identifier: traitmech:000062
label: swarming motility
definition: A flagella-dependent, multicellular surface motility in which cells move
  rapidly and coordinately across a surface, typically accompanied by hyperflagellation
  and secretion of a wetting surfactant.
definition_source: DOI:10.1038/nrmicro2405
trait_category: MORPHOLOGY
term_kind: CLASS
mapping_status: REVIEWED
parent_traits:
- METPO:1000702
synonyms:
- synonym_text: swarming
  synonym_type: RELATED_SYNONYM
  source: DOI:10.1038/nrmicro2405
evidence:
- reference: DOI:10.1038/nrmicro2405
  notes: Kearns, "A field guide to bacterial swarming motility", defines swarming
    via increased flagella per cell, surfactant secretion, and movement in multicellular
    groups.
- reference: DOI:10.1146/annurev.micro.57.030502.091014
  notes: Harshey, "Bacterial motility on a surface", places swarming among the surface-motility
    modes of bacteria.
canonical_examples:
- taxon_id: NCBITaxon:584
  taxon_label: Proteus mirabilis
  note: "Historical/diagnostic swarming model (bulls-eye colonies; hyper-flagellated swarmer cells)."
  reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10671106/
causal_graphs:
- graph_id: swarming_hyperflagellation_surfactant
  title: Swarming motility via hyperflagellation and surfactant secretion
  description: Evidence-backed causal sketch linking flagellar hyperflagellation and
    wetting-surfactant secretion to multicellular surface swarming.
  nodes:
  - node_id: swarming_trait
    label: swarming motility
    node_type: TRAIT
    grounding: traitmech:000062
    description: Flagella-dependent multicellular surface motility.
  - node_id: bacterial_flagellum
    label: bacterial-type flagellum
    node_type: CELLULAR_LOCALIZATION
    grounding: GO:0009288
    description: Helical proteinaceous locomotory organelle (hyperflagellation under
      swarming).
  - node_id: surfactant
    label: wetting surfactant
    node_type: CHEMICAL
    description: Secreted surfactant lowering surface tension to support spreading.
  - node_id: flagellar_motility
    label: bacterial flagellum-dependent cell motility
    node_type: BIOLOGICAL_PROCESS
    grounding: GO:0071973
    description: Swimming/swarming motility driven by flagellar rotation.
  - node_id: quorum_sensing
    label: quorum sensing
    node_type: BIOLOGICAL_PROCESS
    description: Cell-density signaling that regulates production of swarming-associated
      wetting surfactants.
    grounding: GO:0009372
  - node_id: swarm_expansion
    label: swarm expansion
    node_type: BIOLOGICAL_PROCESS
    description: Outward dendritic spreading of a multicellular swarm across a surface.
  edges:
  - subject: bacterial_flagellum
    predicate: enables
    object: swarming_trait
    description: Hyperflagellation provides the propulsive machinery for swarming.
    evidence:
    - reference: DOI:10.1038/nrmicro2405
      notes: Kearns defines swarming via increased flagella per cell.
    predicate_id: RO:0002327
  - subject: surfactant
    predicate: enables
    object: swarming_trait
    description: Secreted wetting surfactant supports multicellular surface spreading.
    evidence:
    - reference: DOI:10.1038/nrmicro2405
      notes: Kearns defines swarming via surfactant secretion accompanying hyperflagellation.
    predicate_id: RO:0002327
  - subject: swarming_trait
    predicate: participates in
    object: flagellar_motility
    description: Swarming is a flagella-driven surface-motility mode.
    evidence:
    - reference: DOI:10.1146/annurev.micro.57.030502.091014
      notes: Harshey places swarming among the surface-motility modes of bacteria.
    predicate_id: biolink:participates_in
  - subject: quorum_sensing
    predicate: positively regulates
    object: surfactant
    description: Quorum sensing controls production of wetting surfactants (HAAs/rhamnolipids)
      required for swarm development.
    evidence:
    - reference: DOI:10.1063/5.0128140
      notes: 'Bru et al. 2023 review: QS regulates HAA and rhamnolipid production
        needed for swarm development.'
  - subject: surfactant
    predicate: positively regulates
    object: swarm_expansion
    description: Secreted wetting surfactants are required for normal swarm expansion
      and tendril formation; surfactant-deficient mutants fail to expand.
    evidence:
    - reference: DOI:10.1063/5.0128140
      notes: 'Bru et al. 2023: mutants defective in rhamnolipid production are deficient
        in swarm expansion and fail to form tendrils.'
  - subject: bacterial_flagellum
    predicate: positively regulates
    object: swarm_expansion
    description: Flagellar activity, alongside surfactant production, is essential
      for dendritic swarm expansion.
    evidence:
    - reference: DOI:10.1063/5.0128140
      notes: 'Bru et al. 2023: two activities are essential for forming dendritic
        swarms - surfactant production and flagellar activity.'
curation_history:
- timestamp: '2026-06-03T00:00:00Z'
  curator: claude
  action: PROPOSED_FROM_RESEARCH
  changes: Proposed candidate MORPHOLOGY/motility trait (swarming motility) under
    the existing motile class (METPO:1000702).
  llm_assisted: true
- timestamp: '2026-06-09T15:00:00Z'
  curator: claude
  action: CURATED_CAUSAL_GRAPH
  changes: Added evidence-backed causal graph (hyperflagellation + surfactant swarming)
    with GO node groundings and RO/biolink predicate groundings; promoted PROPOSED
    to REVIEWED.
  llm_assisted: true
- timestamp: '2026-06-23T00:00:00Z'
  curator: claude
  action: ENRICH_CAUSAL_GRAPH
  changes: Added 3 evidence-backed generic edges (2 new nodes) from the deep-research
    report.
  llm_assisted: true
- timestamp: '2026-06-24T17:23:34Z'
  curator: claude
  action: GROUND_CAUSAL_NODES
  changes: Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv
    (GO:0009372×1).
  llm_assisted: true