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  • 1. Abalde, Samuel
    et al.
    Tellgren-Roth, Christian
    Heintz, Julia
    Pettersson, Olga Vinnere
    Jondelius, Ulf
    Stockholm University, Faculty of Science, Department of Zoology, Systematic Zoology.
    The draft genome of the microscopic Nemertoderma westbladi sheds light on the evolution of Acoelomorpha genomes2023In: Frontiers in Genetics, E-ISSN 1664-8021, Vol. 14, article id 1244493Article in journal (Refereed)
    Abstract [en]

    Background: Xenacoelomorpha is a marine clade of microscopic worms that is an important model system for understanding the evolution of key bilaterian novelties, such as the excretory system. Nevertheless, Xenacoelomorpha genomics has been restricted to a few species that either can be cultured in the lab or are centimetres long. Thus far, no genomes are available for Nemertodermatida, one of the group's main clades and whose origin has been dated more than 400 million years ago.Methods: DNA was extracted from a single specimen and sequenced with HiFi following the PacBio Ultra-Low DNA Input protocol. After genome assembly, decontamination, and annotation, the genome quality was benchmarked using two acoel genomes and one Illumina genome as reference. The gene content of three cnidarians, three acoelomorphs, four deuterostomes, and eight protostomes was clustered in orthogroups to make inferences of gene content evolution. Finally, we focused on the genes related to the ultrafiltration excretory system to compare patterns of presence/absence and gene architecture among these clades.Results: We present the first nemertodermatid genome sequenced from a single specimen of Nemertoderma westbladi. Although genome contiguity remains challenging (N50: 60 kb), it is very complete (BUSCO: 80.2%, Metazoa; 88.6%, Eukaryota) and the quality of the annotation allows fine-detail analyses of genome evolution. Acoelomorph genomes seem to be relatively conserved in terms of the percentage of repeats, number of genes, number of exons per gene and intron size. In addition, a high fraction of genes present in both protostomes and deuterostomes are absent in Acoelomorpha. Interestingly, we show that all genes related to the excretory system are present in Xenacoelomorpha except Osr, a key element in the development of these organs and whose acquisition seems to be interconnected with the origin of the specialised excretory system.Conclusion: Overall, these analyses highlight the potential of the Ultra-Low Input DNA protocol and HiFi to generate high-quality genomes from single animals, even for relatively large genomes, making it a feasible option for sequencing challenging taxa, which will be an exciting resource for comparative genomics analyses.

  • 2.
    Acerbi, Alberto
    et al.
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution. Brooklyn College, US.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Regulatory Traits in Cultural Evolution2012In: Proceedings of WiVACE 2012, 2012, p. 1-9Conference paper (Refereed)
    Abstract [en]

    We call "regulatory traits" those cultural traits that are transmitted through cultural interactions and, at the same time, change individual behaviors directly influencing the outcome of future cultural interactions. The cultural dynamics of some of those traits are studied through simple simulations. In particular, we consider the cultural evolution of traits determining the propensity to copy, the number of potential demonstrators from whom one individual may copy, and conformist versus anti conformist attitudes. Our results show that regulatory traits generate peculiar dynamics that may explain complex human cultural phenomena. We discuss how the existence and importance of regulatory traits in cultural evolution impact on the analogy between genetic and cultural evolution and therefore on the possibility of using evolutionary biology inspired models to study human cultural dynamics.

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  • 3.
    Ah-King, Malin
    Stockholm University, Faculty of Humanities, Department of Ethnology, History of Religions and Gender Studies, Gender Studies.
    The Female Turn: How Evolutionary Science Shifted Perceptions About Females2022Book (Refereed)
    Abstract [en]

    This book traces the history of how evolutionary biology transformed its understanding of females from being coy, reserved and sexually passive, to having active sexual strategies and often mating with multiple males. Why did it take so long to discover female active sexual strategies? What prevented some researchers from engaging in sexually active females, and what prompted others to develop this new knowledge?

    The Female Turn provides a global overview of shifting perceptions about females in sexual selection research on a wide range of animals, from invertebrates to primates. Evolutionary biologist and feminist science scholar Malin Ah-King explores this history from a unique interdisciplinary vantage point. Based on extensive knowledge of the scientific literature on sexual selection and in-depth interviews with leading researchers, pioneers and feminist scientists in the field, her analysis engages with key theoretical approaches in gender studies of science. Analyzing the researchers’ scientific interests, theoretical frameworks, specific study animals, technological innovations, methodologies and sometimes feminist insights, reveals how these have shaped conclusions drawn about sex. Thereby, The Female Turn shows how certain researchers gained knowledge about active females whereas others missed, ignored or delayed it – that is, how ignorance was produced.

  • 4.
    Ah-King, Malin
    Stockholm University, Faculty of Humanities, Department of Ethnology, History of Religions and Gender Studies.
    The history of sexual selection research provides insights as to why females are still understudied2022In: Nature Communications, E-ISSN 2041-1723, Vol. 13, article id 6976Article in journal (Refereed)
    Abstract [en]

    While it is widely acknowledged that Darwin’s descriptions of females were gender-biased, gender bias in current sexual selection research is less recognized. An examination of the history of sexual selection research shows prevalent male precedence—that research starts with male-centered investigations or explanations and thereafter includes female-centered equivalents. In comparison, the incidence of female precedence is low. Furthermore, a comparison between the volume of publications focusing on sexual selection in males versus in females shows that the former far outnumber the latter. This bias is not only a historical pattern; sexual selection theory and research are still male-centered—due to conspicuous traits, practical obstacles, and continued gender bias. Even the way sexual selection is commonly defined contributes to this bias. This history provides an illustrative example by which we can learn to recognize biases and identify gaps in knowledge. I conclude with a call for the scientific community to interrogate its own biases and suggest strategies for alleviating biases in this field and beyond.

