| 51. |
- Silva, Willian T.A.F.
(författare)
-
Digest : A synergistic approach explains the evolutionary connection between brain size and longevity*
- 2020
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 74:12, s. 2743-2745
-
Tidskriftsartikel (refereegranskat)abstract
- The cognitive buffer hypothesis poses that brain size evolves to buffer individuals from environmental changes, increasing survival. Jiménez-Ortega et al. (2020) explored this hypothesis using a phylogenetic path analysis and showed that there is a direct causal link between brain size and longevity in birds, even when allometric effects are taken into account. Furthermore, a synergistic model was better supported than models that included independent effects of brain size and body size.
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| 52. |
- Sowersby, Will, et al.
(författare)
-
Fast life-histories are associated with larger brain size in killifishes
- 2021
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 75:9, s. 2286-2298
-
Tidskriftsartikel (refereegranskat)abstract
- The high energetic demands associated with the vertebrate brain are proposed to result in a trade-off between the pace of life-history and relative brain size. However, because both life-history and brain size also have a strong relationship with body size, any associations between the pace of life-history and relative brain size may be confounded by coevolution with body size. Studies on systems where contrasts in the pace of life-history occur without concordant contrasts in body size could therefore add to our understanding of the potential coevolution between relative brain size and life-history. Using one such system - 21 species of killifish - we employed a common garden design across two ontogenetic stages to investigate the association between relative brain size and the pace of life-history. Contrary to predictions, we found that relative brain size was larger in adult fast-living killifishes, compared to slow-living species. Although we found no differences in relative brain size between juvenile killifishes. Our results suggest that fast- and slow-living killifishes do not exhibit the predicted trade-off between brain size and life-history. Instead, fast and slow-living killifishes could differ in the ontogenetic timing of somatic versus neural growth or inhabit environments that differ considerably in cognitive demands.
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| 53. |
- Sowersby, Will, et al.
(författare)
-
The relative effects of pace of life-history and habitat characteristics on the evolution of sexual ornaments : A comparative assessment
- 2022
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 76:1, s. 114-127
-
Tidskriftsartikel (refereegranskat)abstract
- Selection may favor greater investment into sexual ornaments when opportunities for future reproduction are limited, for example, under high adult mortality. However, predation, a key driver of mortality, typically selects against elaborate sexual ornaments. Here, we examine the evolution of sexual ornaments in killifishes, which have marked contrasts in life-history strategy among species and inhabit environments that differ in accessibility to aquatic predators. We first assessed if the size of sexual ornaments (unpaired fins) influenced swimming performance. Second, we investigated whether the evolution of larger ornamental fins is driven primarily by the pace of life-history (investment into current vs. future reproduction) or habitat type (a proxy for predation risk). We found that larger fins negatively affected swimming performance. Further, males from species inhabiting ephemeral habitats, with lower predation risk, had larger fins and greater sexual dimorphism in fin size, compared to males from more accessible permanent habitats. We show that enlarged ornamental fins, which impair locomotion, evolve more frequently in environments that are less accessible to predators, without clear associations to life-history strategy. Our results provide a rare link between the evolution of sexual ornaments, effects on locomotion performance, and natural selection on ornament size potentially through habitat differences in predation risk.
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| 54. |
- Steward, Rachel A., et al.
(författare)
-
Novel host unmasks heritable variation in plant preference within an insect population
- 2022
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 76:11, s. 2634-2648
-
Tidskriftsartikel (refereegranskat)abstract
- Introductions of novel plant species can disturb the historical resource environment of herbivorous insects, resulting in strong selection to either adopt or exclude the novel host. However, an adaptive response depends on heritable genetic variation for preference or performance within the targeted herbivore population, and it is unclear how heritability of host-use preference may differ between novel and historical hosts. Pieris macdunnoughii butterflies in the Rocky Mountains lay eggs on the nonnative mustard Thlaspi arvense, which is lethal to their offspring. Heritability analyses revealed considerable sex-linked additive genetic variation in host preference within a population of this butterfly. This was contrary to general predictions about the genetic basis of preference variation, which are hypothesized to be sex linked between populations but autosomal within populations. Evidence of sex linkage disappeared when butterflies were tested on methanol-based chemical extracts, suggesting these chemicals in isolation may not be the primary driver of female choice among available host plants. Although unexpected, evidence for within-population sex-linked genetic variation in preference for T. arvense over native hosts indicates that persistent maladaptive oviposition on this lethal plant must be maintained by alternative evolutionary dynamics such as migration- or drift-selection balance or pleiotropic constraints.
