title: Diploid Male Production Results in Queen Death in the Stingless Bee Scaptotrigona depilis.
abstract: As in most Hymenoptera, the eusocial stingless bees (Meliponini) have a complementary sex determination (CSD) system. When a queen makes a "matched mating" with a male that shares a CSD allele with her, half of their diploid offspring are diploid males rather than females. Matched mating imposes a cost, since diploid male production reduces the colony workforce. Hence, adaptations preventing the occurrence or attenuating its effects are likely to arise. Here we provide clear evidence that in the stingless bee Scaptotrigona depilis, the emergence of diploid males induces queen death, and this usually occurs within 10-20 days of the emergence of diploid male offspring from their pupae. Queens that have not made a matched mating die when introduced into a colony in which diploid males are emerging. This shows that the adult diploid males, and not the queen that has made a matched mating herself, are the proximate cause of queen death. Analysis of the cuticular hydrocarbon profiles of adult haploid and diploid males shows six compounds with significant differences. Moreover, the diploid and haploid males only acquire distinct cuticular hydrocarbon profiles 10 days after emergence. Our data shows that the timing of queen death occurs when the cuticular hydrocarbons of haploid and diploid males differ significantly, suggesting that these chemical differences could be used as cues or signals to trigger queen death.
authors.affiliation: Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, SP, Brazil. ayrtonvollet@gmail.com.
authors.forename: Ayrton
authors.identifier: http://orcid.org/0000-0003-0303-2908
authors.initials: A
authors.lastname: Vollet-Neto
authors.affiliation: Laboratory of Socioecology and Social Evolution, Zoological Institute, KU Leuven, Leuven, Belgium.
authors.forename: Ricardo C
authors.initials: RC
authors.lastname: Oliveira
authors.affiliation: Laboratory of Socioecology and Social Evolution, Zoological Institute, KU Leuven, Leuven, Belgium.
authors.forename: Sharon
authors.initials: S
authors.lastname: Schillewaert
authors.affiliation: Departamento de Entomologia e Acarologia, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, Piracicaba, SP, Brazil.
authors.forename: Denise A
authors.initials: DA
authors.lastname: Alves
authors.affiliation: Laboratory of Socioecology and Social Evolution, Zoological Institute, KU Leuven, Leuven, Belgium.
authors.forename: Tom
authors.initials: T
authors.lastname: Wenseleers
authors.affiliation: Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Fabio S
authors.initials: FS
authors.lastname: Nascimento
authors.affiliation: Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, SP, Brazil.|Instituto Tecnológico Vale, Belém, PA, Brazil.
authors.forename: Vera L
authors.initials: VL
authors.lastname: Imperatriz-Fonseca
authors.affiliation: Laboratory of Apiculture & Social Insects (LASI), School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK.
authors.forename: Francis L W
authors.initials: FLW
authors.lastname: Ratnieks
mesh_terms: D000818:Animals; D001516:Bees / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D004247:DNA / Q000032:analysis; D004171:Diploidy; D005260:Female; D006838:Hydrocarbons / Q000737:chemistry / Q000378:metabolism; D007814:Larva / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D008297:Male; D012098:Reproduction; D012726:Sexual Behavior, Animal
chemical_list: D006838:Hydrocarbons; D004247:DNA
keywords: Chemical recognition; Diploid male load; Queen execution; Sex determination