  • 5.
    Ah-King, Malin
    et al.
    Stockholm University, Faculty of Humanities, Department of Ethnology, History of Religions and Gender Studies. Uppsala University, Sweden; University of California, USA.
    Gowaty, Patricia Adair
    A conceptual review of mate choice: stochastic demography, within-sex phenotypic plasticity, and individual flexibility2016In: Ecology and Evolution, E-ISSN 2045-7758, Vol. 6, no 14, p. 4607-4642Article, review/survey (Refereed)
    Abstract [en]

    Mate choice hypotheses usually focus on trait variation of chosen individuals. Recently, mate choice studies have increasingly attended to the environmental circumstances affecting variation in choosers' behavior and choosers' traits. We reviewed the literature on phenotypic plasticity in mate choice with the goal of exploring whether phenotypic plasticity can be interpreted as individual flexibility in the context of the switch point theorem, SPT (Gowaty and Hubbell ). We found >3000 studies; 198 were empirical studies of within-sex phenotypic plasticity, and sixteen showed no evidence of mate choice plasticity. Most studies reported changes from choosy to indiscriminate behavior of subjects. Investigators attributed changes to one or more causes including operational sex ratio, adult sex ratio, potential reproductive rate, predation risk, disease risk, chooser's mating experience, chooser's age, chooser's condition, or chooser's resources. The studies together indicate that choosiness of potential mates is environmentally and socially labile, that is, induced - not fixed - in the choosy sex with results consistent with choosers' intrinsic characteristics or their ecological circumstances mattering more to mate choice than the traits of potential mates. We show that plasticity-associated variables factor into the simpler SPT variables. We propose that it is time to complete the move from questions about within-sex plasticity in the choosy sex to between- and within-individual flexibility in reproductive decision-making of both sexes simultaneously. Currently, unanswered empirical questions are about the force of alternative constraints and opportunities as inducers of individual flexibility in reproductive decision-making, and the ecological, social, and developmental sources of similarities and differences between individuals. To make progress, we need studies (1) of simultaneous and symmetric attention to individual mate preferences and subsequent behavior in both sexes, (2) controlled for within-individual variation in choice behavior as demography changes, and which (3) report effects on fitness from movement of individual's switch points.

  • 6.
    Ahlenius, Henrik
    Stockholm University, Faculty of Humanities, Department of Philosophy.
    Moral Lessons from Psychology: Contemporary Themes in Psychological Research and their Relevance for Ethical Theory2020Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The thesis investigates the implications for moral philosophy of research in psychology. In addition to an introduction and concluding remarks, the thesis consists of four chapters, each exploring various more specific challenges or inputs to moral philosophy from cognitive, social, personality, developmental, and evolutionary psychology. Chapter 1 explores and clarifies the issue of whether or not morality is innate. The chapter’s general conclusion is that evolution has equipped us with a basic suite of emotions that shape our moral judgments in important ways. Chapter 2 presents and investigates the challenge presented to deontological ethics by Joshua Greene’s so-called dual process theory. The chapter partly agrees with his conclusion that the dual process view neutralizes some common criticisms against utilitarianism founded on deontological intuitions, but also points to avenues left to explore for deontologists. Chapter 3 focuses on Katarzyna de Lazari-Radek and Peter Singer’s suggestion that utilitarianism is less vulnerable to so-called evolutionary debunking than other moral theories. The chapter is by and large critical of their attempt. In the final chapter 4, attention is directed at the issue of whether or not social psychology has shown that people lack stable character traits, and hence that the virtue ethical view is premised on false or tenuous assumptions. Though this so-called situationist challenge at one time seemed like a serious threat to virtue ethics, the chapter argues for a moderate position, pointing to the fragility of much of the empirical research invoked to substantiate this challenge while also suggesting revisions to the virtue ethical view as such.

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  • 7. Allendorf, Fred W.
    et al.
    Berry, Oliver
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology.
    So long to genetic diversity, and thanks for all the fish2014In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 23, no 1, p. 23-25Article in journal (Other academic)
    Abstract [en]

    The world faces a global fishing crisis. Wild marine fisheries comprise nearly 15% of all animal protein in the human diet, but, according to the U.N. Food and Agriculture Organization, nearly 60% of all commercially important marine fish stocks are overexploited, recovering, or depleted (FAO 2012; Fig. 1). Some authors have suggested that the large population sizes of harvested marine fish make even collapsed populations resistant to the loss of genetic variation by genetic drift (e. g. Beverton 1990). In contrast, others have argued that the loss of alleles because of overfishing may actually be more dramatic in large populations than in small ones (Ryman et al. 1995). In this issue, Pinsky & Palumbi (2014) report that overfished populations have approximately 2% lower heterozygosity and 12% lower allelic richness than populations that are not overfished. They also performed simulations which suggest that their estimates likely underestimate the actual loss of rare alleles by a factor of three or four. This important paper shows that the harvesting of marine fish can have genetic effects that threaten the long-term sustainability of this valuable resource.

  • 8.
    Ament-Velásquez, Sandra Lorena
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Gilchrist, Ciaran
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Rêgo, Alexandre
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Bendixsen, Devin P.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Brice, Claire
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Grosse-Sommer, Julie Michelle
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics. Maastricht University, The Netherlands.
    Rafati, Nima
    Stelkens, Rike
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    The Dynamics of Adaptation to Stress from Standing Genetic Variation and de novo Mutations 2022In: Molecular biology and evolution, ISSN 0737-4038, E-ISSN 1537-1719, Vol. 39, no 11, article id msac242Article in journal (Refereed)
    Abstract [en]

    Adaptation from standing genetic variation is an important process underlying evolution in natural populations, but we rarely get the opportunity to observe the dynamics of fitness and genomic changes in real time. Here, we used experimental evolution and Pool-Seq to track the phenotypic and genomic changes of genetically diverse asexual populations of the yeast Saccharomyces cerevisiae in four environments with different fitness costs. We found that populations rapidly and in parallel increased in fitness in stressful environments. In contrast, allele frequencies showed a range of trajectories, with some populations fixing all their ancestral variation in <30 generations and others maintaining diversity across hundreds of generations. We detected parallelism at the genomic level (involving genes, pathways, and aneuploidies) within and between environments, with idiosyncratic changes recurring in the environments with higher stress. In particular, we observed a tendency of becoming haploid-like in one environment, whereas the populations of another environment showed low overall parallelism driven by standing genetic variation despite high selective pressure. This work highlights the interplay between standing genetic variation and the influx of de novo mutations in populations adapting to a range of selective pressures with different underlying trait architectures, advancing our understanding of the constraints and drivers of adaptation. 

