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Deborah M Gordon
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Ginger Hunter
- Department of Biology, Clarkson University, Potsdam, NY 13699, USA
| | - Mohit Kumar Jolly
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, 560012, India
| | - Loukia Georgiou Karacosta
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Karthikeyan Mythreye
- Department of Pathology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA; O'Neal Comprehensive Cancer Center, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Parag Katira
- Mechanical Engineering Department, San Diego State University, San Diego, CA 92182, USA; Computational Sciences Research Center, San Diego State University, San Diego, CA 92182, USA
| | - Rajan P Kulkarni
- Department of Dermatology, Oregon Health and Science University, Portland, OR 97239, USA; Department Biomedical Engineering, Oregon Health and Science University, Portland, OR 97239, USA; Department Oncological Sciences, Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA; Cancer Early Detection Advanced Research Center (CEDAR), Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA; Operative Care Division, VA Portland Health Care System, Portland, OR 97239, USA
| | - Matthew L Kutys
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Arthur D Lander
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA; Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697, USA
| | - Ashley M Laughney
- Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY 10021, USA; Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10021, USA; Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Herbert Levine
- Center for Theoretical Biological Physics, Northeastern University, Boston, MA 02115, USA
| | - Emil Lou
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Pedro R Lowenstein
- Department of Neurosurgery, Rogel Cancer Center, The University of Michigan, Ann Arbor, MI 48109, USA; Department of Cell and Developmental Biology, Rogel Cancer Center, The University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Kristyn S Masters
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Dana Pe'er
- Computational and Systems Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Shelly R Peyton
- Department of Chemical Engineering, University of Massachusetts, Amherst, MA 01003, USA
| | - Manu O Platt
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, Atlanta, GA 30322, USA; Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Emory University, Atlanta, GA 30322, USA
| | - Jeremy E Purvis
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Gerald Quon
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Jennifer K Richer
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; University of Colorado Cancer Center, Aurora, CO 80045, USA
| | - Nicole C Riddle
- Department of Biology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Analiz Rodriguez
- Department of Neurosurgery, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Joshua C Snyder
- Department of Surgery, Duke University, Durham, NC 27710, USA; Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Gregory Lee Szeto
- Allen Institute for Immunology, Seattle, WA 98109, USA; Seagen, Bothell, WA 98021, USA
| | - Claire J Tomlin
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Itai Yanai
- Perlmutter Cancer Center, NYU School of Medicine, New York, NY 10016, USA; Institute for Computational Medicine, NYU Langone Health, New York, NY 10016, USA
| | - Ioannis K Zervantonakis
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15232, USA; Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15232, USA
| | - Hannah Dueck
- Division of Cancer Biology, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, USA.
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Nelson RA, MacArthur-Waltz DJ, Gordon DM. Critical thermal limits and temperature-dependent walking speed may mediate coexistence between the native winter ant (Prenolepis imparis) and the invasive Argentine ant (Linepithemahumile). J Therm Biol 2023; 111:103392. [PMID: 36585081 DOI: 10.1016/j.jtherbio.2022.103392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 10/27/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022]
Abstract
Comparing the thermal tolerance and performance of native and invasive species from varying climatic origins may explain why some native and invasive species can coexist. We compared the thermal niches of an invasive and native ant species. The Argentine ant (Linepithema humile) is an invasive species that has spread to Mediterranean climates worldwide, where it is associated with losses in native arthropod biodiversity. In northern California, long-term surveys of ant biodiversity have shown that the winter ant (Prenolepis imparis) is the native species best able to coexist with Argentine ants. Both species tend hemipteran scales for food, and previous research suggests that these species' coexistence may depend on seasonal partitioning: winter ants are active primarily in the colder winter months, while Argentine ants are active primarily in the warmer months in northern California. We investigated the physiological basis of seasonal partitioning in Argentine and winter ants by a) measuring critical thermal limits, and b) comparing how ant walking speed varies with temperature. While both species had similar CTmax values, we found differences between the two species' critical thermal minima that may allow winter ants to remain functional at ecologically relevant temperatures between 0 and 2.5 °C. We also found that winter ants' walking speeds are significantly less temperature-dependent than those of Argentine ants. Winter ants walk faster than Argentine ants at low temperatures, which may allow the winter ants to remain active and forage at lower winter temperatures. These results suggest that partitioning based on differences in temperature tolerance promotes the winter ant's continued occupation of areas invaded by the Argentine ant.
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Affiliation(s)
- Rebecca A Nelson
- Stanford University Department of Biology, 371 Jane Stanford Way, Stanford, CA, 94305, United States.
| | - Dylan J MacArthur-Waltz
- Stanford University Department of Biology, 371 Jane Stanford Way, Stanford, CA, 94305, United States.
| | - Deborah M Gordon
- Stanford University Department of Biology, 371 Jane Stanford Way, Stanford, CA, 94305, United States.
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Nova N, Pagliara R, Gordon DM. Individual Variation Does Not Regulate Foraging Response to Humidity in Harvester Ant Colonies. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2021.756204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Differences among groups in collective behavior may arise from responses that all group members share, or instead from differences in the distribution of individuals of particular types. We examined whether the collective regulation of foraging behavior in colonies of the desert red harvester ant (Pogonomyrmex barbatus) depends on individual differences among foragers. Foragers lose water while searching for seeds in hot, dry conditions, so colonies regulate foraging activity in response to humidity. In the summer, foraging activity begins in the early morning when humidity is high, and ends at midday when humidity is low. We investigated whether individual foragers within a colony differ in the decision whether to leave the nest on their next foraging trip as humidity decreases, by tracking the foraging trips of marked individuals. We found that individuals did not differ in response to current humidity. No ants were consistently more likely than others to stop foraging when humidity is low. Each day there is a skewed distribution of trip number: only a few individuals make many trips, but most individuals make few trips. We found that from one day to the next, individual foragers do not show any consistent tendency to make a similar number of trips. These results suggest that the differences among colonies in response to humidity, found in previous work, are due to behavioral responses to current humidity that all workers in a colony share, rather than to the distribution within a colony of foragers that differ in response.
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Sundaram M, Steiner E, Gordon DM. Rainfall, neighbors, and foraging: The dynamics of a population of red harvester ant colonies 1988‐2019. ECOL MONOGR 2022. [DOI: 10.1002/ecm.1503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Erik Steiner
- Center for Spatial and Textual Analysis Stanford University Stanford CA
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Abstract
Spatial patterns of movement regulate many aspects of social insect behavior, because how workers move around, and how many are there, determines how often they meet and interact. Interactions are usually olfactory; for example, in ants, by means of antennal contact in which one worker assesses the cuticular hydrocarbons of another. Encounter rates may be a simple outcome of local density: a worker experiences more encounters, the more other workers there are around it. This means that encounter rate can be used as a cue for overall density even though no individual can assess global density. Encounter rate as a cue for local density regulates many aspects of social insect behavior, including collective search, task allocation, nest choice, and traffic flow. As colonies grow older and larger, encounter rates change, which leads to changes in task allocation. Nest size affects local density and movement patterns, which influences encounter rate, so that nest size and connectivity influence colony behavior. However, encounter rate is not a simple function of local density when individuals change their movement in response to encounters, thus influencing further encounter rates. Natural selection on the regulation of collective behavior can draw on variation within and among colonies in the relation of movement patterns, encounter rate, and response to encounters.
