Bacterial Community Diversity Harboured by Interacting Species.
All animals are infected by microbial partners that can be passengers or residents and influence many biological traits of their hosts. Even if important factors that structure the composition and abundance of microbial communities within and among host individuals have been recently described, such as diet, developmental stage or phylogeny, few studies have conducted cross-taxonomic comparisons, especially on host species related by trophic relationships. Here, we describe and compare the microbial communities associated with the cabbage root fly Delia radicum and its three major parasitoids: the two staphylinid beetles Aleochara bilineata and A. bipustulata and the hymenopteran parasitoid Trybliographa rapae. For each species, two populations from Western France were sampled and microbial communities were described through culture independent methods (454 pyrosequencing). Each sample harbored at least 59 to 261 different bacterial phylotypes but was strongly dominated by one or two. Microbial communities differed markedly in terms of composition and abundance, being mainly influenced by phylogenetic proximity but also geography to a minor extent. Surprisingly, despite their strong trophic interaction, parasitoids shared a very low proportion of microbial partners with their insect host. Three vertically transmitted symbionts from the genus Wolbachia, Rickettsia, and Spiroplasma were found in this study. Among them, Wolbachia and Spiroplasma were found in both the cabbage fly and at least one of its parasitoids, which could result from horizontal transfers through trophic interactions. Phylogenetic analysis showed that this hypothesis may explain some but not all cases. More work is needed to understand the dynamics of symbiotic associations within trophic network and the effect of these bacterial communities on the fitness of their hosts.
Université Rennes 1, UMR1349 IGEPP, F-35000, Rennes, France.|Université Européenne de Bretagne, Rennes, France.
Mikaël
M
Bili
Université Rennes 1, UMR1349 IGEPP, F-35000, Rennes, France.|Université Européenne de Bretagne, Rennes, France.
Anne Marie
AM
Cortesero
INRA, UMR1349 IGEPP, F-35000, Rennes, France.
Christophe
C
Mougel
INRA, UMR1349 IGEPP, F-35000, Rennes, France.
Jean Pierre
JP
Gauthier
UMR CNRS 6026 Interactions Cellulaires et Moléculaires, Université de Rennes, Rennes, France.
Gwennola
G
Ermel
INRA, UMR1349 IGEPP, F-35000, Rennes, France.
Jean Christophe
JC
Simon
Agrocampus Ouest, UMR1349 IGEPP, F-35000, Rennes, France.
Yannick
Y
Outreman
UMR 1347 Agroécologie, Université de Bourgogne, Dijon, France.
Sébastien
S
Terrat
INRA, UMR1349 IGEPP, F-35000, Rennes, France.
Frédérique
F
Mahéo
Université Rennes 1, UMR1349 IGEPP, F-35000, Rennes, France.|Université Européenne de Bretagne, Rennes, France.
Denis
D
Poinsot
D000818:Animals; D044822:Biodiversity; D001517:Coleoptera / Q000382:microbiology*; D004175:Diptera / Q000382:microbiology* / Q000469:parasitology; D064307:Microbiota