  • 9.
    Andersson, Anastasia
    Stockholm University, Faculty of Science, Department of Zoology.
    Hidden biodiversity in an alpine freshwater top predator: Existence, characteristics, and temporal dynamics of cryptic, sympatric brown trout populations2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Intraspecific genetic diversity is imperative to the survival of species in a changing environment, and it plays a vital role in ecosystem function. Since this type of diversity can be difficult to detect it is sometimes referred to as “hidden biodiversity”. When separate and genetically distinct populations of the same species coexist within the same habitat, without apparent barriers to migration and obvious phenotypic divergence, this form of hidden biodiversity is called cryptic sympatry. Knowledge of cryptic sympatry is limited, however, and the aim of this thesis is to increase our understanding of this phenomenon by focusing on a species group where several cases of sympatry have been documented – the salmonids.

    Using the brown trout (Salmo trutta) as a model, I characterized two previously reported cases of cryptic sympatry occurring in small Swedish alpine lakes with respect to both phenotypic and genetic characteristics. I explored the hypothesis that cryptic sympatry is more common than currently recognized by reviewing literature documenting sympatry, as well as by assessing the statistical power to detect sympatric populations with varying degrees of divergence using commonly applied sample sizes for loci and individuals. Further, I performed a large-scale search for sympatric populations in alpine lakes in central Sweden.

    I found that cryptic, sympatric populations can coexist while apparently utilizing the same food resources and exhibiting the same adaptive plasticity to their shared environment (Paper I). In one of the empirical cases there were indications that the populations used different creeks for spawning, suggesting that segregation in spawning location contributes to the maintenance of sympatry (Paper II). Further, I found that differences between cryptic, sympatric populations of the same lake may be large with respect to levels of genetic diversity, inbreeding, and connectivity with populations in nearby lakes (Papers II and III). 

    I found support for the hypothesis that cryptic sympatry is more common than generally acknowledged (Papers IV and V). In the literature, cryptic sympatry is rarely reported and typically associated with higher divergence levels than between sympatric populations that differ phenotypically. My results suggest that this to a large extent may be due to limited statistical power when commonly used sample sizes in terms of individuals and loci are applied and the amount of divergence between populations is small (Paper IV). Cryptic sympatry was observed in over 40% of the screened localities (27 lakes), and was shown to be temporally stable over at least 40 years (Paper V).

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    Hidden biodiversity in an alpine freshwater top predator: Existence, characteristics, and temporal dynamics of cryptic, sympatric brown trout populations
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  • 10.
    Andersson, Anastasia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Karlsson, Sten
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Laikre, Linda
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Mapping and monitoring genetic diversity in brown trout population systems in alpine lakes by applying newly proposed indicatorsManuscript (preprint) (Other academic)
  • 11.
    Bachmann, Jörg A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Tedder, Andrew
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Genete, Mathieu
    Ferreira de Carvalho, Julie
    Castric, Vincent
    Slotte, Tanja
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Evolutionary stability of genetic dominance in the Brassicaceae self-incompatibility systemManuscript (preprint) (Other academic)
    Abstract [en]

    The question of whether dominance-recessivity relationships between associated alleles in a diploid genotype can evolve independently from the activity of the gene products encoded has been a hot topic in evolutionary genetics throughout the 20th century. In hermaphroditic plants of the Brassicaceae family, the self-incompatibility locus (S-locus) confers the ability to recognize and reject self-pollen. Dominance relationships between self-incompatibility alleles (S-alleles) in pollen are governed by small RNA (sRNA) transcriptional regulators produced by dominant S-alleles and their target sites on recessive S-alleles. These regulators and their target sites segregate together with but are distinct from the genes encoding self-recognition specificities themselves, providing the opportunity for dominance to evolve independently from the recognition specificities. Dominance interactions between the many segregating S-alleles have been described in the distantly related Arabidopsis and Brassica, but little is known about the evolutionary stability of the dominance networks given that divergent sets of S-alleles are segregating in these two genera. In this study, we take advantage of the extensive trans-specific sharing of S-haplotypes between the self-incompatible species Capsella grandiflora and Arabidopsis halleri to investigate the conservation of S-locus dominance relationships across their approximately 8 million years of divergence. For this purpose, we use a combination of controlled crosses and full-length long-read sequencing of S-haplotypes. We find that the dominance network among six C. grandiflora S-alleles has a largely parallel structure to that among their orthologous S-alleles in A. halleri. We test the theoretical prediction that dominant S-alleles should be found at lower population frequencies using a large sample of a natural C. grandiflora population. Finally, we test whether dominant C. grandiflora S-alleles show increased accumulation of repeats (TEs) than recessive S-alleles, as expected due to their lower chance of recombination and lower effective population sizes. Our results contribute to an improved understanding of the maintenance of dominance relationships at loci under balancing selection.

  • 12.
    Bachmann, Jörg Alexander
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Evolutionary consequences of dominance at the Brassicaceae self-incompatibility locus2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Self-incompatibility (SI) is a genetic mechanism that allows plants to enforce outcrossing by rejecting self-pollen and pollen from close relatives. In the Brassicaceae, SI is sporophytic and controlled by the self-incompatibility locus (S-locus). The S-locus harbors two tightly linked genes SRK and SCR, which encode the female and male SI specificity determinants, respectively. S-locus heterozygotes often only express the S-specificity of the more dominant allele, and at the pollen level such dominance relationships are mediated by small RNAs (sRNAs). The S-locus is thus an example of a locus under strong balancing selection, where dominance modifiers have evolved.

    In this thesis, I investigate the consequences of S-locus dominance for plant mating system evolution and allopolyploid speciation. I further investigate evolutionary conservation and sequence-level effects of dominance relationships among S-alleles. For this purpose, I used the crucifer genus Capsella as a model system.

