title: The diversity of reproductive parasites among arthropods: Wolbachia do not walk alone.
abstract: BACKGROUND
  Inherited bacteria have come to be recognised as important components of arthropod biology. In addition to mutualistic symbioses, a range of other inherited bacteria are known to act either as reproductive parasites or as secondary symbionts. Whilst the incidence of the alpha-proteobacterium Wolbachia is relatively well established, the current knowledge of other inherited bacteria is much weaker. Here, we tested 136 arthropod species for a range of inherited bacteria known to demonstrate reproductive parasitism, sampling each species more intensively than in past surveys.
  
  
  RESULTS
  The inclusion of inherited bacteria other than Wolbachia increased the number of infections recorded in our sample from 33 to 57, and the proportion of species infected from 22.8% to 32.4%. Thus, whilst Wolbachia remained the dominant inherited bacterium, it alone was responsible for around half of all inherited infections of the bacteria sampled, with members of the Cardinium, Arsenophonus and Spiroplasma ixodetis clades each occurring in 4% to 7% of all species. The observation that infection was sometimes rare within host populations, and that there was variation in presence of symbionts between populations indicates that our survey will itself underscore incidence.
  
  
  CONCLUSIONS
  This extensive survey demonstrates that at least a third of arthropod species are infected by a diverse assemblage of maternally inherited bacteria that are likely to strongly influence their hosts' biology, and indicates an urgent need to establish the nature of the interaction between non-Wolbachia bacteria and their hosts.
authors.affiliation: University College London, Department of Biology, Stephenson Way, London NW1 2HE, UK. o.duron@ucl.ac.uk
authors.forename: Olivier
authors.initials: O
authors.lastname: Duron
authors.forename: Didier
authors.initials: D
authors.lastname: Bouchon
authors.forename: Sébastien
authors.initials: S
authors.lastname: Boutin
authors.forename: Lawrence
authors.initials: L
authors.lastname: Bellamy
authors.forename: Liqin
authors.initials: L
authors.lastname: Zhou
authors.forename: Jan
authors.initials: J
authors.lastname: Engelstädter
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Hurst
mesh_terms: D000818:Animals; D001181:Arthropods / Q000382:microbiology*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D018407:Bacterial Physiological Phenomena; D044822:Biodiversity; D005260:Female; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D020577:Wolbachia / Q000254:growth & development* / Q000502:physiology*