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Wolbachia-driven selective sweep in a range expanding insect species

Deng, Junchen ; Assandri, Giacomo ; Chauhan, Pallavi LU ; Futahashi, Ryo ; Galimberti, Andrea ; Hansson, Bengt LU orcid ; Lancaster, Lesley T. ; Takahashi, Yuma ; Svensson, Erik I. LU orcid and Duplouy, Anne LU (2021) In BMC Ecology and Evolution 21(1).
Abstract

Background: Evolutionary processes can cause strong spatial genetic signatures, such as local loss of genetic diversity, or conflicting histories from mitochondrial versus nuclear markers. Investigating these genetic patterns is important, as they may reveal obscured processes and players. The maternally inherited bacterium Wolbachia is among the most widespread symbionts in insects. Wolbachia typically spreads within host species by conferring direct fitness benefits, and/or by manipulating its host reproduction to favour infected over uninfected females. Under sufficient selective advantage, the mitochondrial haplotype associated with the favoured maternally-inherited symbiotic strains will spread (i.e. hitchhike), resulting in low... (More)

Background: Evolutionary processes can cause strong spatial genetic signatures, such as local loss of genetic diversity, or conflicting histories from mitochondrial versus nuclear markers. Investigating these genetic patterns is important, as they may reveal obscured processes and players. The maternally inherited bacterium Wolbachia is among the most widespread symbionts in insects. Wolbachia typically spreads within host species by conferring direct fitness benefits, and/or by manipulating its host reproduction to favour infected over uninfected females. Under sufficient selective advantage, the mitochondrial haplotype associated with the favoured maternally-inherited symbiotic strains will spread (i.e. hitchhike), resulting in low mitochondrial genetic variation across the host species range. Method: The common bluetail damselfly (Ischnura elegans: van der Linden, 1820) has recently emerged as a model organism for genetics and genomic signatures of range expansion during climate change. Although there is accumulating data on the consequences of such expansion on the genetics of I. elegans, no study has screened for Wolbachia in the damselfly genus Ischnura. Here, we present the biogeographic variation in Wolbachia prevalence and penetrance across Europe and Japan (including samples from 17 populations), and from close relatives in the Mediterranean area (i.e. I. genei: Rambur, 1842; and I. saharensis: Aguesse, 1958). Results: Our data reveal (a) multiple Wolbachia-strains, (b) potential transfer of the symbiont through hybridization, (c) higher infection rates at higher latitudes, and (d) reduced mitochondrial diversity in the north-west populations, indicative of hitchhiking associated with the selective sweep of the most common strain. We found low mitochondrial haplotype diversity in the Wolbachia-infected north-western European populations (Sweden, Scotland, the Netherlands, Belgium, France and Italy) of I. elegans, and, conversely, higher mitochondrial diversity in populations with low penetrance of Wolbachia (Ukraine, Greece, Montenegro and Cyprus). The timing of the selective sweep associated with infected lineages was estimated between 20,000 and 44,000 years before present, which is consistent with the end of the last glacial period about 20,000 years. Conclusions: Our findings provide an example of how endosymbiont infections can shape spatial variation in their host evolutionary genetics during postglacial expansion. These results also challenge population genetic studies that do not consider the prevalence of symbionts in many insects, which we show can impact geographic patterns of mitochondrial genetic diversity.

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organization
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Contribution to journal
publication status
published
subject
keywords
Damselfly, Endosymbiosis, Genetic diversity, Mitochondria, Phylogeography
in
BMC Ecology and Evolution
volume
21
issue
1
article number
181
publisher
Springer
external identifiers
  • scopus:85115725948
  • pmid:34563127
ISSN
2730-7182
DOI
10.1186/s12862-021-01906-6
language
English
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yes
id
934d1052-b73a-4d8d-87d8-0f61b21ae952
date added to LUP
2021-10-06 21:57:19
date last changed
2024-06-15 17:28:30
@article{934d1052-b73a-4d8d-87d8-0f61b21ae952,
  abstract     = {{<p>Background: Evolutionary processes can cause strong spatial genetic signatures, such as local loss of genetic diversity, or conflicting histories from mitochondrial versus nuclear markers. Investigating these genetic patterns is important, as they may reveal obscured processes and players. The maternally inherited bacterium Wolbachia is among the most widespread symbionts in insects. Wolbachia typically spreads within host species by conferring direct fitness benefits, and/or by manipulating its host reproduction to favour infected over uninfected females. Under sufficient selective advantage, the mitochondrial haplotype associated with the favoured maternally-inherited symbiotic strains will spread (i.e. hitchhike), resulting in low mitochondrial genetic variation across the host species range. Method: The common bluetail damselfly (Ischnura elegans: van der Linden, 1820) has recently emerged as a model organism for genetics and genomic signatures of range expansion during climate change. Although there is accumulating data on the consequences of such expansion on the genetics of I. elegans, no study has screened for Wolbachia in the damselfly genus Ischnura. Here, we present the biogeographic variation in Wolbachia prevalence and penetrance across Europe and Japan (including samples from 17 populations), and from close relatives in the Mediterranean area (i.e. I. genei: Rambur, 1842; and I. saharensis: Aguesse, 1958). Results: Our data reveal (a) multiple Wolbachia-strains, (b) potential transfer of the symbiont through hybridization, (c) higher infection rates at higher latitudes, and (d) reduced mitochondrial diversity in the north-west populations, indicative of hitchhiking associated with the selective sweep of the most common strain. We found low mitochondrial haplotype diversity in the Wolbachia-infected north-western European populations (Sweden, Scotland, the Netherlands, Belgium, France and Italy) of I. elegans, and, conversely, higher mitochondrial diversity in populations with low penetrance of Wolbachia (Ukraine, Greece, Montenegro and Cyprus). The timing of the selective sweep associated with infected lineages was estimated between 20,000 and 44,000 years before present, which is consistent with the end of the last glacial period about 20,000 years. Conclusions: Our findings provide an example of how endosymbiont infections can shape spatial variation in their host evolutionary genetics during postglacial expansion. These results also challenge population genetic studies that do not consider the prevalence of symbionts in many insects, which we show can impact geographic patterns of mitochondrial genetic diversity.</p>}},
  author       = {{Deng, Junchen and Assandri, Giacomo and Chauhan, Pallavi and Futahashi, Ryo and Galimberti, Andrea and Hansson, Bengt and Lancaster, Lesley T. and Takahashi, Yuma and Svensson, Erik I. and Duplouy, Anne}},
  issn         = {{2730-7182}},
  keywords     = {{Damselfly; Endosymbiosis; Genetic diversity; Mitochondria; Phylogeography}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{Springer}},
  series       = {{BMC Ecology and Evolution}},
  title        = {{Wolbachia-driven selective sweep in a range expanding insect species}},
  url          = {{http://dx.doi.org/10.1186/s12862-021-01906-6}},
  doi          = {{10.1186/s12862-021-01906-6}},
  volume       = {{21}},
  year         = {{2021}},
}