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Couper LI, Sanders NJ, Heller NE, Gordon DM. Multiyear drought exacerbates long-term effects of climate on an invasive ant species. Ecology 2021; 102:e03476. [PMID: 34346070 PMCID: PMC9285587 DOI: 10.1002/ecy.3476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/06/2021] [Accepted: 07/08/2021] [Indexed: 11/09/2022]
Abstract
Invasive species threaten biodiversity, ecosystem function, and human health, but the long-term drivers of invasion dynamics remain poorly understood. We use data from a 28-yr ongoing survey of a Northern California ant community invaded by the Argentine ant (Linepithema humile) to investigate the influence of abiotic and biotic factors on invasion dynamics. We found that the distribution of L. humile retracted following an extreme drought that occurred in the region from 2012 to 2015. The distribution of several native ant species also contracted, but overall native ant diversity was higher after the drought and for some native ant species, distributions expanded over the 28-yr survey period. Using structural equation models, we found the strongest impact on the distribution of L. humile was from direct effects of climate, namely, cumulative precipitation and summer maximum temperatures, with only a negligible role for biotic resistance and indirect effects of climate mediated by native ants. The increasing drought and high temperature extremes projected for northern California because of anthropogenic-driven climate change may limit the spread, and possibly the impact, of L. humile in invaded regions. The outcome will depend on the response of native ant communities to these climatic stressors.
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Affiliation(s)
- Lisa I Couper
- Department of Biology, Stanford University, Stanford, California, USA
| | - Nathan J Sanders
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Nicole E Heller
- Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA
| | - Deborah M Gordon
- Department of Biology, Stanford University, Stanford, California, USA
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Gordon DM. Variation and change in behavior: a comment on Loftus et al. Behav Ecol 2020. [DOI: 10.1093/beheco/araa116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Friedman DA, York RA, Hilliard AT, Gordon DM. Gene expression variation in the brains of harvester ant foragers is associated with collective behavior. Commun Biol 2020; 3:100. [PMID: 32139795 PMCID: PMC7057964 DOI: 10.1038/s42003-020-0813-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 02/10/2020] [Indexed: 01/10/2023] Open
Abstract
Natural selection on collective behavior acts on variation among colonies in behavior that is associated with reproductive success. In the red harvester ant (Pogonomyrmex barbatus), variation among colonies in the collective regulation of foraging in response to humidity is associated with colony reproductive success. We used RNA-seq to examine gene expression in the brains of foragers in a natural setting. We find that colonies differ in the expression of neurophysiologically-relevant genes in forager brains, and a fraction of these gene expression differences are associated with two colony traits: sensitivity of foraging activity to humidity, and forager brain dopamine to serotonin ratio. Loci that were correlated with colony behavioral differences were enriched in neurotransmitter receptor signaling & metabolic functions, tended to be more central to coexpression networks, and are evolving under higher protein-coding sequence constraint. Natural selection may shape colony foraging behavior through variation in gene expression.
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Affiliation(s)
| | | | | | - Deborah M Gordon
- Stanford University, Department of Biology, Stanford, CA, 94305, USA.
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El Hady A, Davidson JD, Gordon DM. Editorial: An Ecological Perspective on Decision-Making: Empirical and Theoretical Studies in Natural and Natural-Like Environments. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
Collective behavior is ubiquitous throughout nature. Many systems, from brains to ant colonies, work without central control. Collective behavior is regulated by interactions among the individual participants such as neurons or ants. Interactions create feedback that produce the outcome, the behavior that we observe: Brains think and remember, ant colonies collect food or move nests, flocks of birds turn, human societies develop new forms of social organization. But the processes by which interactions produce outcomes are as diverse as the behavior itself. Just as convergent evolution has led to organs, such as the eye, that are similar in function but are based on different physiological processes, so it has led to forms of collective behavior that appear similar but arise from different social processes. An ecological perspective can help us to understand the dynamics of collective behavior and how it works.
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Abstract
Parallels of cancer with ecology and evolution have provided new insights into the initiation and spread of cancer, and new approaches to therapy. This review describes those parallels while emphasizing some key contrasts. We argue that cancers are less like invasive species than like native species or even crops that have escaped control, and that ecological control and homeo-static control differ fundamentally through both their ends and their means. From our focus on the role of positive interactions in control processes, we introduce a novel mathematical modeling framework that tracks how individual cell lineages arise, and how the many layers of control break down in the emergence of cancer. The next generation of therapies must continue to look beyond cancers as being created by individual renegade cells and address not only the network of interactions those cells inhabit, but the evolutionary logic that created those interactions and their intrinsic vulnerability.
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Affiliation(s)
- Frederick R Adler
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112.,Department of Mathematics, University of Utah, 155 South 1400 East, Salt Lake City, UT 84112
| | - Deborah M Gordon
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305-5020
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Abstract
There are striking similarities between the strategies ant colonies use to forage for food and immune systems use to search for pathogens. Searchers (ants and cells) use the appropriate combination of random and directed motion, direct and indirect agent-agent interactions, and traversal of physical structures to solve search problems in a variety of environments. An effective immune response requires immune cells to search efficiently and effectively for diverse types of pathogens in different tissues and organs, just as different species of ants have evolved diverse search strategies to forage effectively for a variety of resources in a variety of habitats. Successful T cell search is required to initiate the adaptive immune response in lymph nodes and to eradicate pathogens at sites of infection in peripheral tissue. Ant search strategies suggest novel predictions about T cell search. In both systems, the distribution of targets in time and space determines the most effective search strategy. We hypothesize that the ability of searchers to sense and adapt to dynamic targets and environmental conditions enhances search effectiveness through adjustments to movement and communication patterns. We also suggest that random motion is a more important component of search strategies than is generally recognized. The behavior we observe in ants reveals general design principles and constraints that govern distributed adaptive search in a wide variety of complex systems, particularly the immune system.
