title: Multi-locus phylogenies of the genus Barteria (Passifloraceae) portray complex patterns in the evolution of myrmecophytism.
abstract: The four species of the central African genus Barteria show variation in habitat and in degree of association with ants. Whereas B. solida, restricted to submontane forests, attracts opportunistic ants to extrafloral nectar, the three other species, found in lowland rainforests (B. fistulosa, B. dewevrei) and in littoral scrub (B. nigritana), possess stem domatia of varying shapes and degrees of specialisation, hosting either non-specific arboreal ants (B. nigritana, some B. dewevrei) or two large species of ants of the genus Tetraponera Smith, 1852 that are specific to some species of Barteria (B. fistulosa, some B. dewevrei). We aimed to investigate whether this variation represents an evolutionary trend toward increasing specialisation of mutualism or the reduction or loss of myrmecophytic traits. For this, we determined phylogenetic relationships within the genus using DNA sequences (primarily nuclear ITS) and microsatellite genotypes (11 loci) on a large sample of individuals, mostly from Cameroon and Gabon. The two types of markers support an initial dichotomy that groups B. dewevrei with B. nigritana and B. fistulosa with B. solida respectively. Within these pairs, species do not appear reciprocally monophyletic. At microsatellite loci, B. nigritana forms a clade embedded within B. dewevrei; and within both B. solida and B. fistulosa, geographical populations show levels of differentiation similar to that observed between populations of B. solida and B. fistulosa. Geographic distance alone does not account for genetic differentiation between species, which indicates reproductive isolation. Divergence in each of the two pairs implies evolutionary transitions in habitat and in myrmecophytism. Specialised mutualism with specific ant species of the genus Tetraponera has been lost in species found in more marginal habitats.
authors.affiliation: Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, Université Montpellier 2, 1919 route de Mende, 34293 Montpellier Cedex 5, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Peccoud
authors.forename: Finn
authors.initials: F
authors.lastname: Piatscheck
authors.forename: Roxana
authors.initials: R
authors.lastname: Yockteng
authors.forename: Marjorie
authors.initials: M
authors.lastname: Garcia
authors.forename: Mathieu
authors.initials: M
authors.lastname: Sauve
authors.forename: Champlain
authors.initials: C
authors.lastname: Djiéto-Lordon
authors.forename: David J
authors.initials: DJ
authors.lastname: Harris
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Wieringa
authors.forename: Frans J
authors.initials: FJ
authors.lastname: Breteler
authors.forename: Céline
authors.initials: C
authors.lastname: Born
authors.forename: Doyle
authors.initials: D
authors.lastname: McKey
authors.forename: Rumsaïs
authors.initials: R
authors.lastname: Blatrix
mesh_terms: D000818:Animals; D001000:Ants / Q000502:physiology*; D001483:Base Sequence; D001499:Bayes Theorem; D002163:Cameroon; D017931:DNA Primers / Q000235:genetics; D017753:Ecosystem; D005681:Gabon; D014644:Genetic Variation; D016013:Likelihood Functions; D018895:Microsatellite Repeats / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D031683:Passifloraceae / Q000235:genetics* / Q000502:physiology*; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013559:Symbiosis / Q000235:genetics*
chemical_list: D017931:DNA Primers