The coevolution of fungus-ant agriculture.

Fungus-farming ants cultivate multiple lineages of fungi for food, but, because fungal cultivar relationships are largely unresolved, the history of fungus-ant coevolution remains poorly known. We designed probes targeting >2000 gene regions to generate a dated evolutionary tree for 475 fungi and combined it with a similarly generated tree for 276 ants. We found that fungus-ant agriculture originated ~66 million years ago when the end-of-Cretaceous asteroid impact temporarily interrupted photosynthesis, causing global mass extinctions but favoring the proliferation of fungi. Subsequently, ~27 million years ago, one ancestral fungal cultivar population became domesticated, i.e., obligately mutualistic, when seasonally dry habitats expanded in South America, likely isolating the cultivar population from its free-living, wet forest–dwelling conspecifics. By revealing these and other major transitions in fungus-ant coevolution, our results clarify the historical processes that shaped a model system for nonhuman agriculture. Humans have developed extensive agricultural relationships with many other species, including both plants and animals, but we are not the only species to do so. Ants are known to cultivate many lineages of fungus for their own consumption, a relationship that takes different forms. Schulz . characterized the coevolution between these groups, identifying several key transitions that have led to the complexity of their modern relationship, including its emergence after the end-Cretaceous extinction. —Sacha Vignieri

Funder

Funder name	Awards
National Science Foundation, United Kingdom	DEB 1927161 - DEB 1927224 - DEB 1927411 - DEB 1927155 - DEB 1654829 - DEB 1456964 - DEB 1740940 - CAREER DEB 1943626
Louisiana Board of Regents, United States	RCS grant LEQSF(2016-19)-RD-A-01
Sistema Nacional de Investigación, Secretaría Nacional de Ciencia, Tecnología e Innovación	No. 064-2023
University of Maryland, United States / Smithsonian Institution, United States	Seed Grant
Smithsonian Institution, United States	Peter S. Buck Predoctoral Fellowship Program - NMNH Biological Diversity of the Guaiana Shield Program
Cosmos Club Foundation, United States
Explorers Club, United States
Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil	Ggrant 2019/03746-0 - Grant 2021/10639-5 - Grant 2019/22329-0 - Grant 2022/14456-5
Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil	Grant 304628/2020-4
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil	Grant no. 88887.468939/2019-00 - Grant no. 88887.571230/2020–00 - Grant BEX2145/15-4
Calleva Foundation, United Kingdom	Plant and Fungal Trees of Life project
Carl-Zeiss-Stiftung, Germany