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Affiliation(s)
- Melanie E Moses
- Moses Biological Computation Laboratory, Department of Computer Science, University of New Mexico, Albuquerque, NM, United States.,Biology Department, University of New Mexico, Albuquerque, NM, United States.,Santa Fe Institute, Santa Fe, NM, United States
| | - Judy L Cannon
- The Cannon Laboratory, Department of Molecular Genetics & Microbiology, University of New Mexico School of Medicine, Albuquerque, NM, United States.,Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM, United States.,Autophagy, Inflammation, and Metabolism Center of Biomedical Research Excellence, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Deborah M Gordon
- Santa Fe Institute, Santa Fe, NM, United States.,Department of Biology, Stanford University, Stanford, CA, United States
| | - Stephanie Forrest
- Santa Fe Institute, Santa Fe, NM, United States.,Biodesign Institute and School for Computing, Informatics, and Decision Sciences Engineering, Arizona State University, Tempe, AZ, United States
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Friedman DA, Greene MJ, Gordon DM. The physiology of forager hydration and variation among harvester ant (Pogonomyrmex barbatus) colonies in collective foraging behavior. Sci Rep 2019; 9:5126. [PMID: 30914705 PMCID: PMC6435751 DOI: 10.1038/s41598-019-41586-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 03/11/2019] [Indexed: 01/31/2023] Open
Abstract
Ants are abundant in desiccating environments despite their high surface area to volume ratios and exposure to harsh conditions outside the nest. Red harvester ant (Pogonomyrmex barbatus) colonies must spend water to obtain water: colonies lose water as workers forage outside the nest, and gain water metabolically through seeds collected in foraging trips. Here we present field experiments showing that hydrated P. barbatus foragers made more foraging trips than unhydrated nestmates. The positive effect of hydration on foraging activity is stronger as the risk of desiccation increases. Desiccation tests showed that foragers of colonies that reduce foraging in dry conditions are more sensitive to water loss, losing water and motor coordination more rapidly in desiccating conditions, than foragers of colonies that do not reduce foraging in dry conditions. Desiccation tolerance is also associated with colony reproductive success. Surprisingly, foragers that are more sensitive to water loss are from colonies more likely to produce offspring colonies. This could be because the foragers of these colonies conserve water with a more cautious response to desiccation risk. An ant's hydration status may influence its response to the olfactory interactions that regulate its decision to leave the nest to forage. Thus variation among ant colonies in worker physiology and response to ambient conditions may contribute to ecologically significant differences among colonies in collective behavior.
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Affiliation(s)
- Daniel A Friedman
- Department of Biology, Stanford University, Stanford, California, USA.
| | - Michael J Greene
- Department of Integrative Biology, University of Colorado Denver, Denver, Colorado, USA
| | - Deborah M Gordon
- Department of Biology, Stanford University, Stanford, California, USA
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16
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Abstract
Nest choice in Temnothorax spp.; task allocation and the regulation of activity in Pheidole dentata, Pogonomyrmex barbatus, and Atta spp.; and trail networks in Monomorium pharaonis and Cephalotes goniodontus all provide examples of correspondences between the dynamics of the environment and the dynamics of collective behavior. Some important aspects of the dynamics of the environment include stability, the threat of rupture or disturbance, the ratio of inflow and outflow of resources or energy, and the distribution of resources. These correspond to the dynamics of collective behavior, including the extent of amplification, how feedback instigates and inhibits activity, and the extent to which the interactions that provide the information to regulate behavior are local or spatially centralized.
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Affiliation(s)
- Deborah M Gordon
- Department of Biology, Stanford University, Stanford, California 94305-5020, USA;
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17
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Pagliara R, Gordon DM, Leonard NE. Regulation of harvester ant foraging as a closed-loop excitable system. PLoS Comput Biol 2018; 14:e1006200. [PMID: 30513076 PMCID: PMC6294393 DOI: 10.1371/journal.pcbi.1006200] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 12/14/2018] [Accepted: 11/05/2018] [Indexed: 11/19/2022] Open
Abstract
Ant colonies regulate activity in response to changing conditions without using centralized control. Desert harvester ant colonies forage for seeds, and regulate foraging to manage a tradeoff between spending and obtaining water. Foragers lose water while outside in the dry air, but ants obtain water by metabolizing the fats in the seeds they eat. Previous work shows that the rate at which an outgoing forager leaves the nest depends on its recent rate of brief antennal contacts with incoming foragers carrying food. We examine how this process can yield foraging rates that are robust to uncertainty and responsive to temperature and humidity across minute-to-hour timescales. To explore possible mechanisms, we develop a low-dimensional analytical model with a small number of parameters that captures observed foraging behavior. The model uses excitability dynamics to represent response to interactions inside the nest and a random delay distribution to represent foraging time outside the nest. We show how feedback from outgoing foragers returning to the nest stabilizes the incoming and outgoing foraging rates to a common value determined by the volatility of available foragers. The model exhibits a critical volatility above which there is sustained foraging at a constant rate and below which foraging stops. To explain how foraging rates adjust to temperature and humidity, we propose that foragers modify their volatility after they leave the nest and become exposed to the environment. Our study highlights the importance of feedback in the regulation of foraging activity and shows how modulation of volatility can explain how foraging activity responds to conditions and varies across colonies. Our model elucidates the role of feedback across many timescales in collective behavior, and may be generalized to other systems driven by excitable dynamics, such as neuronal networks.
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Affiliation(s)
- Renato Pagliara
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, United States of America
| | - Deborah M. Gordon
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Naomi Ehrich Leonard
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, United States of America
- * E-mail:
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Friedman DA, Pilko A, Skowronska-Krawczyk D, Krasinska K, Parker JW, Hirsh J, Gordon DM. The Role of Dopamine in the Collective Regulation of Foraging in Harvester Ants. iScience 2018; 8:283-294. [PMID: 30270022 PMCID: PMC6205345 DOI: 10.1016/j.isci.2018.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/04/2018] [Accepted: 09/03/2018] [Indexed: 01/09/2023] Open
Abstract
Colonies of the red harvester ant (Pogonomyrmex barbatus) differ in how they regulate collective foraging activity in response to changes in humidity. We used transcriptomic, physiological, and pharmacological experiments to investigate the molecular basis of this ecologically important variation in collective behavior among colonies. RNA sequencing of forager brain tissue showed an association between colony foraging activity and differential expression of transcripts related to biogenic amine and neurohormonal metabolism and signaling. In field experiments, pharmacological increases in forager brain dopamine titer caused significant increases in foraging activity. Colonies that were naturally most sensitive to humidity were significantly more responsive to the stimulatory effect of exogenous dopamine. In addition, forager brain tissue significantly varied among colonies in biogenic amine content. Neurophysiological variation among colonies associated with individual forager sensitivity to humidity may reflect the heritable molecular variation on which natural selection acts to shape the collective regulation of foraging.
