title: Ant species identity mediates reproductive traits and allocation in an ant-garden bromeliad.
abstract: OBJECTIVE
  Determining the sources of variation in floral morphology is crucial to understanding the mechanisms underlying Angiosperm evolution. The selection of floral and reproductive traits is influenced by the plant's abiotic environment, florivores and pollinators. However, evidence that variations in floral traits result from mutualistic interactions with insects other than pollinators is lacking in the published literature and has rarely been investigated. We aimed to determine whether the association with either Camponotus femoratus or Pachycondyla goeldii (both involved in seed dispersal and plant protection) mediates the reproductive traits and allocation of Aechmea mertensii, an obligatory ant-garden tank-bromeliad, differently.
  
  
  METHODS
  Floral and reproductive traits were compared between the two A. mertensii ant-gardens. The nitrogen flux from the ants to the bromeliads was investigated through experimental enrichments with stable isotopes ((15)N).
  
  
  RESULTS
  Camponotus femoratus-associated bromeliads produced inflorescences up to four times longer than did P. goeldii-associated bromeliads. Also, the numbers of flowers and fruits were close to four times higher, and the number of seeds and their mass per fruit were close to 1·5 times higher in C. femoratus than in P. goeldii-associated bromeliads. Furthermore, the (15)N-enrichment experiment showed that C. femoratus-associated bromeliads received more nitrogen from ants than did P. goeldii-associated bromeliads, with subsequent positive repercussions on floral development. Greater benefits were conferred to A. mertensii by the association with C. femoratus compared with P. goeldii ants.
  
  
  CONCLUSIONS
  We show for the first time that mutualistic associations with ants can result in an enhanced reproductive allocation for the bromeliad A. mertensii. Nevertheless, the strength and direction of the selection of floral and fruit traits change based on the ant species and were not related to light exposure. The different activities and ecological preferences of the ants may play a contrasting role in shaping plant evolution and speciation.
authors: CNRS, UMR Ecologie des Forêts de Guyane (UMR-CNRS 8172), Campus Agronomique, F-97379 Kourou cedex, France.
authors: Céline
authors: C
authors: Leroy
authors: Bruno
authors: B
authors: Corbara
authors: Laurent
authors: L
authors: Pélozuelo
authors: Jean-François
authors: JF
authors: Carrias
authors: Alain
authors: A
authors: Dejean
authors: Régis
authors: R
authors: Céréghino
mesh_terms: D000818:Animals; D001000:Ants / Q000502:physiology*; D005075:Biological Evolution; D031229:Bromeliaceae / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D035264:Flowers / Q000033:anatomy & histology; D005616:French Guiana; D005638:Fruit / Q000254:growth & development; D049810:Genetic Speciation; D009584:Nitrogen / Q000378:metabolism; D054817:Pollination; D058614:Seed Dispersal; D012639:Seeds / Q000254:growth & development
chemical_list: D009584:Nitrogen