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| 55. |
- Stoy, Kayla S., et al.
(författare)
-
Evaluating coevolution in a horizontally transmitted mutualism
- 2023
-
Ingår i: Evolution. - : OXFORD UNIV PRESS. - 0014-3820 .- 1558-5646. ; 77:1, s. 166-185
-
Tidskriftsartikel (refereegranskat)abstract
- Many interspecific interactions are shaped by coevolution. Transmission mode is thought to influence opportunities for coevolution within symbiotic interactions. Vertical transmission maintains partner fidelity, increasing opportunities for coevolution, but horizontal transmission may disrupt partner fidelity, potentially reducing opportunities for coevolution. Despite these predictions, the role of coevolution in the maintenance of horizontally transmitted symbioses is unclear. Leveraging a tractable insect-bacteria symbiosis, we tested for signatures of pairwise coevolution by assessing patterns of host-symbiont specialization. If pairwise coevolution defines the interaction, we expected to observe evidence of reciprocal specialization between hosts and their local symbionts. We found no evidence for local adaptation between sympatric lineages of Anasa tristis squash bugs and Caballeronia spp. symbionts across their native geographic range. We also found no evidence for specialization between three co-localized Anasa host species and their native Caballeronia symbionts. Our results demonstrate generalist dynamics underlie the interaction between Anasa insect hosts and their Caballeronia symbionts. We predict that selection from multiple host species may favor generalist symbiont traits through diffuse coevolution. Alternatively, selection for generalist traits may be a consequence of selection by hosts for fixed cooperative symbiont traits without coevolution.
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| 56. |
- Strickland, Kasha, et al.
(författare)
-
Repeatability and heritability of social reaction norms in a wild agamid lizard
- 2021
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 75:8, s. 1953-1965
-
Tidskriftsartikel (refereegranskat)abstract
- In the evolutionary transition from solitary to group living, it should be adaptive for animals to respond to the environment and choose when to socialize to reduce conflict and maximize access to resources. Due to the associated proximate mechanisms (e.g. neural network, endocrine system), it is likely that this behavior varies between individuals according to genetic and non-genetic factors. We used long-term behavioral and genetic data from a population of eastern water dragons (Intellagama lesueurii) to explore variation in plasticity of social behavior, in response to sex ratio and density. To do so, we modeled individual variation in social reaction norms, which describe individuals’ mean behavior and behavioral responses to changes in their environment, and partitioned variance into genetic and non-genetic components. We found that reaction norms were repeatable over multiple years, suggesting that individuals consistently differed in their behavioral responses to changes in the social environment. Despite high repeatability of reaction norm components, trait heritability was below our limit of detection based on power analyses (h2 < 0.12), leading to very little power to detect heritability of plasticity. This was in contrast to a relatively greater amount of variance associated with environmental effects. This could suggest that mechanisms such as social learning and frequency-dependence may shape variance in reaction norms, which will be testable as the dataset grows.
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| 57. |
- Tolvanen, Jere, et al.