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Affiliation(s)
- Daniel A Friedman
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Anna Pilko
- Department of Chemistry and Biochemistry and the Institute for Quantitative and Computational Biosciences (QCB), University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Dorota Skowronska-Krawczyk
- Shiley Eye Institute, Richard C. Atkinson Lab for Regenerative Ophthalmology, Department of Ophthalmology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Karolina Krasinska
- Stanford University Mass Spectrometry, Stanford University, Stanford, CA 94305, USA
| | - Jacqueline W Parker
- Department of Biology, University of Virginia, Charlottesville, Charlottesville, VA 22904, USA
| | - Jay Hirsh
- Department of Biology, University of Virginia, Charlottesville, Charlottesville, VA 22904, USA
| | - Deborah M Gordon
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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Burford BP, Lee G, Friedman DA, Brachmann E, Khan R, MacArthur-Waltz DJ, McCarty AD, Gordon DM. Foraging behavior and locomotion of the invasive Argentine ant from winter aggregations. PLoS One 2018; 13:e0202117. [PMID: 30092038 PMCID: PMC6084982 DOI: 10.1371/journal.pone.0202117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 07/27/2018] [Indexed: 11/19/2022] Open
Abstract
The collective behavior of ant colonies, and locomotion of individuals within a colony, both respond to changing conditions. The invasive Argentine ant (Linepithema humile) thrives in Mediterranean climates with hot, dry summers and colder, wet winters. However, its foraging behavior and locomotion has rarely been studied in the winter. We examined how the foraging behavior of three distinct L. humile colonies was related to environmental conditions and the locomotion of workers during winter in northern California. We found that colonies foraged most between 10 and 15°C, regardless of the maximum daily temperature. Worker walking speed was positively associated with temperature (range 6-24°C) and negatively associated with humidity (range 25-93%RH). All colonies foraged during all day and night hours in a predictable daily cycle, with a correlation between the rate of incoming and outgoing foragers. Foraging activity was unrelated to the activity of a competing native ant species, Prenolepis imparis, which was present in low abundance, and ceased only during heavy rain when ants left foraging trails and aggregated in small sheltered areas on trees.
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Affiliation(s)
- Benjamin P. Burford
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Gail Lee
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Daniel A. Friedman
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Esmé Brachmann
- College of Letters & Science, University of California Berkeley, Berkeley, California, United States of America
| | - Rebia Khan
- Department of Biology, Stanford University, Stanford, California, United States of America
| | | | - Aidan D. McCarty
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Deborah M. Gordon
- Department of Biology, Stanford University, Stanford, California, United States of America
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Chandrasekhar A, Gordon DM, Navlakha S. A distributed algorithm to maintain and repair the trail networks of arboreal ants. Sci Rep 2018; 8:9297. [PMID: 29915325 PMCID: PMC6006367 DOI: 10.1038/s41598-018-27160-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 05/24/2018] [Indexed: 11/09/2022] Open
Abstract
We study how the arboreal turtle ant (Cephalotes goniodontus) solves a fundamental computing problem: maintaining a trail network and finding alternative paths to route around broken links in the network. Turtle ants form a routing backbone of foraging trails linking several nests and temporary food sources. This species travels only in the trees, so their foraging trails are constrained to lie on a natural graph formed by overlapping branches and vines in the tangled canopy. Links between branches, however, can be ephemeral, easily destroyed by wind, rain, or animal movements. Here we report a biologically feasible distributed algorithm, parameterized using field data, that can plausibly describe how turtle ants maintain the routing backbone and find alternative paths to circumvent broken links in the backbone. We validate the ability of this probabilistic algorithm to circumvent simulated breaks in synthetic and real-world networks, and we derive an analytic explanation for why certain features are crucial to improve the algorithm's success. Our proposed algorithm uses fewer computational resources than common distributed graph search algorithms, and thus may be useful in other domains, such as for swarm computing or for coordinating molecular robots.
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Affiliation(s)
- Arjun Chandrasekhar
- The Salk Institute for Biological Studies, Integrative Biology Laboratory, La Jolla, CA, 92037, USA
| | - Deborah M Gordon
- Department of Biology, Stanford University, Stanford, CA, 94035, USA.
| | - Saket Navlakha
- The Salk Institute for Biological Studies, Integrative Biology Laboratory, La Jolla, CA, 92037, USA.
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Davidson JD, Gordon DM. Spatial organization and interactions of harvester ants during foraging activity. J R Soc Interface 2018; 14:rsif.2017.0413. [PMID: 28978748 DOI: 10.1098/rsif.2017.0413] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Accepted: 09/11/2017] [Indexed: 11/12/2022] Open
Abstract
Local interactions, when individuals meet, can regulate collective behaviour. In a system without any central control, the rate of interaction may depend simply on how the individuals move around. But interactions could in turn influence movement; individuals might seek out interactions, or their movement in response to interaction could influence further interaction rates. We develop a general framework to address these questions, using collision theory to establish a baseline expected rate of interaction based on proximity. We test the models using data from harvester ant colonies. A colony uses feedback from interactions inside the nest to regulate foraging activity. Potential foragers leave the nest in response to interactions with returning foragers with food. The time series of interactions and local density of ants show how density hotspots lead to interactions that are clustered in time. A correlated random walk null model describes the mixing of potential and returning foragers. A model from collision theory relates walking speed and spatial proximity with the probability of interaction. The results demonstrate that although ants do not mix homogeneously, trends in interaction patterns can be explained simply by the walking speed and local density of surrounding ants.
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Affiliation(s)
- Jacob D Davidson
- Department of Collective Behavior, Max Planck Institute for Ornithology, Konstanz, Germany .,Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
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Ingram KK, Gordon DM, Friedman DA, Greene M, Kahler J, Peteru S. Context-dependent expression of the foraging gene in field colonies of ants: the interacting roles of age, environment and task. Proc Biol Sci 2017; 283:rspb.2016.0841. [PMID: 27581876 PMCID: PMC5013789 DOI: 10.1098/rspb.2016.0841] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 08/05/2016] [Indexed: 12/31/2022] Open
Abstract
Task allocation among social insect workers is an ideal framework for studying the molecular mechanisms underlying behavioural plasticity because workers of similar genotype adopt different behavioural phenotypes. Elegant laboratory studies have pioneered this effort, but field studies involving the genetic regulation of task allocation are rare. Here, we investigate the expression of the foraging gene in harvester ant workers from five age- and task-related groups in a natural population, and we experimentally test how exposure to light affects foraging expression in brood workers and foragers. Results from our field study show that the regulation of the foraging gene in harvester ants occurs at two time scales: levels of foraging mRNA are associated with ontogenetic changes over weeks in worker age, location and task, and there are significant daily oscillations in foraging expression in foragers. The temporal dissection of foraging expression reveals that gene expression changes in foragers occur across a scale of hours and the level of expression is predicted by activity rhythms: foragers have high levels of foraging mRNA during daylight hours when they are most active outside the nests. In the experimental study, we find complex interactions in foraging expression between task behaviour and light exposure. Oscillations occur in foragers following experimental exposure to 13 L : 11 D (LD) conditions, but not in brood workers under similar conditions. No significant differences were seen in foraging expression over time in either task in 24 h dark (DD) conditions. Interestingly, the expression of foraging in both undisturbed field and experimentally treated foragers is also significantly correlated with the expression of the circadian clock gene, cycle. Our results provide evidence that the regulation of this gene is context-dependent and associated with both ontogenetic and daily behavioural plasticity in field colonies of harvester ants. Our results underscore the importance of assaying temporal patterns in behavioural gene expression and suggest that gene regulation is an integral mechanism associated with behavioural plasticity in harvester ants.
