title: A Brazilian social bee must cultivate fungus to survive.
abstract: The nests of social insects provide suitable microenvironments for many microorganisms as they offer stable environmental conditions and a rich source of food [1-4]. Microorganisms in turn may provide several benefits to their hosts, such as nutrients and protection against pathogens [1, 4-6]. Several examples of symbiosis between social insects and microorganisms have been found in ants and termites. These symbioses have driven the evolution of complex behaviors and nest structures associated with the culturing of the symbiotic microorganisms [5, 7, 8]. However, while much is known about these relationships in many species of ants and termites, symbiotic relationships between microorganisms and social bees have been poorly explored [3, 4, 9, 10]. Here, we report the first case of an obligatory relationship between the Brazilian stingless bee Scaptotrigona depilis and a fungus of the genus Monascus (Ascomycotina). Fungal mycelia growing on the provisioned food inside the brood cell are eaten by the larva. Larvae reared in vitro on sterilized larval food supplemented with fungal mycelia had a much higher survival rate (76%) compared to larvae reared under identical conditions but without fungal mycelia (8% survival). The fungus was found to originate from the material from which the brood cells are made. Since the bees recycle and transport this material between nests, fungus would be transferred to newly built cells and also to newly founded nests. This is the first report of a fungus cultivation mutualism in a social bee.
authors.affiliation: Embrapa Amazônia Oriental, Brazilian Agricultural Research Corporation, Tv. Dr. Enéas Pinheiro, 66095-100 Belém-PA, Brazil; Embrapa Meio Ambiente, Brazilian Agricultural Research Corporation, Rodovia SP-340, Km 127.5, 13820-000 Jaguariúna-SP, Brazil; Faculty of Philosophy, Sciences and Languages of Ribeirão Preto, University of São Paulo, 3900 Av. Bandeirantes, 14040-901 Ribeirão Preto-SP, Brazil. Electronic address: cristiano.menezes@embrapa.br.
authors.forename: Cristiano
authors.initials: C
authors.lastname: Menezes
authors.affiliation: Faculty of Philosophy, Sciences and Languages of Ribeirão Preto, University of São Paulo, 3900 Av. Bandeirantes, 14040-901 Ribeirão Preto-SP, Brazil.
authors.forename: Ayrton
authors.initials: A
authors.lastname: Vollet-Neto
authors.affiliation: Chemistry Institute, University of Campinas, R. Josué de Castro, 13083-970 Campinas, Brazil.
authors.forename: Anita Jocelyne
authors.initials: AJ
authors.lastname: Marsaioli
authors.affiliation: Chemistry Institute, University of Campinas, R. Josué de Castro, 13083-970 Campinas, Brazil.
authors.forename: Davila
authors.initials: D
authors.lastname: Zampieri
authors.affiliation: Laboratory of Biotechnology, School of Applied Sciences, University of Campinas, 1300 R. Pedro Zaccaria, 13484-350 Limeira-SP, Brazil.
authors.forename: Isabela Cardoso
authors.initials: IC
authors.lastname: Fontoura
authors.affiliation: Laboratory of Biotechnology, School of Applied Sciences, University of Campinas, 1300 R. Pedro Zaccaria, 13484-350 Limeira-SP, Brazil.
authors.forename: Augusto Ducati
authors.initials: AD
authors.lastname: Luchessi
authors.affiliation: Faculty of Philosophy, Sciences and Languages of Ribeirão Preto, University of São Paulo, 3900 Av. Bandeirantes, 14040-901 Ribeirão Preto-SP, Brazil; Vale Institute of Technology, 955 R. Boaventura da Silva, 66055-090 Belém-PA, Brazil.
authors.forename: Vera Lucia
authors.initials: VL
authors.lastname: Imperatriz-Fonseca
mesh_terms: D000383:Agriculture; D000818:Animals; D001516:Bees / Q000382:microbiology*; D001522:Behavior, Animal / Q000502:physiology; D005075:Biological Evolution; D001938:Brazil; D005658:Fungi / Q000502:physiology*; D007814:Larva / Q000382:microbiology; D013559:Symbiosis / Q000502:physiology
keywords: Meliponini; fungus farming; stingless bees; symbiosis