Endoparasitic ascomycete that infects carpenter ants (Camponotus spp.). Internally, white mycelium proliferates through host tissues while leaving vital organs functional. Upon host death, a single dark-brown stromatal stalk (5–20 mm) erupts from the ant’s pronotum, ending in a clavate, velvety fertile head bearing asexual Hirsutella-type conidiophores followed by perithecial (sexual) maturation. Perithecia flask-shaped, embedded; ascospores filiform, 100–130 × 3 µm, fragmenting into secondary spores. Fruiting body covered by orange–rust patches of parasitic hyperfungi (Calonectria sp.) late in decay. Characteristic “death grip” of host ant on abaxial leaf veins or twigs at 25–35 cm above ground optimises humidity for fungal development.
5–20 mm; fertile head Ø 2–3 mm
≈ 20–40 mg
Stromata viable 3–6 weeks; mycelium persists indeterminately in cadaver
Fungi do not apply
Fungi do not apply
≈ 10–14 days post-host death (≥ 95 % RH)
Peak May–July (early wet season) in Costa Rica
Endoparasitic ascomycete that infects carpenter ants (Camponotus spp.). Internally, white mycelium proliferates through host tissues while leaving vital organs functional. Upon host death, a single dark-brown stromatal stalk (5–20 mm) erupts from the ant’s pronotum, ending in a clavate, velvety fertile head bearing asexual Hirsutella-type conidiophores followed by perithecial (sexual) maturation. Perithecia flask-shaped, embedded; ascospores filiform, 100–130 × 3 µm, fragmenting into secondary spores. Fruiting body covered by orange–rust patches of parasitic hyperfungi (Calonectria sp.) late in decay. Characteristic “death grip” of host ant on abaxial leaf veins or twigs at 25–35 cm above ground optimises humidity for fungal development.
Humid understory of lowland tropical rain forest (0–1 000 m) on both Pacific and Caribbean slopes; requires closed canopy (RH > 90 %, T 22–28 °C) and abundant Camponotus host colonies
Obligate entomopathogen/parasite; recycles nutrients via cadaver decomposition and influences ant population dynamics.
Developmental Behaviour & Manipulation
Infection route: airborne ascospores adhere to ant cuticle, germinate, penetrate exoskeleton.
Host manipulation: 8–10 days post-infection, ant leaves trail, climbs vegetation, bites vein (“death grip”) then dies; fungus sporulates.
Social context: infected ants are removed by nest-mates if detected; parasite counters by manipulating individual to die away from colony.
Chemical secretions cause ants to climb exactly 24–29 cm—optimal for spore release and germination.
Genome encodes expanded repertoire of neuroactive secondary metabolites (e.g., sphingosines).
Hyperparasite Calonectria spp. often overgrows senescent stromata, creating “fungus on a fungus.”
Used by bio-robotics researchers as model of behaviour-manipulating parasites.
Time-lapse videos from Corcovado show stroma elongating 5 mm in 12 h under night-time humidity spikes.
Native
Decreasing