    First, I demonstrated that targeted long-read sequencing results in structurally accurate assemblies of full-length S-haplotype sequences, and that indel errors in such assemblies can be corrected using short reads. Second, I investigated the genetic basis of loss of SI, the first step in the evolution of self-fertilisation, in the self-compatible (SC) Capsella orientalis. I found that loss of SI was dominant and mapped to the S-locus, where C. orientalis harbored a fixed coding frameshift deletion in SCR that is likely to lead to loss of male specificity. I further identified a sRNA-based dominance modifier that is associated with dominant suppression of recessive SCR alleles. Taken together, these results suggest that loss of SI in C. orientalis involved a dominant S-haplotype, suggesting that dominant haplotypes may be favored under conditions that select for loss of SI. Third, I show that a dominant S-haplotype may also have contributed to the shift to SC in the widespread allotetraploid Capsella bursa-pastoris. Fourth, I showed that dominance relationships at the S-locus are largely conserved between the SI outcrossing species C. grandiflora and Arabidopsis halleri which diverged ~8 Mya. I also found that dominant S-haplotypes accumulate more transposable elements than recessive S-haplotypes, in line with expected sequence-level consequences of S-locus dominance. In sum, this thesis provides new insights into the broad conservation of dominance hierarchies at the Brassicaceae S-locus, and the role of dominant S-alleles in allopolyploid speciation and plant mating system shifts.

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  • 13.
    Berckx, Fede
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    To be together or not to be together: Ca. 100 million years of evolutionary history of the earliest divergent Frankia clade2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Root nodule symbiosis evolved ca. 100 Mya between a nitrogen-fixing bacterium and the common ancestor to the Fabales, Fagales, Rosales, and Cucurbitales plant orders. Over time the majority of the lineages derived from this ancestor lost their symbiotic capability. While extant symbiotic members found in the Fabales order (legumes) all engage in symbiosis with rhizobia, extant symbiotic members of the latter three plant orders are referred to as actinorhizal plants. These engage in symbiosis with Frankia.

    Frankia is a genus of soil actinobacteria, which can be split into four phylogenetically distinct clades. The earliest divergent symbiotic clade, Frankia cluster-2, encompasses strains that have a broad host range and could not be cultured in vitro thus far with two exceptions. Based on Frankia enriched meta-genomes from whole nodules collected at different locations across the globe, it is clear there is very little diversity of Frankia cluster-2 in continental Eurasia, spanning from France to Japan. These strains are also closely related to strains found in North America. However, very little is known about strains occurring in the islands in the Pacific Ocean and the southern hemisphere.

    In short, this thesis aimed to investigate the biodiversity of the earliest divergent symbiotic Frankia clade and to understand how Frankia spread across the globe (Study 1 and Study 2). From nodules collected in study 1, a novel Streptomyces species was identified and declared (Study 3). The thesis also aimed to study genetic changes within Frankia cluster-2 which might be associated with their endosymbiotic lifestyle and low saprotrophic potential (Study 4 and Study 5).

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  • 14.
    Berckx, Fede
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nguyen, Thanh Van
    Bandong, Cyndi Mae
    Lin, Hsiao-Han
    Yamanaka, Takashi
    Katayama, Sae
    Wibberg, Daniel
    Blom, Jochen
    Kalinowski, Jörn
    Tateno, Masaki
    Simbahan, Jessica
    Liu, Chi-Te
    Brachmann, Andreas
    Pawlowski, Katharina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    A tale of two lineages: how the strains of the earliest divergent symbiotic Frankia clade spread over the worldManuscript (preprint) (Other academic)
  • 15.
    Berckx, Fede
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nguyen, Thanh Van
    Hilker, Rolf
    Wibberg, Daniel
    Battenberg, Kai
    Berry, Alison
    Kalinowski, Jörn
    Pawlowski, Katharina
    Genome reduction in the earliest divergent Frankia clade is responsible for its low saprotrophic capabilitiesManuscript (preprint) (Other academic)
  • 16.
    Berckx, Fede
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Wibberg, Daniel
    Brachmann, Andreas
    Wall, Luis Gabriel
    Kalinowski, Jörn
    Pawlowski, Katharina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    The earliest divergent Frankia from the Gondwana continentManuscript (preprint) (Other academic)
  • 17.
    Berger, David
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Olofsson, Martin
    Stockholm University, Faculty of Science, Department of Zoology.
    Gotthard, Karl
    Stockholm University, Faculty of Science, Department of Zoology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Friberg, Magne
    Stockholm University, Faculty of Science, Department of Zoology.
    Ecological Constraints on Female Fitness in a Phytophagous Insect2012In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 180, no 4, p. 464-480Article in journal (Refereed)
    Abstract [en]

    Although understanding female reproduction is crucial for population demography, determining how and to what relative extent it is constrained by different ecological factors is complicated by difficulties in studying the links between individual behavior, life history, and fitness in nature. We present data on females in a natural population of the butterfly Leptidea sinapis. These data were combined with climate records and laboratory estimates of life-history parameters to predict the relative impact of different ecological constraints on female fitness in the wild. Using simulation models, we partitioned effects of male courtship, host plant availability, and temperature on female fitness. Results of these models indicate that temperature is the most constraining factor on female fitness, followed by host plant availability; the short-term negative effects of male courtship that were detected in the field study were less important in models predicting female reproductive success over the entire life span. In the simulations, females with more reproductive reserves were more limited by the ecological variables. Reproductive physiology and egg-laying behavior were therefore predicted to be co-optimized but reach different optima for females of different body sizes; this prediction is supported by the empirical data. This study thus highlights the need for studying behavioral and life-history variation in orchestration to achieve a more complete picture of both demographic and evolutionary processes in naturally variable and unpredictable environments.

  • 18.
    Bolinder, Kristina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Pollen and pollination in Ephedra (Gnetales)2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Ephedra (Gnetales) is a gymnosperm genus with a long evolutionary history; the first dispersed pollen grains with affinity to the group are known already from the Permian. This thesis focuses on the evolutionary history of the group and different aspects of its pollination mechanisms. Despite the limited number of extant species of the genus (50-60), and a low morphological and genetic divergence among species, there is variation in pollination syndrome in the genus. The prevailing state in Ephedra, and most gymnosperms, is wind pollination. It is therefore surprising that one species, E. foeminea, is insect-pollinated. Together with co-workers I documented the pollination syndromes of E. foeminea and a sympatric species, E. distachya, based on long term field experiments in north-eastern Greece and aerodynamic investigations and calculations. Placing the results into an evolutionary framework reveals that the insect-pollinated species E. foeminea is sister to the remaining (mostly wind-pollinated) genus, and indicates that insect pollination is the ancestral state in the Gnetales. During the course of evolution of the group there has been a shift to wind pollination, which may have played a crucial role for the diversification of the crown group in the Paleogene. Pollination biology is often correlated with the morphology of the pollen such that pollen grains of anemophilous plants are small with a smooth surface, whereas pollen grains of entomophilous plants are larger with an ornamented surface and a covering of pollenkitt. The pollen morphology of Ephedra can be broadly divided into two types: an ancestral type with an unbranched pseudosulcus between each pair of plicae, and a derived type with a branched pseudosulcus between each pair of plicae. Further, the pollen morphology and ultrastructure of the pollen wall in Ephedra are to some degree correlated with the pollination syndrome and capability of long distance dispersal. Pollen of E. foeminea has a denser ultrastructure, as a result a higher settling velocity and is therefore capable of flying shorter distances than does pollen of the anemophilous E. distachya, and other investigated anemophilous species that show a more spacious ultrastructure of the pollen grain. These results can be useful in the reconstruction of the pollination mechanism of extinct taxa of the Ephedra-lineage in the future.