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Affiliation(s)
- Krista K Ingram
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Deborah M Gordon
- Department of Biology, Stanford University, Gilbert Biological Science Building, Stanford, CA 94305, USA
| | - Daniel A Friedman
- Department of Biology, Stanford University, Gilbert Biological Science Building, Stanford, CA 94305, USA
| | - Michael Greene
- Department of Integrative Biology, University of Colorado, Campus Box 171, PO Box 176634, Denver, CO 80217-3364, USA
| | - John Kahler
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Swetha Peteru
- Department of Geography, Texas A&M University, College Station, TX 77843, USA
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Abstract
This study examines how an arboreal ant colony maintains, extends, and repairs its network of foraging trails and nests, built on a network of vegetation. Nodes are junctions where a branch forks off from another or where a branch of one plant touching another provides a new edge on which ants could travel. The ants' choice of edge at a node appears to be reinforced by trail pheromone. Ongoing pruning of the network tends to eliminate cycles and minimize the number of nodes and thus decision points, but not the distance traveled. At junctions, trails tend to stay on the same plant. In combination with the long internode lengths of the branches of vines in the tropical dry forest, this facilitates travel to food sources at the canopy edge. Exploration, when ants leave the trail on an edge that is not being used, makes both search and repair possible. The fewer the junctions between a location and the main trail, the more likely the ants are to arrive there. Ruptured trails are rapidly repaired with a new path, apparently using breadth-first search. The regulation of the network promotes its resilience and continuity.
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Gordon DM. Addendum: The rewards of restraint in the collective regulation of foraging by harvester ant colonies. Nature 2017; 542:260. [DOI: 10.1038/nature21057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Harvester ant colonies adjust their foraging activity to day-to-day changes in food availability and hour-to-hour changes in environmental conditions. This collective behavior is regulated through interactions, in the form of brief antennal contacts, between outgoing foragers and returning foragers with food. Here we consider how an ant, waiting in the entrance chamber just inside the nest entrance, uses its accumulated experience of interactions to decide whether to leave the nest to forage. Using videos of field observations, we tracked the interactions and foraging decisions of ants in the entrance chamber. Outgoing foragers tended to interact with returning foragers at higher rates than ants that returned to the deeper nest and did not forage. To provide a mechanistic framework for interpreting these results, we develop a decision model in which ants make decisions based upon a noisy accumulation of individual contacts with returning foragers. The model can reproduce core trends and realistic distributions for individual ant interaction statistics, and suggests possible mechanisms by which foraging activity may be regulated at an individual ant level.
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Affiliation(s)
- Jacob D. Davidson
- Center for Neuroscience, University of California, Davis, Davis, CA, USA
| | | | - Sam Crow
- Department of Computer Science and Engineering, University of Washington, Seattle, WA, USA
| | | | - Mark S. Goldman
- Center for Neuroscience, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
- Department of Ophthalmology and Vision Science, University of California, Davis, Davis, CA, USA
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Jandt JM, Gordon DM. The behavioral ecology of variation in social insects. Curr Opin Insect Sci 2016; 15:40-44. [PMID: 27436730 DOI: 10.1016/j.cois.2016.02.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 02/22/2016] [Accepted: 02/23/2016] [Indexed: 06/06/2023]
Abstract
Understanding the ecological relevance of variation within and between colonies has been an important and recurring theme in social insect research. Recent research addresses the genomic and physiological factors and fitness effects associated with behavioral variation, within and among colonies, in regulation of activity, cognitive abilities, and aggression. Behavioral variation among colonies has consequences for survival and reproductive success that are the basis for evolutionary change.
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Affiliation(s)
- J M Jandt
- Iowa State University, Department of Ecology, Evolution, and Organismal Biology, 251 Bessey Hall, Ames, IA 50011, USA.
| | - D M Gordon
- Stanford University, Department of Biology, Gilbert Biological Sciences Building, rm 410, 371 Serra Mall, Stanford, CA 94305, USA
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Abstract
Many exciting studies have begun to elucidate the genetics of the morphological and physiological diversity of ants, but as yet few studies have investigated the genetics of ant behavior directly. Ant genomes are marked by extreme rates of gene turnover, especially in gene families related to olfactory communication, such as the synthesis of cuticular hydrocarbons and the perception of environmental semiochemicals. Transcriptomic and epigenetic differences are apparent between reproductive and sterile females, males and females, and workers that differ in body size. Quantitative genetic approaches suggest heritability of task performance, and population genetic studies indicate a genetic association with reproductive status in some species. Gene expression is associated with behavior including foraging, response to queens attempting to join a colony, circadian patterns of task performance, and age-related changes of task. Ant behavioral genetics needs further investigation of the feedback between individual-level physiological changes and socially mediated responses to environmental conditions.
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Affiliation(s)
- D A Friedman
- Department of Biology, Stanford University, Stanford, California 94305-5020;
| | - D M Gordon
- Department of Biology, Stanford University, Stanford, California 94305-5020;
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Dosmann A, Bahet N, Gordon DM. Experimental modulation of external microbiome affects nestmate recognition in harvester ants (Pogonomyrmex barbatus). PeerJ 2016; 4:e1566. [PMID: 26855857 PMCID: PMC4741111 DOI: 10.7717/peerj.1566] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/15/2015] [Indexed: 12/17/2022] Open
Abstract
Social insects use odors as cues for a variety of behavioral responses, including nestmate recognition. Past research on nestmate recognition indicates cuticular hydrocarbons are important nestmate discriminators for social insects, but other factors are likely to contribute to colony-specific odors. Here we experimentally tested whether external microbes contribute to nestmate recognition in red harvester ants (Pogonomyrmex barbatus). We changed the external microbiome of ants through topical application of either antibiotics or microbial cultures. We then observed behavior of nestmates when treated ants were returned to the nest. Ants whose external microbiome was augmented with microbial cultures were much more likely to be rejected than controls, but ants treated with antibiotics were not. This result is consistent with the possibility that external microbes are used for nestmate recognition.
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Affiliation(s)
- Andy Dosmann
- Department of Natural Sciences, Minerva Schools at Keck Graduate Institute , San Francisco, CA , United States
| | - Nassim Bahet
- Stanford Online High School, Stanford, CA, United States; Department of Biology, Stanford University, Stanford, CA, United States
| | - Deborah M Gordon
- Department of Biology, Stanford University , Stanford, CA , United States
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Gordon DM. From division of labor to the collective behavior of social insects. Behav Ecol Sociobiol 2015; 70:1101-1108. [PMID: 27397966 PMCID: PMC4917577 DOI: 10.1007/s00265-015-2045-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/11/2015] [Accepted: 11/18/2015] [Indexed: 12/03/2022]
Abstract
‘Division of labor’ is a misleading way to describe the organization of tasks in social insect colonies, because there is little evidence for persistent individual specialization in task. Instead, task allocation in social insects occurs through distributed processes whose advantages, such as resilience, differ from those of division of labor, which are mostly based on learning. The use of the phrase ‘division of labor’ persists for historical reasons, and tends to focus attention on differences among individuals in internal attributes. This focus distracts from the main questions of interest in current research, which require an understanding of how individuals interact with each other and their environments. These questions include how colony behavior is regulated, how the regulation of colony behavior develops over the lifetime of a colony, what are the sources of variation among colonies in the regulation of behavior, and how the collective regulation of colony behavior evolves.