(författare)
-
Quantitative genetics of the use of conspecific and heterospecific social cues for breeding site choice
- 2020
-
Ingår i: Evolution. - : WILEY. - 0014-3820 .- 1558-5646. ; 74:10, s. 2332-2347
-
Tidskriftsartikel (refereegranskat)abstract
- Social information use for decision-making is common and affects ecological and evolutionary processes, including social aggregation, species coexistence, and cultural evolution. Despite increasing ecological knowledge on social information use, very little is known about its genetic basis and therefore its evolutionary potential. Genetic variation in a trait affecting an individual's social and nonsocial environment may have important implications for population dynamics, interspecific interactions, and, for expression of other, environmentally plastic traits. We estimated repeatability, additive genetic variance, and heritability of the use of conspecific and heterospecific social cues (abundance and breeding success) for breeding site choice in a population of wild collared flycatchersFicedula albicollis. Repeatability was found for two social cues: previous year conspecific breeding success and previous year heterospecific abundance. Yet, additive genetic variances for these two social cues, and thus heritabilities, were low. This suggests that most of the phenotypic variation in the use of social cues and resulting conspecific and heterospecific social environment experienced by individuals in this population stems from phenotypic plasticity. Given the important role of social information use on ecological and evolutionary processes, more studies on genetic versus environmental determinism of social information use are needed.
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| 58. |
- Triki, Zegni, et al.
(författare)
-
Artificial mosaic brain evolution of relative telencephalon size improves inhibitory control abilities in the guppy (Poecilia reticulata)
- 2022
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 76:1, s. 128-138
-
Tidskriftsartikel (refereegranskat)abstract
- Mosaic brain evolution, the change in the size of separate brain regions in response to selection on cognitive performance, is an important idea in the field of cognitive evolution. However, untill now, most of the data on how separate brain regions respond to selection and their cognitive consequences stem from comparative studies. To experimentally investigate the influence of mosaic brain evolution on cognitive ability, we used male guppies artificially selected for large and small telencephalons relative to the rest of the brain. Here, we tested an important aspect of executive cognitive ability using a detour task. We found that males with larger telencephalons outperformed males with smaller telencephalons. Fish with larger telencephalons showed faster improvement in performance during detour training and were more successful in reaching the food reward without touching the transparent barrier (i.e., through correct detouring) during the test phase. Together, our findings provide the first experimental evidence showing that evolutionary enlargement of relative telencephalon size confers cognitive benefits, supporting an important role for mosaic brain evolution during cognitive evolution.
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| 59. |
- Trunschke, Judith, et al.
(författare)
-
Manipulation of trait expression and pollination regime reveals the adaptive significance of spur length
- 2020
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 74:3, s. 597-609
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the mechanisms of adaptive population differentiation requires that both the functional and adaptive significance of divergent traits are characterized in contrasting environments. Here, we (a) determined the effects of floral spur length on pollen removal and receipt using plants with artificial spurs representing the species‐wide variation in length, and (b) quantified pollinator‐mediated selection on spur length and three traits contributing to floral display in two populations each of the short‐spurred and the long‐spurred ecotype of the orchid Platanthera bifolia. Both pollen receipt and removal reached a maximum at 28–29 mm long spurs in a short‐spurred population visited by short‐tongued moths. In contrast, pollen receipt increased linearly across the tested range (4–52 mm) and pollen removal was unrelated to spur length in a long‐spurred population predominantly visited by a long‐tongued moth. The experimentally documented effects on pollen transfer were not reflected in pollinator‐mediated selection through female fitness or pollen removal indicating that the natural within‐population variation in spur length was insufficient to result in detectable variation in pollen limitation. Our study illustrates how combining trait manipulation with analysis of causes and strength of phenotypic selection can illuminate the functional and adaptive significance of trait expression when trait variation is limited.
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| 60. |
- Vallejo‐Marín, Mario, et al.
