Evolution of cold-tolerant fungal symbionts permits winter fungiculture by leafcutter ants at the northern frontier of a tropical ant-fungus symbiosis. - Mueller UG; Mikheyev AS; Hong E; Sen R; Warren DL; Solomon SE; Ishak HD; Cooper M; Miller JL; Shaffer KA; Juenger TE (Proceedings of the National Academy of Sciences of the United States of America, 2011)