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Affiliation(s)
- Deborah M Gordon
- Department of Biology, Stanford University, Stanford, CA 94305-5020 USA
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Pless E, Queirolo J, Pinter-Wollman N, Crow S, Allen K, Mathur MB, Gordon DM. Interactions Increase Forager Availability and Activity in Harvester Ants. PLoS One 2015; 10:e0141971. [PMID: 26539724 PMCID: PMC4635008 DOI: 10.1371/journal.pone.0141971] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/15/2015] [Indexed: 11/27/2022] Open
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.
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Affiliation(s)
- Evlyn Pless
- Department of Biology, Stanford University, Stanford, California, United States of America
- * E-mail:
| | - Jovel Queirolo
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Noa Pinter-Wollman
- BioCircuits Institute, University of California, San Diego, La Jolla, California, United States of America
| | - Sam Crow
- Department of Computer Science and Engineering, University of Washington, Seattle, Washington, United States of America
| | - Kelsey Allen
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Maya B. Mathur
- Quantitative Sciences Unit, Stanford University, Stanford, California, United States of America
| | - Deborah M. Gordon
- Department of Biology, Stanford University, Stanford, California, United States of America
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Countryman SM, Stumpe MC, Crow SP, Adler FR, Greene MJ, Vonshak M, Gordon DM. Corrigendum: Collective search by ants in microgravity. Front Ecol Evol 2015. [DOI: 10.3389/fevo.2015.00062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
We propose a distributed model of nestmate recognition, analogous to the one used by the vertebrate immune system, in which colony response results from the diverse reactions of many ants. The model describes how individual behaviour produces colony response to non-nestmates. No single ant knows the odour identity of the colony. Instead, colony identity is defined collectively by all the ants in the colony. Each ant responds to the odour of other ants by reference to its own unique decision boundary, which is a result of its experience of encounters with other ants. Each ant thus recognizes a particular set of chemical profiles as being those of non-nestmates. This model predicts, as experimental results have shown, that the outcome of behavioural assays is likely to be variable, that it depends on the number of ants tested, that response to non-nestmates changes over time and that it changes in response to the experience of individual ants. A distributed system allows a colony to identify non-nestmates without requiring that all individuals have the same complete information and helps to facilitate the tracking of changes in cuticular hydrocarbon profiles, because only a subset of ants must respond to provide an adequate response.
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Affiliation(s)
- Fernando Esponda
- Department of Computer Science, Instituto Tecnológico Autónomo de México, México D.F. 01080, Mexico
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Gordon DM, Shehibo A, Tazebew A, Huddart MR, Kadir A, Allen N, Draper H, Kokeb M. Implementation of an in-patient pediatric mortality reduction intervention, Gondar University Hospital, Ethiopia. Public Health Action 2014; 4:265-70. [PMID: 26400707 DOI: 10.5588/pha.14.0077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/03/2014] [Indexed: 11/10/2022] Open
Abstract
SETTING Gondar University Hospital (GUH) is a resource-limited tertiary care hospital in northern Ethiopia. OBJECTIVE To evaluate the aggregate effect of care standardization, institutional guidelines, and simulation-based training on pediatric mortality at a resource-limited hospital. DESIGN Uncontrolled pre-post study. GUH in-patients aged from 30 days to 14 years were included in the program evaluation (baseline 11 September-18 November 2010; intervention 19 September-9 December 2011). Interns attached to the GUH pediatrics department from 6 September to 9 December 2011 were included in the training evaluation. Institution-specific management guidelines were prepared for choking, respiratory distress, dehydration, sepsis, congestive heart failure, coma, and seizure. Approval for the protocols was obtained from each pediatric faculty member. Interns received a 3.5 h simulation-based training in triage, procedural skills, and protocol usage. Primary outcome was overall deaths (%); secondary outcomes were deaths within 24 h of admission (%) and median pre/post-training emergency management test scores (%). RESULTS No difference in mortality (OR 0.72, 95%CI 0.40-1.29, P = 0.265) or first 24 h mortality (crude OR 0.97, 95%CI 0.37-2.55) was observed. Trainee examination scores improved from 33% to 74% (P < 0.001). CONCLUSION Combining care standardization, management protocols, and simulation-based training did not reduce mortality among pediatric in-patients. Focused, simulation-based training improved short-term test scores among interns.
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Affiliation(s)
- D M Gordon
- Texas Children's Hospital Global Health Corps, Baylor International Pediatric AIDS Initiative, Houston, Texas, USA
| | - A Shehibo
- Department of Pediatrics and Child Health, Gondar University Hospital, Gondar, Ethiopia
| | - A Tazebew
- Department of Pediatrics and Child Health, Gondar University Hospital, Gondar, Ethiopia
| | - M R Huddart
- Embrace, Yorkshire and Humber Infant and Childrens Transport Service, Sheffield, UK
| | - A Kadir
- Texas Children's Hospital Global Health Corps, Baylor International Pediatric AIDS Initiative, Houston, Texas, USA
| | - N Allen
- Yale University Global Health Leadership Institute, Eugene, Oregon, USA
| | - H Draper
- Texas Children's Hospital Global Health Corps, Baylor International Pediatric AIDS Initiative, Houston, Texas, USA
| | - M Kokeb
- Department of Pediatrics and Child Health, Gondar University Hospital, Gondar, Ethiopia
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Abstract
Networks of local interactions regulate biological systems. Ecological constraints set by resource distribution, operating costs, and the threat of rupture produce similar collective behavior in ants, cells, and gene transcription. Similar patterns of interaction, such as network motifs and feedback loops, are used in many natural collective processes, probably because they have evolved independently under similar pressures. Here I consider how three environmental constraints may shape the evolution of collective behavior: the patchiness of resources, the operating costs of maintaining the interaction network that produces collective behavior, and the threat of rupture of the network. The ants are a large and successful taxon that have evolved in very diverse environments. Examples from ants provide a starting point for examining more generally the fit between the particular pattern of interaction that regulates activity, and the environment in which it functions.
