title: Vertebrate bacterial gut diversity: size also matters.
abstract: BACKGROUND
  One of the central issues in microbial ecology is to understand the parameters that drive diversity. Among these parameters, size has often been considered to be the main driver in many different ecosystems. Surprisingly, the influence of size on gut microbial diversity has not yet been investigated, and so far in studies reported in the literature only the influences of age, diet, phylogeny and digestive tract structures have been considered. This study explicitly challenges the underexplored relationship connecting gut volume and bacterial diversity.
  
  
  RESULTS
  The bacterial diversity of 189 faeces produced by 71 vertebrate species covering a body mass range of 5.6 log. The animals comprised mammals, birds and reptiles. The diversity was evaluated based on the Simpson Diversity Index extracted from 16S rDNA gene fingerprinting patterns. Diversity presented an increase along with animal body mass following a power law with a slope z of 0.338 ± 0.027, whatever the age, phylogeny, diet or digestive tract structure.
  
  
  CONCLUSIONS
  The results presented here suggest that gut volume cannot be neglected as a major driver of gut microbial diversity. The characteristics of the gut microbiota follow general principles of biogeography that arise in many ecological systems.
authors.affiliation: UR0050, Laboratoire de Biotechnologie de l'Environnement, INRA, 102 avenue des étangs, 11100, Narbonne, France. jean-jacques.godon@supagro.inra.fr.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Godon
authors.affiliation: UR0050, Laboratoire de Biotechnologie de l'Environnement, INRA, 102 avenue des étangs, 11100, Narbonne, France.|Centre of Excellence in Environmental Studies, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Pugazhendi
authors.initials: P
authors.lastname: Arulazhagan
authors.affiliation: UR0050, Laboratoire de Biotechnologie de l'Environnement, INRA, 102 avenue des étangs, 11100, Narbonne, France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Steyer
authors.affiliation: UR0050, Laboratoire de Biotechnologie de l'Environnement, INRA, 102 avenue des étangs, 11100, Narbonne, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Hamelin
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D002675:Child, Preschool; D005243:Feces / Q000382:microbiology; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D007223:Infant; D008297:Male; D064307:Microbiota; D009929:Organ Size; D014714:Vertebrates / Q000382:microbiology*; D055815:Young Adult
keywords: Biodiversity; Biogeography; Fingerprint; Gut; Species-area relationship