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  • 19.
    Braga, Mariana P.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Guimarães Jr, Paulo R.
    Wheat, Christopher W.
    Stockholm University, Faculty of Science, Department of Zoology.
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Unifying host-associated diversification processes using butterfly-plant networks2018In: Nature Communications, E-ISSN 2041-1723, Vol. 9, article id 5155Article in journal (Refereed)
    Abstract [en]

    Explaining the exceptional diversity of herbivorous insects is an old problem in evolutionary ecology. Here we focus on the two prominent hypothesised drivers of their diversification, radiations after major host switch or variability in host use due to continuous probing of new hosts. Unfortunately, current methods cannot distinguish between these hypotheses, causing controversy in the literature. Here we present an approach combining network and phylogenetic analyses, which directly quantifies support for these opposing hypotheses. After demonstrating that each hypothesis produces divergent network structures, we then investigate the contribution of each to diversification in two butterfly families: Pieridae and Nymphalidae. Overall, we find that variability in host use is essential for butterfly diversification, while radiations following colonisation of a new host are rare but can produce high diversity. Beyond providing an important reconciliation of alternative hypotheses for butterfly diversification, our approach has potential to test many other hypotheses in evolutionary biology.

  • 20.
    Braga, Mariana P.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Landis, Michael
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Ronquist, Fredrik
    Bayesian analysis of host repertoire evolutionManuscript (preprint) (Other academic)
  • 21.
    Braga, Mariana P.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Landis, Michael
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Ronquist, Fredrik
    Evolution of butterfly-plant networks revealed by Bayesian inference of host repertoireManuscript (preprint) (Other academic)
  • 22.
    Braga, Mariana Pires
    Stockholm University, Faculty of Science, Department of Zoology.
    Evolution of host repertoires and the diversification of butterflies2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    All herbivorous insects are specialized to some extent to their host plants, but the level of specialization varies greatly. Insect-plant coevolution is often invoked to explain the large diversity of herbivorous insects, but the role of specialization during diversification is still controversial. Although well-studied, our understanding of the evolution of species interactions is still improving, and recent theoretical developments have highlighted the role of generalization (via colonization of new hosts) on diversification. In this thesis, various approaches are combined for a detailed study of the origins of macroevolutionary patterns of host use and butterfly diversity. Chapter I provides a mechanistic basis for such patterns through simulations of lineages evolved in silico. By separating the effects of the number of hosts used by a parasite lineage and the diversity of resources they encompass, we found that resource diversity, rather than host range per se, was the main driver of parasite species richness in both simulated and empirical systems. In Chapter II, we combined network and phylogenetic analyses to quantify support for the two main hypothesized drivers of diversification of herbivorous insects. Based on analyses of two butterfly families, Nymphalidae and Pieridae, we found that variability in host use is essential for diversification, while radiation following the colonization of a new host is rare but can produce high diversity. We then reconciled the two alternative hypotheses into a unified process of host-associated diversification where continuous probing of new hosts and retention of the ability to use hosts colonized in the past are the main factors shaping butterfly-plant networks. While network analysis is a powerful tool for investigating patterns of interaction, other methods are necessary to directly test the mechanisms generating the observed patterns. Therefore, in Chapter III we describe a model of host repertoire evolution we developed for Bayesian inference of evolution of host-parasite interactions. The approach was validated with both simulated and empirical data sets. Finally, in Chapter IV we used the method described in Chapter III to explicitly test the predictions made in Chapter II about the evolution of butterfly-plant networks. We found direct evidence for the role of expansion of fundamental host repertoire and phylogenetic conservatism as important drivers of host repertoire evolution. Thus, using three different approaches, we found overall support for the idea that variation in host use accumulated over evolutionary time is essential for butterfly diversification.

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  • 23.
    Bukontaite, Rasa
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden.
    Miller, Kelly B.
    Bergsten, Johannes
    The utility of CAD in recovering Gondwanan vicariance events and the evolutionary history of Aciliini (Coleoptera: Dytiscidae)2014In: BMC Evolutionary Biology, E-ISSN 1471-2148, Vol. 14, p. 5-Article in journal (Refereed)
    Abstract [en]

    Background: Aciliini presently includes 69 species of medium-sized water beetles distributed on all continents except Antarctica. The pattern of distribution with several genera confined to different continents of the Southern Hemisphere raises the yet untested hypothesis of a Gondwana vicariance origin. The monophyly of Aciliini has been questioned with regard to Eretini, and there are competing hypotheses about the intergeneric relationship in the tribe. This study is the first comprehensive phylogenetic analysis focused on the tribe Aciliini and it is based on eight gene fragments. The aims of the present study are: 1) to test the monophyly of Aciliini and clarify the position of the tribe Eretini and to resolve the relationship among genera within Aciliini, 2) to calibrate the divergence times within Aciliini and test different biogeographical scenarios, and 3) to evaluate the utility of the gene CAD for phylogenetic analysis in Dytiscidae. Results: Our analyses confirm monophyly of Aciliini with Eretini as its sister group. Each of six genera which have multiple species are also supported as monophyletic. The origin of the tribe is firmly based in the Southern Hemisphere with the arrangement of Neotropical and Afrotropical taxa as the most basal clades suggesting a Gondwana vicariance origin. However, the uncertainty as to whether a fossil can be used as a stem-or crowngroup calibration point for Acilius influenced the result: as crowngroup calibration, the 95% HPD interval for the basal nodes included the geological age estimate for the Gondwana break-up, but as a stem group calibration the basal nodes were too young. Our study suggests CAD to be the most informative marker between 15 and 50 Ma. Notably, the 2000 bp CAD fragment analyzed alone fully resolved the tree with high support. Conclusions: 1) Molecular data confirmed Aciliini as a monophyletic group. 2) Bayesian optimizations of the biogeographical history are consistent with an influence of Gondwana break-up history, but were dependent on the calibration method. 3) The evaluation using a method of phylogenetic signal per base pair indicated Wnt and CAD as the most informative of our sampled genes.

