naturebriefs
9:16in productionCh. 1 · The Raid/ 9:16 · ceiling 15 min
Insects & invertebrates · Systems

Army ant

They don’t build nests. They don’t stay still. They don’t share queens. And they eat everything in their path—by the million.

Army ants are a functional category—not a taxon—defined by nomadism, mass raiding, and monogynous, wingless queens. Genetic evidence from 2003 shows some lineages share deep ancestry; others converged. Their raids drive ecosystem dynamics across tropical forests. They offer no compromise: no stillness, no shared queens, no permanent home.

Insects & invertebratesSystemsAdaptationBiodiversityEcologyAdaptation across the network →
Chapters & takeaways6
  1. 0:38
    The Raid

    Raids are not hunting parties—they’re moving walls of ants that flood the forest floor and consume every arthropod in their path.

  2. 1:34
    No Nest, No Rest

    No nest means no home base—just a living bivouac of linked bodies, rebuilt daily as the colony marches.

  3. 2:43
    Two Origins, One Behaviour

    Some army ants share DNA from before the continents split—but others reinvented the same brutal lifestyle from scratch.

  4. 3:59
    One Queen, No Compromise

    One queen. Wingless. Immense. Monogynous colonies eliminate internal conflict—and make fission the only way to grow.

  5. 5:00
    Bodies Built for War and Sex

    Soldiers have mandibles that scale with age. Males look like wasps—and carry genitalia found nowhere else in Formicidae.

  6. 6:04
    Legionary Behaviour Is Not One Thing

    Legionary behaviour is not a single adaptation—it’s a syndrome repeated across evolutionary lineages, sometimes by chance, sometimes by descent.

Worth your time?

Yes. See the whole thing.

4.5/ 5
What works
  • collective predation via density and coordination
  • reproductive strategy via one wingless, hyper-fecund queen
  • symbiosis via support for hundreds of specialist followers
What does not
  • establish territory
  • defend fixed resources
  • recruit individually
  • use pheromone trails like other ants
See it if
  • field ecologists
  • tropical biologists
  • behavioural entomologists
Skip it if
  • gardeners
  • pest controllers
  • anyone seeking a model for human organisation
The written brief2 min read

What the species is and where it came from

Army ants are not a single species but over 200 species across multiple ant subfamilies—including Ecitoninae, Dorylinae, Aenictinae, Leptanillinae, Ponerinae, Amblyoponinae and Myrmicinae—unified by legionary behaviour. Some share a ~100-million-year-old Gondwanan ancestor; others evolved the same traits independently.

How it works, in terms someone would actually use

Army ants forage in aggressive, simultaneous predatory groups called ‘raids’. They do not build permanent nests. Colonies cycle between nomadic phases—moving daily—and stationary phases for pupation and egg-laying. Each colony has exactly one wingless, hyper-fecund queen.

What it gets right

They get collective predation right: raids overwhelm prey through density and coordination, not individual speed or venom. They get reproductive strategy right: one queen, wingless, massively fecund, producing millions of eggs per month. They get symbiosis right: their raids support hundreds of specialist followers, from birds to mites.

What it does not

Army ants do not establish territory. They do not defend fixed resources. They do not recruit individually or use pheromone trails like other ants. They do not persist in temperate or arid zones. They do not coexist with multiple queens.

What it changed

Army ants redefined ant ecology by proving that obligate nomadism and mass raiding can sustain colonies at enormous scale. Their genetic history forced a rethink of convergent evolution: some lineages share a Gondwanan ancestor from ~100 million years ago; others evolved the same behaviour independently.

Who it is for, and who it is not

It is for field ecologists, tropical biologists, and behavioural entomologists who work in Neotropical and Afrotropical forests. It is not for gardeners, pest controllers, or anyone seeking a model for human organisation—it operates on no plan, no leader, no memory.

Is it worth your time

Yes—if you are in tropical forest understory and want to witness a mobile, self-organising predator that reshapes local food webs daily. No—if you expect to find them in soil, leaf litter, or open savanna, or if you need predictable timing: raids shift location without warning, and bivouacs last only hours to days.

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CicadaCicadas are globally distributed Hemipteran insects with fossil origins in the Upper Permian. They live in trees, feed on xylem sap, and lay eggs in bark slits. Most produce loud songs via tymbals. Magicicada species emerge synchronously every 13 or 17 years—likely to reduce predation. Their forewings are superhydrophobic and bactericidal due to nanoscale spikes.
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