(författare)
-
Anther cones increase pollen release in buzz‐pollinated Solanum flowers
- 2022
-
Ingår i: Evolution. - : John Wiley & Sons. - 0014-3820 .- 1558-5646. ; 76:5, s. 931-945
-
Tidskriftsartikel (refereegranskat)abstract
- The widespread evolution of tube-like anthers releasing pollen from apical pores is associated with buzz pollination, in which bees vibrate flowers to remove pollen. The mechanical connection among anthers in buzz-pollinated species varies from loosely held conformations, to anthers tightly held together with trichomes or bioadhesives forming a functionally joined conical structure (anther cone). Joined anther cones in buzz-pollinated species have evolved independently across plant families and via differ- ent genetic mechanisms, yet their functional significance remains mostly untested. We used experimental manipulations to com- pare vibrational and functional (pollen release) consequences of joined anther cones in three buzz-pollinated species of Solanum (Solanaceae). We applied bee-like vibrations to focal anthers in flowers with (“joined”) and without (“free”) experimentally created joined anther cones, and characterized vibrations transmitted to other anthers and the amount of pollen released. We found that joined anther architectures cause nonfocal anthers to vibrate at higher amplitudes than free architectures. Moreover, in the two species with naturally loosely held anthers, anther fusion increases pollen release, whereas in the species with a free but naturally compact architecture it does not. We discuss hypotheses for the adaptive significance of the convergent evolution of joined anther cones.
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| 61. |
- Vinterstare, Jerker, et al.
(författare)
-
Sex matters : predator presence induces sexual dimorphism in a monomorphic prey, from stress genes to morphological defences
- 2023
-
Ingår i: Evolution; international journal of organic evolution. - : Oxford University Press (OUP). - 1558-5646. ; 77:1, s. 304-317
-
Tidskriftsartikel (refereegranskat)abstract
- Inducible defences allow prey to increase survival chances when predators are present while avoiding unnecessary costs in their absence. Many studies report considerable inter-individual variation in inducible defence expression, yet what underlies this variation is poorly understood. A classic vertebrate example of a predator-induced morphological defence is the increased body depth in crucian carp (Carassius carassius), which reduces the risk of predation from gape-size limited predators. Here, we report that among-individual variation in morphological defence expression can be linked to sex. We documented sexual dimorphism in lakes in which crucian carp coexisted with predators, where females showed shallower relative body depths than males, but not in a predator-free lake. When exposing crucian carp from a population without predators to perceived predation risk in a laboratory environment (presence/absence of pike, Esox lucius), we found that males expressed significantly greater morphological defence than females, causing sexual dimorphism only in the presence of predators. We uncovered a correlative link between the sex-specific inducible phenotypic response and gene expression patterns in major stress-related genes (POMC, MC3R, and MC4R). Together, our results highlight that sex-specific responses may be an important, yet underappreciated, component underlying inter-individual differences in the expression of inducible defences, even in species without pronounced sexual dimorphism.
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| 62. |
- Vogan, Aaron A., et al.
(författare)
-
Meiotic drive is associated with sexual incompatibility in Neurospora
- 2022
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 76:11, s. 2687-2696
-
Tidskriftsartikel (refereegranskat)abstract
- Evolution of Bateson-Dobzhansky-Muller (BDM) incompatibilities is thought to represent a key step in the formation of separate species. They are incompatible alleles that have evolved in separate populations and are exposed in hybrid offspring as hybrid sterility or lethality. In this study, we reveal a previously unconsidered mechanism promoting the formation of BDM incompatibilities, meiotic drive. Theoretical studies have evaluated the role that meiotic drive, the phenomenon whereby selfish elements bias their transmission to progeny at ratios above 50:50, plays in speciation, and have mostly concluded that drive could not result in speciation on its own. Using the model fungus Neurospora, we demonstrate that the large meiotic drive haplotypes, Sk-2 and Sk-3, contain putative sexual incompatibilities. Our experiments revealed that although crosses between Neurospora intermedia and Neurospora metzenbergii produce viable progeny at appreciable rates, when strains of N. intermedia carry Sk-2 or Sk-3 the proportion of viable progeny drops substantially. Additionally, it appears that Sk-2 and Sk-3 have accumulated different incompatibility phenotypes, consistent with their independent evolutionary history. This research illustrates how meiotic drive can contribute to reproductive isolation between populations, and thereby speciation.
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| 63. |
- Weng, Mao-Lun, et al.