  • 24. Burger, Joep M. S.
    et al.
    Buechel, Séverine D.
    University of Lausanne, Switzerland.
    Kawecki, Tadeusz J.
    Dietary restriction affects lifespan but not cognitive aging in Drosophila melanogaster2010In: Aging Cell, ISSN 1474-9718, E-ISSN 1474-9726, Vol. 9, no 3, p. 327-335Article in journal (Refereed)
    Abstract [en]

    Dietary restriction extends lifespan in a wide variety of animals, including Drosophila, but its relationship to functional and cognitive aging is unclear. Here, we study the effects of dietary yeast content on fly performance in an aversive learning task (association between odor and mechanical shock). Learning performance declined at old age, but 50-day-old dietary-restricted flies learned as poorly as equal-aged flies maintained on yeast-rich diet, even though the former lived on average 9 days (14%) longer. Furthermore, at the middle age of 21 days, flies on low-yeast diets showed poorer short-term (5 min) memory than flies on rich diet. In contrast, dietary restriction enhanced 60-min memory of young (5 days old) flies. Thus, while dietary restriction had complex effects on learning performance in young to middle-aged flies, it did not attenuate aging-related decline of aversive learning performance. These results are consistent with the hypothesis that, in Drosophila, dietary restriction reduces mortality and thus leads to lifespan extension, but does not affect the rate with which somatic damage relevant for cognitive performance accumulates with age.

  • 25. Burnett, Hamish A.
    et al.
    Bieker, Vanessa C.
    Le Moullec, Mathilde
    Peeters, Bart
    Rosvold, Jørgen
    Ønvik Pedersen, Åshild
    Dalén, Love
    Stockholm University, Faculty of Science, Department of Zoology. Centre for Palaeogenetics, Sweden; Swedish Museum of Natural History, Sweden.
    Loe, Leif Egil
    Jensen, Henrik
    Hansen, Brage B.
    Martin, Michael D.
    Contrasting genomic consequences of anthropogenic reintroduction and natural recolonization in high-arctic wild reindeer2023In: Evolutionary Applications, E-ISSN 1752-4571, Vol. 16, no 9, p. 1531-1548Article in journal (Refereed)
    Abstract [en]

    Anthropogenic reintroduction can supplement natural recolonization in reestablishing a species' distribution and abundance. However, both reintroductions and recolonizations can give rise to founder effects that reduce genetic diversity and increase inbreeding, potentially causing the accumulation of genetic load and reduced fitness. Most current populations of the endemic high-arctic Svalbard reindeer (Rangifer tarandus platyrhynchus) originate from recent reintroductions or recolonizations following regional extirpations due to past overharvesting. We investigated and compared the genomic consequences of these two paths to reestablishment using whole-genome shotgun sequencing of 100 Svalbard reindeer across their range. We found little admixture between reintroduced and natural populations. Two reintroduced populations, each founded by 12 individuals around four decades (i.e. 8 reindeer generations) ago, formed two distinct genetic clusters. Compared to the source population, these populations showed only small decreases in genome-wide heterozygosity and increases in inbreeding and lengths of runs of homozygosity. In contrast, the two naturally recolonized populations without admixture possessed much lower heterozygosity, higher inbreeding and longer runs of homozygosity, possibly caused by serial population founder effects and/or fewer or more genetically related founders than in the reintroduction events. Naturally recolonized populations can thus be more vulnerable to the accumulation of genetic load than reintroduced populations. This suggests that in some organisms even small-scale reintroduction programs based on genetically diverse source populations can be more effective than natural recolonization in establishing genetically diverse populations. These findings warrant particular attention in the conservation and management of populations and species threatened by habitat fragmentation and loss. 

  • 26.
    Caputo, Andrea
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Genomic and morphological diversity of marine planktonic diatom-diazotroph associations: a continuum of integration and diversification through geological time2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Symbioses between eukaryotes and nitrogen (N2)-fixing cyanobacteria (or diazotrophs) are quite common in the plankton community. A few genera of diatoms (Bacillariophyceae) such as Rhizosolenia, Hemiaulus and Chaetoceros are well known to form symbioses with the heterocystous diazotrophic cyanobacteria Richelia intracellularis and Calothrix rhizosoleniae. The latter are also called diatom-diazotroph associations, or DDAs. Up to now, the prokaryotic partners have been morphologically and genetically characterized, and the phylogenetic reconstruction of the well conserved nifH gene (encodes for the nitrogenase enzyme) placed the symbionts in 3 clusters based on their host-specificity, i.e. het-1 (Rhizosolenia-R. intracellularis), het-2 (Hemiaulus-R. intracellularis), and het-3 (Chaetoceros-C- rhizosoleniae). Conversely, the diatom-hosts, major representative of the phytoplankton community and crucial contributors to the carbon (C) biogeochemical cycle, have been understudied.

    The first aim of this thesis was to genetically and morphologically characterize the diatom-hosts, and to reconstruct the evolutionary background of the partnerships and the symbiont integration in the host. The molecular-clock analysis reconstruction showed the ancient appearance of the DDAs, and the traits characterizing the ancestors. In addition, diatom-hosts bearing internal symbionts (with more eroded draft genomes) appeared earlier than diatom-hosts with external symbionts. Finally a blast survey highlighted a broader distribution of the DDAs than expected.

    The second aim of this thesis was to compare genetic and physiological characteristics of the DDAs symbionts with the other eukaryote-diazotroph symbiosis, i.e. prymnesiophyte-UCYN-A (or Candidatus Atelocyanobacterium thalassa). The genome comparison highlighted more genes for transporters in het-3 (external symbiont) and in the UCYN-A based symbiosis, suggesting that symbiont location might be relevant also for metabolic exchanges and interactions with the host and/or environment. Moreover, a summary of methodological biases that brought to an underestimation of the DDAs is reported.

