2009/07/23 by Sandra B. Andersen, Sandra B. Andersen, Sylvia Gerritsma +10 · 244 citations
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #ANT #Adaptation (eye) #Arboreal locomotion #Biology #Botany #Ecology #Entomopathogenic Microorganisms in Pest Control #Fire ant #Fungus #Gene #Genetics #Habitat #Host (biology) #Hymenoptera #Insect and Arachnid Ecology and Behavior #Insect symbiosis and bacterial influences #Parasite hosting #Phenotype #Zoology
paper · open access · doi:10.1086/603640
published in The American Naturalist 174(3), 424-433 (University of Chicago Press)
openalex publication_date 2009/07/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/03
Specialized parasites are expected to express complex adaptations to their hosts. Manipulation of host behavior is such an adaptation. We studied the fungus Ophiocordyceps unilateralis, a locally specialized parasite of arboreal Camponotus leonardi ants. Ant-infecting Ophiocordyceps are known to make hosts bite onto vegetation before killing them. We show that this represents a fine-tuned fungal adaptation: an extended phenotype. Dead ants were found under leaves, attached by their mandibles, on the northern side of saplings approximately 25 cm above the soil, where temperature and humidity conditions were optimal for fungal growth. Experimental relocation confirmed that parasite fitness was lower outside this manipulative zone. Host resources were rapidly colonized and further secured by extensive internal structuring. Nutritional composition analysis indicated that such structuring allows the parasite to produce a large fruiting body for spore production. Our findings suggest that the osmotrophic lifestyle of fungi may have facilitated novel exploitation strategies.