Stable coexistence of incompatible Wolbachia along a narrow contact zone in mosquito field populations
In arthropods, the intracellular bacteria Wolbachia often induce cytoplasmic incompatibility (CI) between sperm and egg, which causes conditional embryonic death and promotes the spatial spread of Wolbachia infections into host populations. The ability of Wolbachia to spread in natural populations t...
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Published in | Molecular ecology Vol. 24; no. 2; pp. 508 - 521 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Blackwell Publishing Ltd
01.01.2015
Wiley |
Subjects | |
Online Access | Get full text |
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Summary: | In arthropods, the intracellular bacteria Wolbachia often induce cytoplasmic incompatibility (CI) between sperm and egg, which causes conditional embryonic death and promotes the spatial spread of Wolbachia infections into host populations. The ability of Wolbachia to spread in natural populations through CI has attracted attention for using these bacteria in vector‐borne disease control. The dynamics of incompatible Wolbachia infections have been deeply investigated theoretically, whereas in natural populations, there are only few examples described, especially among incompatible infected hosts. Here, we have surveyed the distribution of two molecular Wolbachia strains (wPip11 and wPip31) infecting the mosquito Culex pipiens in Tunisia. We delineated a clear spatial structure of both infections, with a sharp contact zone separating their distribution areas. Crossing experiments with isofemale lines from different localities showed three crossing types: wPip11‐infected males always sterilize wPip31‐infected females; however, while most wPip31‐infected males were compatible with wPip11‐infected females, a few completely sterilize them. The wPip11 strain was thus expected to spread, but temporal dynamics over 7 years of monitoring shows the stability of the contact zone. We examined which factors may contribute to the observed stability, both theoretically and empirically. Population cage experiments, field samples and modelling did not support significant impacts of local adaptation or assortative mating on the stability of wPip infection structure. By contrast, low dispersal probability and metapopulation dynamics in the host Cx. pipiens probably play major roles. This study highlights the need of understanding CI dynamics in natural populations to design effective and sustainable Wolbachia‐based control strategies. |
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Bibliography: | ark:/67375/WNG-GVD7WHJ3-W istex:F7C222DCC9B48D6204EC7D0DBE8C1B149EB735F3 Table S1 Distribution of the molecular Wolbachia strains wPip11 and wPip31 infecting Culex pipiens field samples from Algeria and Tunisia. Table S2 List of primers and characteristics of genes used to examine the Wolbachia and Culex pipiens polymorphisms. Table S3 Reciprocal crosses between wPip11 and wPip31 infected isofemale lines from allopatric localities. Table S4 Reciprocal crosses between sympatric wPip11 and wPip31 infected mosquitoes. Table S5 Crossing relationships of wPip11 males. Table S6 Estimation of the frequencies of wPip31_U and wPip31_B cytotypes among wPip31 infected mosquitoes. Table S7 Occurrence of pipiens and molestus forms of Culex pipiens taxa among wPip11 and wPip31 infected mosquitoes in Tunisia, identified by the CQ11 microsatellite locus. Fig. S1 Patterns of ank2 and MutL PCR markers in wPip11 and wPip31 molecular strains. Fig. S2 Effect of dispersal probability on the progression of the wPip11 cytotype into increasingly distant demes, with or without assortative mating. ArticleID:MEC13035 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0962-1083 1365-294X |
DOI: | 10.1111/mec.13035 |