(författare)
-
Fitness effects of mutation in natural populations of Arabidopsis thaliana reveal a complex influence of local adaptation
- 2021
-
Ingår i: Evolution. - : John Wiley & Sons. - 0014-3820 .- 1558-5646. ; 75:2, s. 330-348
-
Tidskriftsartikel (refereegranskat)abstract
- Little is empirically known about the contribution of mutations to fitness in natural environments. However, Fisher's Geometric Model (FGM) provides a conceptual foundation to consider the influence of the environment on mutational effects. To quantify mutational properties in the field, we established eight sets of MA lines (7-10 generations) derived from eight founders collected from natural populations of Arabidopsis thaliana from French and Swedish sites, representing the range margins of the species in Europe. We reciprocally planted the MA lines and their founders at French and Swedish sites, allowing us to test predictions of FGM under naturally occurring environmental conditions. The performance of the MA lines relative to each other and to their respective founders confirmed some and contradicted other predictions of the FGM: the contribution of mutation to fitness variance increased when the genotype was in an environment where its fitness was low, that is, in the away environment, but mutations were more likely to be beneficial when the genotype was in its home environment. Consequently, environmental context plays a large role in the contribution of mutations to the evolutionary process and local adaptation does not guarantee that a genotype is at or close to its optimum.
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| 64. |
- White, N. J., et al.
(författare)
-
Multidimensional divergent selection, local adaptation, and speciation
- 2021
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 75:9, s. 2167-2178
-
Tidskriftsartikel (refereegranskat)abstract
- Divergent selection applied to one or more traits drives local adaptation and may lead to ecological speciation. Divergent selection on many traits might be termed "multidimensional" divergent selection. There is a commonly held view that multidimensional divergent selection is likely to promote local adaptation and speciation to a greater extent than unidimensional divergent selection. We disentangle the core concepts underlying dimensionality as a property of the environment, phenotypes, and genome. In particular, we identify a need to separate the overall strength of selection and the number of loci affected from dimensionality per se, and to distinguish divergence dimensionality from dimensionality of stabilizing selection. We then critically scrutinize this commonly held view that multidimensional selection promotes speciation, re-examining the evidence base from theory, experiments, and nature. We conclude that the evidence base is currently weak and generally suffers from confounding of possible causal effects. Finally, we propose several mechanisms by which multidimensional divergent selection and related processes might influence divergence, both as a driver and as a barrier.
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| 65. |
- Wiberg, R. Axel W., et al.
(författare)
-
Mating strategy predicts gene presence/absence patterns in a genus of simultaneously hermaphroditic flatworms
- 2022
-
Ingår i: Evolution. - : John Wiley & Sons. - 0014-3820 .- 1558-5646. ; 76:12, s. 3054-3066
-
Tidskriftsartikel (refereegranskat)abstract
- Gene repertoire turnover is a characteristic of genome evolution. However, we lack well-replicated analyses of presence/absence patterns associated with different selection contexts. Here, we study similar to 100 transcriptome assemblies across Macrostomum, a genus of simultaneously hermaphroditic flatworms exhibiting multiple convergent shifts in mating strategy and associated reproductive morphologies. Many species mate reciprocally, with partners donating and receiving sperm at the same time. Other species convergently evolved to mate by hypodermic injection of sperm into the partner. We find that for orthologous transcripts annotated as expressed in the body region containing the testes, sequences from hypodermically inseminating species diverge more rapidly from the model species, Macrostomum lignano, and have a lower probability of being observed in other species. For other annotation categories, simpler models with a constant rate of similarity decay with increasing genetic distance from M. lignano match the observed patterns well. Thus, faster rates of sequence evolution for hypodermically inseminating species in testis-region genes result in higher rates of homology detection failure, yielding a signal of rapid evolution in sequence presence/absence patterns. Our results highlight the utility of considering appropriate null models for unobserved genes, as well as associating patterns of gene presence/absence with replicated evolutionary events in a phylogenetic context.
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| 66. |
- Willink, Beatriz, et al.