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Affiliation(s)
- Deborah M. Gordon
- Department of Biology, Stanford University, Stanford, California, United States of America
- * E-mail:
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38
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Gordon DM. Dependence of necrophoric response to oleic acid on social context in the ant,Pogonomyrmex badius. J Chem Ecol 2014; 9:105-11. [PMID: 24408623 DOI: 10.1007/bf00987774] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/1982] [Revised: 05/04/1982] [Indexed: 11/29/2022]
Abstract
The response of the southern harvester ant,Pogonomyrmex badius, to oleic acid was found to depend on social context. Social context was specified as the number of ants engaging in each of five categories of behavior. When a large percentage of the colony is doing midden work or nest maintenance, papers treated with oleic acid are taken to the midden, as previously reported. However, when a large percentage of the colony is foraging or convening, treated papers are taken into the nest as if they were food items.
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Affiliation(s)
- D M Gordon
- Department of Zoology, Duke University, 27706, Durham, North Carolina
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Pringle EG, Akçay E, Raab TK, Dirzo R, Gordon DM. Water stress strengthens mutualism among ants, trees, and scale insects. PLoS Biol 2013; 11:e1001705. [PMID: 24223521 PMCID: PMC3818173 DOI: 10.1371/journal.pbio.1001705] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/26/2013] [Indexed: 11/30/2022] Open
Abstract
Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.
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Affiliation(s)
- Elizabeth G. Pringle
- Department of Biology, Stanford University, Stanford, California, United States of America
- Michigan Society of Fellows, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- School of Natural Resources and Environment, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Erol Akçay
- Department of Biology, Stanford University, Stanford, California, United States of America
- National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, Tennessee, United States of America
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Ted K. Raab
- Carnegie Institution for Science, Stanford, California, United States of America
| | - Rodolfo Dirzo
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Deborah M. Gordon
- Department of Biology, Stanford University, Stanford, California, United States of America
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40
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Abstract
Argentine ants (Linepithema humile) live in groups of nests connected by trails to each other and to stable food sources. In a field study, we investigated whether some ants recruit directly from established, persistent trails to food sources, thus accelerating food collection. Our results indicate that Argentine ants recruit nestmates to food directly from persistent trails, and that the exponential increase in the arrival rate of ants at baits is faster than would be possible if recruited ants traveled from distant nests. Once ants find a new food source, they walk back and forth between the bait and sometimes share food by trophallaxis with nestmates on the trail. Recruiting ants from nearby persistent trails creates a dynamic circuit, like those found in other distributed systems, which facilitates a quick response to changes in available resources.
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Affiliation(s)
- Tatiana P Flanagan
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America.
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Pinter-Wollman N, Bala A, Merrell A, Queirolo J, Stumpe MC, Holmes S, Gordon DM. Harvester ants use interactions to regulate forager activation and availability. Anim Behav 2013; 86:197-207. [PMID: 24031094 PMCID: PMC3767282 DOI: 10.1016/j.anbehav.2013.05.012] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Social groups balance flexibility and robustness in their collective response to environmental changes using feedback between behavioural processes that operate at different timescales. Here we examine how behavioural processes operating at two timescales regulate the foraging activity of colonies of the harvester ant, Pogonomyrmex barbatus, allowing them to balance their response to food availability and predation. Previous work showed that the rate at which foragers return to the nest with food influences the rate at which foragers leave the nest. To investigate how interactions inside the nest link the rates of returning and outgoing foragers, we observed outgoing foragers inside the nest in field colonies using a novel observation method. We found that the interaction rate experienced by outgoing foragers inside the nest corresponded to forager return rate, and that the interactions of outgoing foragers were spatially clustered. Activation of a forager occurred on the timescale of seconds: a forager left the nest 3-8 s after a substantial increase in interactions with returning foragers. The availability of outgoing foragers to become activated was adjusted on the timescale of minutes: when forager return was interrupted for more than 4-5 min, available foragers waiting near the nest entrance went deeper into the nest. Thus, forager activation and forager availability both increased with the rate at which foragers returned to the nest. This process was checked by negative feedback between forager activation and forager availability. Regulation of foraging activation on the timescale of seconds provides flexibility in response to fluctuations in food abundance, whereas regulation of forager availability on the timescale of minutes provides robustness in response to sustained disturbance such as predation.
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Affiliation(s)
- Noa Pinter-Wollman
- Department of Biology, Stanford University, Stanford, CA, U.S.A
- Department of Statistics, Stanford University, Stanford, CA, U.S.A
| | - Ashwin Bala
- Department of Biology, Stanford University, Stanford, CA, U.S.A
| | - Andrew Merrell
- Department of Biology, Stanford University, Stanford, CA, U.S.A
| | - Jovel Queirolo
- Department of Biology, Stanford University, Stanford, CA, U.S.A
| | | | - Susan Holmes
- Department of Statistics, Stanford University, Stanford, CA, U.S.A
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Gordon DM, Pilko A, De Bortoli N, Ingram KK. Does an ecological advantage produce the asymmetric lineage ratio in a harvester ant population? Oecologia 2013; 173:849-57. [PMID: 23715745 PMCID: PMC3824609 DOI: 10.1007/s00442-013-2690-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 05/15/2013] [Indexed: 11/21/2022]
Abstract
In dependent-lineage harvester ant populations, two lineages interbreed but are genetically distinct. The offspring of a male and queen of the same lineage are female reproductives; the offspring of a male and queen of different lineages are workers. Geographic surveys have shown asymmetries in the ratio of the two lineages in many harvester ant populations, which may be maintained by an ecological advantage to one of the lineages. Using census data from a long-term study of a dependent-lineage population of the red harvester ant, Pogonomyrmex barbatus, we identified the lineage of 130 colonies sampled in 1997–1999, ranging in age from 1 to 19 years when collected, and 268 colonies sampled in 2010, ranging in age from 1 to 28 years when collected. The ratio of lineages in the study population is similar across an 11-year interval, 0.59 J2 in 1999 and 0.66 J2 in 2010. The rare lineage, J1, had a slightly but significantly higher number of mates of the opposite lineage than the common lineage, J2, and, using data from previous work on reproductive output, higher male production. Mature colonies of the two lineages did not differ in nest mound size, foraging activity, or the propensity to relocate their nests. There were no strong differences in the relative recruitment or survivorship of the two lineages. Our results show no ecological advantage for either lineage, indicating that differences between the lineages in sex ratio allocation may be sufficient to maintain the current asymmetry of the lineage ratio in this population.
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Affiliation(s)
- Deborah M Gordon
- Department of Biology, Stanford University, Stanford, CA, 94305-5020, USA,
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Abstract
Collective behavior is produced by interactions among individuals. Differences among groups in individual response to interactions can lead to ecologically important variation among groups in collective behavior. Here we examine variation among colonies in the foraging behavior of the harvester ant, Pogonomyrmex barbatus. Previous work shows how colonies regulate foraging in response to food availability and desiccation costs: the rate at which outgoing foragers leave the nest depends on the rate at which foragers return with food. To examine how colonies vary in response to humidity and in foraging rate, we performed field experiments that manipulated forager return rate in 94 trials with 17 colonies over 3 years. We found that the effect of returning foragers on the rate of outgoing foragers increases with humidity. There are consistent differences among colonies in foraging activity that persist from year to year.
