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Friston K, Friedman DA, Constant A, Knight VB, Fields C, Parr T, Campbell JO. A Variational Synthesis of Evolutionary and Developmental Dynamics. Entropy (Basel) 2023; 25:964. [PMID: 37509911 PMCID: PMC10378262 DOI: 10.3390/e25070964] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/12/2023] [Accepted: 06/15/2023] [Indexed: 07/30/2023]
Abstract
This paper introduces a variational formulation of natural selection, paying special attention to the nature of 'things' and the way that different 'kinds' of 'things' are individuated from-and influence-each other. We use the Bayesian mechanics of particular partitions to understand how slow phylogenetic processes constrain-and are constrained by-fast, phenotypic processes. The main result is a formulation of adaptive fitness as a path integral of phenotypic fitness. Paths of least action, at the phenotypic and phylogenetic scales, can then be read as inference and learning processes, respectively. In this view, a phenotype actively infers the state of its econiche under a generative model, whose parameters are learned via natural (Bayesian model) selection. The ensuing variational synthesis features some unexpected aspects. Perhaps the most notable is that it is not possible to describe or model a population of conspecifics per se. Rather, it is necessary to consider populations of distinct natural kinds that influence each other. This paper is limited to a description of the mathematical apparatus and accompanying ideas. Subsequent work will use these methods for simulations and numerical analyses-and identify points of contact with related mathematical formulations of evolution.
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Affiliation(s)
- Karl Friston
- Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, London WC1E 6AP, UK
| | - Daniel A Friedman
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
- Active Inference Institute, Davis, CA 95616, USA
| | - Axel Constant
- Theory and Method in Biosciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - V Bleu Knight
- Active Inference Institute, Davis, CA 95616, USA
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Chris Fields
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
| | - Thomas Parr
- Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, London WC1E 6AP, UK
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Friedman DA, Wexler JR, Alvarado S. Experimental Entomology in the Age of Video. J Vis Exp 2023. [PMID: 37602842 DOI: 10.3791/65002] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/22/2023] Open
Abstract
ARTICLES DISCUSSED Smodiš Škerl, M. I. Histology basics and cell death detection in honeybee tissue. Journal of Visualized Experiments. (185), e64141 (2022). Fine, J. D., Torres, K. M., Martin, J., Robinson, G. E. Assessing agrochemical risk to mated honey bee queens. Journal of Visualized Experiments. (169), e62316 (2022). Topitzhofer, E., Lucas, H., Carlson, E., Chakrabarti, P., Sagili, R. Collection and identification of pollen from honey bee colonies. Journal of Visualized Experiments. (167), e62064 (2022). Nogueira, B. R., de Oliveira, A. A., Silva, D., Pereira da Silva, J., Bueno, O. C. Collection and long-term maintenance of leaf-cutting ants (Atta) in laboratory conditions. Journal of Visualized Experiments. (186), e64154 (2022).
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Affiliation(s)
| | - Judith R Wexler
- Department of Ecology, Evolution, and Behavior, The Hebrew University in Jerusalem
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Friedman DA, Johnson BR, Linksvayer TA. Distributed physiology and the molecular basis of social life in eusocial insects. Horm Behav 2020; 122:104757. [PMID: 32305342 DOI: 10.1016/j.yhbeh.2020.104757] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/30/2020] [Accepted: 04/06/2020] [Indexed: 12/24/2022]
Abstract
The traditional focus of physiological and functional genomic research is on molecular processes that play out within a single multicellular organism. In the colonial (eusocial) insects such as ants, bees, and termites, molecular and behavioral responses of interacting nestmates are tightly linked, and key physiological processes are regulated at the scale of the colony. Such colony-level physiological processes regulate nestmate physiology in a distributed fashion, through various social communication mechanisms. As a result of physiological decentralization over evolutionary time, organismal mechanisms, for example related to pheromone detection, hormone signaling, and neural signaling pathways, are deployed in novel contexts to influence nestmate and colony traits. Here we explore how functional genomic, physiological, and behavioral studies can benefit from considering the traits of eusocial insects in this light. We highlight functional genomic work exploring how nestmate-level and colony-level traits arise and are influenced by interactions among physiologically-specialized nestmates of various developmental stages. We also consider similarities and differences between nestmate-level (organismal) and colony-level (superorganismal) physiological processes, and make specific hypotheses regarding the physiology of eusocial taxa. Integrating theoretical models of distributed systems with empirical functional genomics approaches will be useful in addressing fundamental questions related to the evolution of eusociality and collective behavior in natural systems.
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Affiliation(s)
- D A Friedman
- University of California, Davis, Department of Entomology, Davis, CA 95616, United States of America.
| | - B R Johnson
- University of California, Davis, Department of Entomology, Davis, CA 95616, United States of America
| | - T A Linksvayer
- University of Pennsylvania, Department of Biology, Pennsylvania, PA 19104, United States of America
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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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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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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
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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Marcus AW, Ebel ER, Friedman DA. Commentary: Portuguese crypto-Jews: the genetic heritage of a complex history. Front Genet 2015; 6:261. [PMID: 26300912 PMCID: PMC4528994 DOI: 10.3389/fgene.2015.00261] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/23/2015] [Indexed: 11/22/2022] Open
Affiliation(s)
| | - Emily R. Ebel
- Department of Biology, Stanford UniversityStanford, CA, USA
| | - Daniel A. Friedman
- Department of Biology, Stanford UniversityStanford, CA, USA
- *Correspondence: Daniel A. Friedman,
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