(författare)
-
Changes in gene expression during female reproductive development in a color polymorphic insect
- 2020
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 74:6, s. 1063-1081
-
Tidskriftsartikel (refereegranskat)abstract
- Pleiotropy (multiple phenotypic effects of single genes) and epistasis (gene interaction) have key roles in the development of complex phenotypes, especially in polymorphic taxa. The development of discrete and heritable phenotypic polymorphisms often emerges from major-effect genes that interact with other loci and have pleiotropic effects on multiple traits. We quantified gene expression changes during ontogenetic color development in a polymorphic insect (damselfly: Ischnura elegans), with three heritable female morphs, one being a male mimic. This female color polymorphism is maintained by male mating harassment and sexual conflict. Using transcriptome sequencing and de novo assembly, we demonstrate that all three morphs downregulate gene expression during early color development. The morphs become increasingly differentiated during sexual maturation and when developing adult coloration. These different ontogenetic trajectories arise because the male-mimic shows accelerated (heterochronic) development, compared to the other female morphs. Many loci with regulatory functions in reproductive development are differentially regulated in the male-mimic, including upstream and downstream regulators of ecdysone signaling and transcription factors potentially influencing sexual differentiation. Our results suggest that long-term sexual conflict does not only maintain this polymorphism, but has also modulated the evolution of gene expression profiles during color development of these sympatric female morphs.
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| 67. |
|
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| 68. |
- Yang, Weizhao, et al.
(författare)
-
Spatial variation in gene flow across a hybrid zone reveals causes of reproductive isolation and asymmetric introgression in wall lizards
- 2020
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 74:7, s. 1289-1300
-
Tidskriftsartikel (refereegranskat)abstract
- Hybrid zones provide insights into the evolution of reproductive isolation. Sexual selection can contribute to the evolution of reproductive barriers, but it remains poorly understood how sexual traits impact gene flow in secondary contact. Here, we show that a recently evolved suite of sexual traits that function in male-male competition mediates gene flow between two lineages of wall lizards (Podarcis muralis). Gene flow was relatively low and asymmetric in the presence of exaggerated male morphology and coloration compared to when the lineages share the ancestral phenotype. Putative barrier loci were enriched in genomic regions that were highly differentiated between the two lineages and showed low concordance between the transects. The exception was a consistently low genetic exchange around ATXN1, a gene that modulates social behavior. We suggest that this gene may contribute to the male mate preferences that are known to cause lineage-assortative mating in this species. Although female choice modulates the degree of reproductive isolation in a variety of taxa, wall lizards demonstrate that both male-male competition and male mate choice can contribute to the extent of gene flow between lineages.
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| 69. |
- Yazdi, Homa Papoli
(författare)
-
Digest : Neo-sex chromosome underlying the Faster-Z effect in a species of Lepidoptera*
- 2022
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 76:2, s. 357-358
-
Tidskriftsartikel (refereegranskat)abstract
- Do Z chromosomes evolve at a faster rate than autosomes in Lepidoptera? Mongue et al. show that Z-linked genes in two Lepidopteran species evolve faster than autosomal genes. However, the neo-sex chromosome differs from the ancestral chromosome and shows adaptive evolution for genes with a biased expression in the heterogametic sex. These findings indicate that studying molecular evolutionary patterns in sex-linked sequences at different evolutionary stages is essential to understand the dynamics of sex chromosome evolution.
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| 70. |
- Åkesson, Susanne, et al.
(författare)
-
Evolution of chain migration in an aerial insectivorous bird, the common swift Apus apus
- 2020
-
Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 74:10, s. 2377-2391
-
Tidskriftsartikel (refereegranskat)abstract
- Spectacular long-distance migration has evolved repeatedly in animals enabling exploration of resources separated in time and space. In birds, these patterns are largely driven by seasonality, cost of migration, and asymmetries in competition leading most often to leapfrog migration, where northern breeding populations winter furthest to the south. Here, we show that the highly aerial common swift Apus apus, spending the nonbreeding period on the wing, instead exhibits a rarely found chain migration pattern, where the most southern breeding populations in Europe migrate to wintering areas furthest to the south in Africa, whereas the northern populations winter to the north. The swifts concentrated in three major areas in sub-Saharan Africa during the nonbreeding period, with substantial overlap of nearby breeding populations. We found that the southern breeding swifts were larger, raised more young, and arrived to the wintering areas with higher seasonal variation in greenness (Normalized Difference Vegetation Index) earlier than the northern breeding swifts. This unusual chain migration pattern in common swifts is largely driven by differential annual timing and we suggest it evolves by prior occupancy and dominance by size in the breeding quarters and by prior occupancy combined with diffuse competition in the winter.