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Affiliation(s)
- Deborah M Gordon
- Department of Biology, Stanford University, Stanford, California, United States of America.
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Gordon DM. The rewards of restraint in the collective regulation of foraging by harvester ant colonies. Nature 2013; 498:91-3. [PMID: 23676676 DOI: 10.1038/nature12137] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/02/2013] [Indexed: 11/09/2022]
Abstract
Collective behaviour, arising from local interactions, allows groups to respond to changing conditions. Long-term studies have shown that the traits of individual mammals and birds are associated with their reproductive success, but little is known about the evolutionary ecology of collective behaviour in natural populations. An ant colony operates without central control, regulating its activity through a network of local interactions. This work shows that variation among harvester ant (Pogonomyrmex barbatus) colonies in collective response to changing conditions is related to variation in colony lifetime reproductive success in the production of offspring colonies. Desiccation costs are high for harvester ants foraging in the desert. More successful colonies tend to forage less when conditions are dry, and show relatively stable foraging activity when conditions are more humid. Restraint from foraging does not compromise a colony's long-term survival; colonies that fail to forage at all on many days survive as long, over the colony's 20-30-year lifespan, as those that forage more regularly. Sensitivity to conditions in which to reduce foraging activity may be transmissible from parent to offspring colony. These results indicate that natural selection is shaping the collective behaviour that regulates foraging activity, and that the selection pressure, related to climate, may grow stronger if the current drought in their habitat persists.
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Affiliation(s)
- Deborah M Gordon
- Department of Biology, Stanford University, Stanford, California 94305-5020, USA.
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Ingram KK, Pilko A, Heer J, Gordon DM. Colony life history and lifetime reproductive success of red harvester ant colonies. J Anim Ecol 2013; 82:540-50. [DOI: 10.1111/1365-2656.12036] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 11/12/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Krista K. Ingram
- Department of Biology; Colgate University; Hamilton; NY; 13346; USA
| | - Anna Pilko
- Department of Biology; Stanford University; Stanford; CA; 94305-5020; USA
| | - Jeffrey Heer
- Department of Computer Science; Stanford University; Stanford; CA; 94305-5020; USA
| | - Deborah M. Gordon
- Department of Biology; Stanford University; Stanford; CA; 94305-5020; USA
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Greene MJ, Pinter-Wollman N, Gordon DM. Interactions with combined chemical cues inform harvester ant foragers' decisions to leave the nest in search of food. PLoS One 2013; 8:e52219. [PMID: 23308106 PMCID: PMC3540075 DOI: 10.1371/journal.pone.0052219] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 11/12/2012] [Indexed: 11/19/2022] Open
Abstract
Social insect colonies operate without central control or any global assessment of what needs to be done by workers. Colony organization arises from the responses of individuals to local cues. Red harvester ants (Pogonomyrmex barbatus) regulate foraging using interactions between returning and outgoing foragers. The rate at which foragers return with seeds, a measure of food availability, sets the rate at which outgoing foragers leave the nest on foraging trips. We used mimics to test whether outgoing foragers inside the nest respond to the odor of food, oleic acid, the odor of the forager itself, cuticular hydrocarbons, or a combination of both with increased foraging activity. We compared foraging activity, the rate at which foragers passed a line on a trail, before and after the addition of mimics. The combination of both odors, those of food and of foragers, is required to stimulate foraging. The addition of blank mimics, mimics coated with food odor alone, or mimics coated with forager odor alone did not increase foraging activity. We compared the rates at which foragers inside the nest interacted with other ants, blank mimics, and mimics coated with a combination of food and forager odor. Foragers inside the nest interacted more with mimics coated with combined forager/seed odors than with blank mimics, and these interactions had the same effect as those with other foragers. Outgoing foragers inside the nest entrance are stimulated to leave the nest in search of food by interacting with foragers returning with seeds. By using the combined odors of forager cuticular hydrocarbons and of seeds, the colony captures precise information, on the timescale of seconds, about the current availability of food.
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Affiliation(s)
- Michael J Greene
- Department of Integrative Biology, University of Colorado, Denver, CO, USA.
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Fitzgerald K, Heller N, Gordon DM. Modeling the spread of the Argentine ant into natural areas: Habitat suitability and spread from neighboring sites. Ecol Modell 2012. [DOI: 10.1016/j.ecolmodel.2012.07.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
The foraging behavior of the arboreal turtle ant, Cephalotes goniodontus, was studied in the tropical dry forest of western Mexico. The ants collected mostly plant-derived food, including nectar and fluids collected from the edges of wounds on leaves, as well as caterpillar frass and lichen. Foraging trails are on small pieces of ephemeral vegetation, and persist in exactly the same place for 4-8 days, indicating that food sources may be used until they are depleted. The species is polydomous, occupying many nests which are abandoned cavities or ends of broken branches in dead wood. Foraging trails extend from trees with nests to trees with food sources. Observations of marked individuals show that each trail is travelled by a distinct group of foragers. This makes the entire foraging circuit more resilient if a path becomes impassable, since foraging in one trail can continue while a different group of ants forms a new trail. The colony's trails move around the forest from month to month; from one year to the next, only one colony out of five was found in the same location. There is continual searching in the vicinity of trails: ants recruited to bait within 3 bifurcations of a main foraging trail within 4 hours. When bait was offered on one trail, to which ants recruited, foraging activity increased on a different trail, with no bait, connected to the same nest. This suggests that the allocation of foragers to different trails is regulated by interactions at the nest.
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Affiliation(s)
- Deborah M Gordon
- Department of Biology, Stanford University, Stanford, California, United States of America.
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Pinter-Wollman N, Gordon DM, Holmes S. Nest site and weather affect the personality of harvester ant colonies. Behav Ecol 2012; 23:1022-1029. [PMID: 22936841 PMCID: PMC3431114 DOI: 10.1093/beheco/ars066] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 01/10/2012] [Accepted: 03/19/2012] [Indexed: 11/14/2022] Open
Abstract
Environmental conditions and physical constraints both influence an animal's behavior. We investigate whether behavioral variation among colonies of the black harvester ant, Messor andrei, remains consistent across foraging and disturbance situations and ask whether consistent colony behavior is affected by nest site and weather. We examined variation among colonies in responsiveness to food baits and to disturbance, measured as a change in numbers of active ants, and in the speed with which colonies retrieved food and removed debris. Colonies differed consistently, across foraging and disturbance situations, in both responsiveness and speed. Increased activity in response to food was associated with a smaller decrease in response to alarm. Speed of retrieving food was correlated with speed of removing debris. In all colonies, speed was greater in dry conditions, reducing the amount of time ants spent outside the nest. While a colony occupied a certain nest site, its responsiveness was consistent in both foraging and disturbance situations, suggesting that nest structure influences colony personality.
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Affiliation(s)
- Noa Pinter-Wollman
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305-5020, USA
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