naturebriefs
10:42in productionCh. 1 · Discovered by Wallace/ 10:42 · ceiling 15 min
Fungi · Insects & invertebrates

Ophiocordyceps unilateralis

This fungus doesn’t just kill ants—it hijacks them, then fails more often than it succeeds.

Ophiocordyceps unilateralis is a tropical rainforest fungus that infects carpenter ants, manipulates them to bite leaf veins at precise heights and microclimates, then kills them and sprouts fruiting bodies from their heads. Discovered by Alfred Russel Wallace in 1859, it operates within tight thermal and hygrometric bounds—and is frequently derailed by hyperparasites.

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Chapters & takeaways4
  1. 0:54
    Discovered by Wallace

    Alfred Russel Wallace discovered it in 1859—long before 'behavioural manipulation' was a scientific concept.

  2. 2:22
    A climate-dependent killer

    It only works in tropical rainforests, where warmth and humidity hit narrow thresholds.

  3. 3:48
    The zombie ant protocol

    It compels carpenter ants to climb, bite, and die on leaf veins—then sprouts from their heads.

  4. 5:23
    A fragile reproductive strategy

    Its fruiting bodies rupture from ant heads in 4–10 days—but hyperparasites destroy most spores.

Worth your time?

Yes. See the whole thing.

4/ 5
What works
  • selects precise microclimates (20–30°C, 94–95% RH)
  • fixes hosts to leaf veins for optimal spore dispersal
  • reveals extended fungal phenotypes in real time
What does not
  • control non-Camponotini ants
  • thrive outside tropical rainforests
  • achieve high spore viability
See it if
  • field mycologists
  • behavioural ecologists
  • rainforest naturalists
Skip it if
  • temperate-zone foragers
  • lab-only microbiologists
  • conservation planners without microclimate data
The written brief1 min read

What the species is and where it came from

Ophiocordyceps unilateralis is an insect-pathogenic fungus discovered by Alfred Russel Wallace in 1859. It belongs to Hypocreales and forms a species complex with host-specific clades.

How it works, in terms someone would actually use

It infects carpenter ants in tropical rainforests. The ant climbs down, bites into a leaf vein at ~25 cm height, and dies. Fruiting bodies grow from its head in 4–10 days.

What it gets right

It selects precise microclimates: 20–30°C and 94–95% relative humidity. It fixes the ant to leaf veins—not stems or soil—to optimise spore dispersal.

What it does not

It does not control all ants. It targets only Camponotini—especially carpenter ants. It cannot sustain outbreaks: hyperparasitism limits spore viability to ~6.5%.

What it changed

It revealed that fungi can extend their phenotype into host behaviour. Alfred Russel Wallace documented it in 1859. Fossil evidence shows this ant-manipulating behaviour has existed for at least 48 million years.

Who it is for, and who it is not

It is for field mycologists, behavioural ecologists, and rainforest naturalists. It is not for temperate-zone foragers, lab-only microbiologists, or conservation planners lacking microclimate data.

Is it worth your time

Yes—if you want to see fungal manipulation of behaviour in situ. It is visible, repeatable, and geographically concentrated—but only in warm, humid rainforest understory.

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