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| 71. |
- Ålund, Murielle, et al.
(författare)
-
Tracking hybrid viability across life stages in a natural avian contact zone
- 2024
-
Ingår i: Evolution. - : Oxford University Press. - 0014-3820 .- 1558-5646. ; 78:2, s. 267-283
-
Tidskriftsartikel (refereegranskat)abstract
- Hybrid inviability is an important post-zygotic reproductive barrier between species, but emerging signs of reduced viability can be difficult to study across the lifespan of natural hybrids. We use a combination of long-term monitoring, extra-pair paternity, and mitochondrial DNA identification in a natural hybrid zone of Ficedula flycatchers to detect emerging signs of intrinsic hybrid inviability across their entire lifespan. We evaluate possible evidence of Darwin's corollary to Haldane's rule, predicting asymmetries in inviability between hybrids resulting from reciprocal crosses, due to incompatible genetic factors with sex-specific inheritance patterns. We found higher hatching failure among mixed-species pairs, possibly indicating early developmental impairments associated with specific parental genetic combinations. Adult hybrids had a higher basal mortality rate than both parental species and different age-specific mortality trajectories. There were signs of differences in age-independent mortality rates between the reciprocal hybrid crosses: hybrids with a pied flycatcher mother experienced slightly increased mortality later in life. Using an exceptional dataset with many natural hybrids tracked across life stages, we provide evidence for several emerging signs of reduced hybrid viability. Incompatibilities between alleles located on autosomes and uniparentally inherited factors such as Z-linked and/or mitochondrial genes are strong candidates underlying intrinsic hybrid dysfunction in this system.
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| 72. |
- Goldenberg, Jonathan, et al.
(författare)
-
Body size and substrate use affect ventral, but not dorsal, brightness evolution in lizards
- 2023
-
Ingår i: Evolution; international journal of organic evolution. - 1558-5646. ; 77:6, s. 1341-1353
-
Tidskriftsartikel (refereegranskat)abstract
- Substrate properties can affect the thermal balance of organisms, and the colored integument, alongside other factors, may influence heat transfer via differential absorption and reflection. Dark coloration may lead to higher heat absorption and could be advantageous when substrates are cool (and vice versa for bright coloration), but these effects are rarely investigated. Here, we examined the effect of substrate reflectance, specific heat capacity (cp), and body size on the dorso-ventral brightness using 276 samples from 12 species of cordylid lizards distributed across 26 sites in South Africa. We predicted, and found, that bright ventral colors occur more frequently in low cp (i.e., drier, with little energy needed for temperature change) substrates, especially in larger body-sized individuals, possibly to better modulate heat transfer with the surrounding environment. By contrast, dorsal brightness was not associated with body size nor any substrate thermal property, suggesting selection pressures other than thermoregulation. Ancestral estimation and evolutionary rate analyses suggest that ventral brightness rapidly differentiated within the Cordylinae starting 25 Mya, coinciding with an aridification period, further hinting at a thermoregulatory role for ventral colors. Our study indicates that substrate properties can have a direct role in shaping the evolution of ventral brightness in ectotherms.
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| 73. |
- Iglesias-Carrasco, Maider, et al.