    The third aim of this thesis was to determine the distribution of the DDAs in the South Pacific Ocean using a quantitative polymerase chain reaction (qPCR) approach and to outline the environmental drivers of such distribution. Among the het-groups, het-1 was the most abundant/detected and co-occurred with the other 2 symbiotic strains, all responding similarly to the influence of abiotic factors, such as temperature and salinity (positive and negative correlation, respectively). Globally, Trichodesmium dominated the qPCR detections, followed by UCYN-B. UCYN-A phylotypes (A-1, A-2) were detected without their proposed hosts, for which new oligonucleotides were designed. The latter suggested a facultative symbiosis. Finally, microscopy observations of the het-groups highlighted a discrepancy with the qPCR counts (i.e. the former were several order of magnitudes lower), leading to the idea of developing a new approach to quantify the DDAs.  

    The fourth aim of this thesis was to develop highly specific in situ hybridization assays (CARD-FISH) to determine the presence of alternative life-stages and/or free-living partners. The new assays were applied to samples collected in the South China Sea and compared with abundance estimates from qPCR assays for the 3 symbiotic strains. Free-living cells were indeed detected along the transect, mainly at deeper depths. Free-living symbionts had two morphotypes: trichomes and single-cells. The latter were interpreted as temporary life-stages. Consistent co-occurrence of the 3 het-groups was also found in the SCS and application of a SEM model predicted positive interactions between the het groups. We interpreted the positive interaction as absence of intra-specific competition, and consistent with the previous study, temperature and salinity were predicted as major drivers of the DDAs distribution.

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  • 27. Conroy-Beam, Daniel
    et al.
    Roney, James R.
    Lukaszewski, Aaron W.
    Buss, David M.
    Asao, Kelly
    Sorokowska, Agnieszka
    Sorokowski, Piotr
    Aavik, Toivo
    Akello, Grace
    Alhabahba, Mohammad Madallh
    Alm, Charlotte
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Personality, Social and Developmental Psychology.
    Amjad, Naumana
    Anjum, Afifa
    Atama, Chiemezie S.
    Duyar, Derya Atamturk
    Ayebare, Richard
    Batres, Carlota
    Bendixen, Mons
    Bensafia, Aicha
    Bertoni, Anna
    Bizumic, Boris
    Boussena, Mahmoud
    Butovskaya, Marina
    Can, Seda
    Cantarero, Katarzyna
    Carrier, Antonin
    Cetinkaya, Hakan
    Croy, Ilona
    Maria Cueto, Rosa
    Czub, Marcin
    Donato, Silvia
    Dronova, Daria
    Dural, Seda
    Duyar, Izzet
    Ertugrul, Berna
    Espinosa, Agustin
    Estevan, Ignacio
    Esteves, Carla Sofia
    Fang, Luxi
    Frackowiak, Tomasz
    Garduno, Jorge Contreras
    Ugalde Gonzalez, Karina
    Guemaz, Farida
    Gyuris, Petra
    Halamova, Maria
    Herak, Iskra
    Horvat, Marina
    Hromatko, Ivana
    Hui, Chin-Ming
    Iafrate, Raffaella
    Jaafar, Jas Laile
    Jiang, Feng
    Kafetsios, Konstantinos
    Kavcic, Tina
    Kennair, Leif Edward Ottesen
    Kervyn, Nicolas
    Truong, Thi
    Khilji, Imran Ahmed
    Kobis, Nils C.
    Hoang, Moc
    Lang, Andras
    Lennard, Georgina R.
    Leon, Ernesto
    Lindholm, Torun
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Personality, Social and Developmental Psychology.
    Trinh, Thi
    Lopez, Giulia
    Nguyen, Van
    Mailhos, Alvaro
    Manesi, Zoi
    Martinez, Rocio
    McKerchar, Sarah L.
    Mesko, Norbert
    Misra, Girishwar
    Monaghan, Conal
    Mora, Emanuel C.
    Moya-Garofano, Alba
    Musil, Bojan
    Natividade, Jean Carlos
    Niemczyk, Agnieszka
    Nizharadze, George
    Oberzaucher, Elisabeth
    Oleszkiewicz, Anna
    Omar-Fauzee, Mohd Sofian
    Onyishi, Ike E.
    Ozener, Baris
    Pagani, Ariela Francesca
    Pakalniskiene, Vilmante
    Parise, Miriam
    Pazhoohi, Farid
    Pisanski, Annette
    Pisanski, Katarzyna
    Ponciano, Edna
    Popa, Camelia
    Prokop, Pavol
    Rizwan, Muhammad
    Sainz, Mario
    Salkicevic, Svjetlana
    Sargautyte, Ruta
    Sarmany-Schuller, Ivan
    Schmehl, Susanne
    Sharad, Shivantika
    Siddiqui, Razi Sultan
    Simonetti, Franco
    Stoyanova, Stanislava Yordanova
    Tadinac, Meri
    Correa Varella, Marco Antonio
    Vauclair, Christin-Melanie
    Diego Vega, Luis
    Widarini, Dwi Ajeng
    Yoo, Gyesook
    Zatkova, Marta
    Zupancic, Maja
    Assortative mating and the evolution of desirability covariation2019In: Evolution and human behavior, ISSN 1090-5138, E-ISSN 1879-0607, Vol. 40, no 5, p. 479-491Article in journal (Refereed)
    Abstract [en]

    Mate choice lies dose to differential reproduction, the engine of evolution. Patterns of mate choice consequently have power to direct the course of evolution. Here we provide evidence suggesting one pattern of human mate choice-the tendency for mates to be similar in overall desirability-caused the evolution of a structure of correlations that we call the d factor. We use agent-based models to demonstrate that assortative mating causes the evolution of a positive manifold of desirability, d, such that an individual who is desirable as a mate along any one dimension tends to be desirable across all other dimensions. Further, we use a large cross-cultural sample with n = 14,478 from 45 countries around the world to show that this d-factor emerges in human samples, is a cross-cultural universal, and is patterned in a way consistent with an evolutionary history of assortative mating. Our results suggest that assortative mating can explain the evolution of a broad structure of human trait covariation.

