title: The origin and evolution of queen and fertility signals in Corbiculate bees.
abstract: BACKGROUND
  In social Hymenoptera (ants, bees and wasps), various chemical compounds present on the cuticle have been shown to act as fertility signals. In addition, specific queen-characteristic hydrocarbons have been implicated as sterility-inducing queen signals in ants, wasps and bumblebees. In Corbiculate bees, however, the chemical nature of queen-characteristic and fertility-linked compounds appears to be more diverse than in ants and wasps. Moreover, it remains unknown how queen signals evolved across this group and how they might have been co-opted from fertility signals in solitary ancestors.
  
  
  RESULTS
  Here, we perform a phylogenetic analysis of fertility-linked compounds across 16 species of solitary and eusocial bee species, comprising both literature data as well as new primary data from a key solitary outgroup species, the oil-collecting bee Centris analis, and the highly eusocial stingless bee Scaptotrigona depilis. Our results demonstrate the presence of fertility-linked compounds belonging to 12 different chemical classes. In addition, we find that some classes of compounds (linear and branched alkanes, alkenes, esters and fatty acids) were already present as fertility-linked signals in the solitary ancestors of Corbiculate bees, while others appear to be specific to certain species.
  
  
  CONCLUSIONS
  Overall, our results suggest that queen signals in Corbiculate bees are likely derived from ancestral fertility-linked compounds present in solitary bees that lacked reproductive castes. These original fertility-linked cues or signals could have been produced either as a by-product of ovarian activation or could have served other communicative purposes, such as in mate recognition or the regulation of egg-laying.
authors.affiliation: Department of Biology, Laboratory of Socioecology & Social Evolution, KU Leuven, Leuven, Belgium. ricardo.oliveira@bio.kuleuven.be.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Caliari Oliveira
authors.affiliation: Department of Biology, Laboratory of Socioecology & Social Evolution, KU Leuven, Leuven, Belgium. cintiaakemi.oi@bio.kuleuven.be.
authors.forename: Cintia Akemi
authors.initials: CA
authors.lastname: Oi
authors.affiliation: Department of Biology, Laboratory of Behavioral Ecology, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil. mauriciomnc21@gmail.com.
authors.forename: Mauricio Meirelles Castro
authors.initials: MM
authors.lastname: do Nascimento
authors.affiliation: Department of Biology, Laboratory of Behavioral Ecology, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil. ayrtonneto@usp.br.
authors.forename: Ayrton
authors.initials: A
authors.lastname: Vollet-Neto
authors.affiliation: Department of Entomology and Acarology, ESALQ, University of São Paulo, Piracicaba, Brazil. daalves@usp.br.
authors.forename: Denise Araujo
authors.initials: DA
authors.lastname: Alves
authors.affiliation: Department of Biology, Laboratory of Behavioral Ecology, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil. mclaudiac@bol.com.br.
authors.forename: Maria Claudia
authors.initials: MC
authors.lastname: Campos
authors.affiliation: Department of Biology, Laboratory of Behavioral Ecology, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil. fsnascim@usp.br.
authors.forename: Fabio
authors.initials: F
authors.lastname: Nascimento
authors.affiliation: Department of Biology, Laboratory of Socioecology & Social Evolution, KU Leuven, Leuven, Belgium. tom.wenseleers@bio.kuleuven.be.
authors.forename: Tom
authors.initials: T
authors.lastname: Wenseleers
mesh_terms: D000818:Animals; D001516:Bees / Q000737:chemistry* / Q000145:classification / Q000235:genetics* / Q000502:physiology; D005075:Biological Evolution; D005260:Female; D005298:Fertility; D006838:Hydrocarbons / Q000032:analysis; D008297:Male; D010058:Oviposition; D010802:Phylogeny; D012098:Reproduction; D012724:Sex Attractants / Q000737:chemistry*
chemical_list: D006838:Hydrocarbons; D012724:Sex Attractants