(författare)
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Sexual selection buffers the negative consequences of population fragmentation on adaptive plastic responses to increasing temperatures
- 2024
-
Ingår i: Evolution. - 0014-3820. ; 78:1, s. 86-97
-
Tidskriftsartikel (refereegranskat)abstract
- Whether sexual selection facilitates or hampers the ability to plastically respond to novel environments might depend on population structure, via its effects on sexual interactions and associated fitness payoffs. Using experimentally evolved lines of the seed beetle Callosobruchus maculatus, we tested whether individuals evolving under different sexual selection (monogamy vs. polygamy) and population spatial structure (metapopulation vs. undivided populations) treatments differed in their response across developmental thermal conditions (control, hot, or stressful) in a range of fitness and fitness-associated traits. We found that individuals from subdivided populations had lower lifetime reproductive success at hot temperatures, but only in lines evolving under relaxed sexual selection, revealing a complex interaction between sexual selection, population structure, and thermal environmental stress on fitness. We also found an effect of population structure on several traits, including fertility and adult emergence success, under exposure to high thermal conditions. Finally, we found a strong negative effect of hot and stressful temperatures on fitness and associated traits. Our results show that population structure can exacerbate the impact of a warming climate, potentially leading to declines in population viability, but that sexual selection can buffer the negative influence of population subdivision on adaptation to warm temperatures.
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| 74. |
- Lifjeld, Jan T., et al.
(författare)
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Rapid sperm length divergence in a polygynandrous passerine: a mechanism of cryptic speciation?
- 2023
-
Ingår i: Evolution; international journal of organic evolution. - 1558-5646. ; 77:11, s. 2352-2364
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Tidskriftsartikel (refereegranskat)abstract
- When populations become geographically isolated, they begin to diverge in various traits and at variable rates. The dynamics of such trait divergences are relevant for understanding evolutionary processes such as local adaptation and speciation. Here we examine divergences in sperm and body structures in a polygynandrous songbird, the alpine accentor (Prunella collaris) between two allopatric high-altitude populations, in Morocco and Spain. The populations diverged around 82,000 years ago, as estimated with a coalescence-based phylogenetic analysis of genome-wide single-nucleotide polymorphisms. We found that birds in the two areas had nonoverlapping sperm lengths, which suggests adaptation to divergent female reproductive tract environments. Sperm length also showed an exceptionally low coefficient of among-male variation, a signal of strong stabilizing selection imposed by sperm competition. The evolutionary rate of sperm length was almost twice the rates for the most divergent morphological traits and more than three times higher than expected from literature data over a similar generational timescale. This rapid evolution of a key reproductive trait has implications for reproductive isolation and ultimately for speciation. Strong selection for different sperm length optima in allopatry predicts conspecific sperm precedence and disruptive selection in sympatry, hence a possible postcopulatory prezygotic barrier to gene flow.
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| 75. |
- Ten Brink, Hanna, et al.
(författare)
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Seasonality and competition select for variable germination behavior in perennials
- 2023
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Ingår i: Evolution; international journal of organic evolution. - 1558-5646. ; 77:8, s. 1791-1805
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Tidskriftsartikel (refereegranskat)abstract
- The occurrence of within-population variation in germination behavior and associated traits such as seed size has long fascinated evolutionary ecologists. In annuals, unpredictable environments are known to select for bet-hedging strategies causing variation in dormancy duration and germination strategies. Variation in germination timing and associated traits is also commonly observed in perennials and often tracks gradients of environmental predictability. Although bet-hedging is thought to occur less frequently in long-lived organisms, these observations suggest a role of bet-hedging strategies in perennials occupying unpredictable environments. We use complementary analytical and evolutionary simulation models of within-individual variation in germination behavior in seasonal environments to show how bet-hedging interacts with fluctuating selection, life-history traits, and competitive asymmetries among germination strategies. We reveal substantial scope for bet-hedging to produce variation in germination behavior in long-lived plants, when "false starts" to the growing season results in either competitive advantages or increased mortality risk for alternative germination strategies. Additionally, we find that lowering adult survival may, in contrast to classic bet-hedging theory, result in less spreading of germination by decreasing density-dependent competition. These models extend insights from bet-hedging theory to perennials and explore how competitive communities may be affected by ongoing changes in climate and seasonality patterns.
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