| 1. |
- Arnqvist, Göran, Professor, 1961-, et al.
(författare)
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The pace-of-life : A sex-specific link between metabolic rate and life history in bean beetles
- 2017
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 31:12, s. 2299-2309
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Tidskriftsartikel (refereegranskat)abstract
- Metabolic rate (MR) is a key functional trait simply because metabolism converts resources into population growth rate. Yet, our empirical understanding of the sources of within species variation in MR, as well as of its life history and ecological correlates, is rather limited. Here, we assess whether MR lies at the root of a syndrome of correlated rate-dependent life-history traits in an insect.Selection for early (E) or late (L) age-at-reproduction for >160 generations in the bean beetle Acanthoscelides obtectus has produced beetles that differ markedly in juvenile development, body size, fecundity schedules, ageing and life span. Here, we use micro-respirometry to test whether this has been associated with the evolution of age- and sex-specific metabolic phenotypes.We find that mass-specific MR is 18% higher in E lines compared to L lines and that MR decreases more rapidly with chronological, but not biological, age in E lines. Males, under sexual selection to “live-fast-die-young”, show 50% higher MR than females and MR decreased more rapidly with age in males.Our results are consistent with a central role for MR for the divergence in “pace-of-life” seen in these beetles, supporting the view that MR lies at the root of ecologically relevant life-history trait variation within species.
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| 2. |
- Dordevic, Mirko, et al.
(författare)
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Sex-specific mitonuclear epistasis and the evolution of mitochondrial bioenergetics, ageing, and life history in seed beetles
- 2017
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Ingår i: Evolution. - : WILEY. - 0014-3820 .- 1558-5646. ; 71:2, s. 274-288
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Tidskriftsartikel (refereegranskat)abstract
- The role of mitochondrial DNA for the evolution of life-history traits remains debated. We examined mitonuclear effects on the activity of the multisubunit complex of the electron transport chain (ETC) involved in oxidative phosphorylation (OXPHOS) across lines of the seed beetle Acanthoscelides obtectus selected for a short (E) or a long (L) life for more than >160 generations. We constructed and phenotyped mitonuclear introgression lines, which allowed us to assess the independent effects of the evolutionary history of the nuclear and the mitochondrial genome. The nuclear genome was responsible for the largest share of divergence seen in ageing. However, the mitochondrial genome also had sizeable effects, which were sex-specific and expressed primarily as epistatic interactions with the nuclear genome. The effects of mitonuclear disruption were largely consistent with mitonuclear coadaptation. Variation in ETC activity explained a large proportion of variance in ageing and life-history traits and this multivariate relationship differed somewhat between the sexes. In conclusion, mitonuclear epistasis has played an important role in the laboratory evolution of ETC complex activity, ageing, and life histories and these are closely associated. The mitonuclear architecture of evolved differences in life-history traits and mitochondrial bioenergetics was sex-specific.
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| 3. |
- Stojkovic, Biljana, et al.
(författare)
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Divergent evolution of life span associated with mitochondrial DNA evolution
- 2017
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Ingår i: Evolution. - : WILEY-BLACKWELL. - 0014-3820 .- 1558-5646. ; 71:1, s. 160-166
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Tidskriftsartikel (refereegranskat)abstract
- Mitochondria play a key role in ageing. The pursuit of genes that regulate variation in life span and ageing have shown that several nuclear-encoded mitochondrial genes are important. However, the role of mitochondrial encoded genes (mtDNA) is more controversial and our appreciation of the role of mtDNA for the evolution of life span is limited. We use replicated lines of seed beetles that have been artificially selected for long or short life for >190 generations, now showing dramatic phenotypic differences, to test for a possible role of mtDNA in the divergent evolution of ageing and life span. We show that these divergent selection regimes led to the evolution of significantly different mtDNA haplotype frequencies. Selection for a long life and late reproduction generated positive selection for one specific haplotype, which was fixed in most such lines. In contrast, selection for reproduction early in life led to both positive selection as well as negative frequency-dependent selection on two different haplotypes, which were both present in all such lines. Our findings suggest that the evolution of life span was in part mediated by mtDNA, providing support for the emerging general tenet that adaptive evolution of life-history syndromes may involve mtDNA.
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