  • 28.
    Corral López, Alberto
    Stockholm University, Faculty of Science, Department of Zoology.
    The link between brain size, cognitive ability, mate choice and sexual behaviour in the guppy (Poecilia reticulata)2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Competition over access for mates has led to the evolution of many striking examples of morphological traits and behaviour in animals. The rapid development of the sexual selection field in recent decades have dramatically advanced our understanding of what traits make individuals more successful in attracting mates and how preferences for mates evolve over time. However, till now, research in this field has put less emphasis on the mechanisms that underlie variation in mate choice and sexual behaviour. Cognitive processes could potentially be key drivers of individual variation in mating preferences and sexual behaviours and therefore deserve further investigation. In this thesis, I used guppies artificially selected for relative brain size as the model system to study the association between brain size, cognitive ability and various aspects of mate choice. Previous studies in this model system showed that large-brained individuals of both sexes outperformed small-brained individuals in cognitive tests. Here I quantified their sexual behaviours and mating preferences to provide novel empirical data concerning the association between brain size, cognitive ability and sexual selection. In dichotomous choice preference tests based on visual cues, comparisons between large-brained and small-brained guppies showed important differences in their assessment of mate quality. These results are not driven by pre-existing visual biases caused by the artificial selection since further investigation of the visual capacity of these fish detected no differences between large-brained and small-brained individuals in their sensitivity to colour or in their capacity to resolve spatial detail. I also quantified sexual behaviour in male guppies artificially selected for relative brain size and found no difference in the behaviours of large-brained and small-brained males in a single male-single female non-competitive scenario. On the contrary, in a more complex social setting I found a reduction in large-brained males in the rate of courtship towards females and dominance displays towards other males when exposed to different degrees of predation threat and different numbers of male competitors. However, this reduction in behavioural intensity did not result in a lower access to copulation with females for large-brained males. I likewise evaluated female sexual behaviour and found that large-brained females had higher behavioural flexibility such that they decreased their receptiveness towards males more strongly under higher levels of predation threat. Together, these results provide novel empirical evidence that brain size and cognitive ability are tightly linked to mating preferences and sexual behaviours. These findings suggest that brain size and cognitive ability might be important mechanisms behind variation in mating preferences and in sexually selected traits across and within species.

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  • 29.
    Corral-López, Alberto
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Bloch, Natasha I.
    Kotrschal, Alexander
    Stockholm University, Faculty of Science, Department of Zoology.
    van der Bijl, Wouter
    Stockholm University, Faculty of Science, Department of Zoology.
    Buechel, Severine D.
    Stockholm University, Faculty of Science, Department of Zoology.
    Mank, Judith E.
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology.
    Female brain size affects the assessment of male attractiveness during mate choice2017In: Science Advances, E-ISSN 2375-2548, Vol. 3, no 3, article id e1601990Article in journal (Refereed)
    Abstract [en]

    Mate choice decisions are central in sexual selection theory aimed to understand how sexual traits evolve and their role in evolutionary diversification. We test the hypothesis that brain size and cognitive ability are important for accurate assessment of partner quality and that variation in brain size and cognitive ability underlies variation in mate choice. We compared sexual preference in guppy female lines selected for divergence in relative brain size, which we have previously shown to have substantial differences in cognitive ability. In a dichotomous choice test, large-brained and wild-type females showed strong preference for males with color traits that predict attractiveness in this species. In contrast, small-brained females showed no preference for males with these traits. In-depth analysis of optomotor response to color cues and gene expression of key opsins in the eye revealed that the observed differences were not due to differences in visual perception of color, indicating that differences in the ability to process indicators of attractiveness are responsible. We thus provide the first experimental support that individual variation in brain size affects mate choice decisions and conclude that differences in cognitive ability may be an important underlying mechanism behind variation in female mate choice.

  • 30.
    Corral-López, Alberto
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology. University of British Columbia, Canada; Uppsala University, Sweden.
    Bloch, Natasha I.
    van der Bijl, Wouter
    Cortazar-Chinarro, Maria
    Szorkovszky, Alexander
    Kotrschal, Alexander
    Darolti, Iulia
    Buechel, Severine D.
    Romenskyy, Maksym
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Mank, Judith E.
    Functional convergence of genomic and transcriptomic architecture underlies schooling behaviour in a live-bearing fish2023In: Nature Ecology & Evolution, E-ISSN 2397-334XArticle in journal (Refereed)
    Abstract [en]

    The organization and coordination of fish schools provide a valuable model to investigate the genetic architecture of affiliative behaviours and dissect the mechanisms underlying social behaviours and personalities. Here we used replicate guppy selection lines that vary in schooling propensity and combine quantitative genetics with genomic and transcriptomic analyses to investigate the genetic basis of sociability phenotypes. We show that consistent with findings in collective motion patterns, experimental evolution of schooling propensity increased the sociability of female, but not male, guppies when swimming with unfamiliar conspecifics. This finding highlights a relevant link between coordinated motion and sociability for species forming fission–fusion societies in which both group size and the type of social interactions are dynamic across space and time. We further show that alignment and attraction, the two major traits forming the sociability personality axis in this species, showed heritability estimates at the upper end of the range previously described for social behaviours, with important variation across sexes. The results from both Pool-seq and RNA-seq data indicated that genes involved in neuron migration and synaptic function were instrumental in the evolution of sociability, highlighting a crucial role of glutamatergic synaptic function and calcium-dependent signalling processes in the evolution of schooling.

  • 31. Currie, Thomas E.
    et al.
    Mulder, Monique Borgerhoff
    Fogarty, Laurel
    Schlüter, Maja
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Folke, Carl
    Haider, L. Jamila
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Caniglia, Guido
    Tavoni, Alessandro
    Jansen, Raf E. V.
    Søgaard Jørgensen, Peter
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Royal Swedish Academy of Sciences, Sweden.
    Waring, Timothy M.
    Integrating evolutionary theory and social–ecological systems research to address the sustainability challenges of the Anthropocene2024In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, E-ISSN 1471-2970, Vol. 379, no 1893, article id 20220262Article, review/survey (Refereed)
    Abstract [en]

    The rapid, human-induced changes in the Earth system during the Anthropocene present humanity with critical sustainability challenges. Social–ecological systems (SES) research provides multiple approaches for understanding the complex interactions between humans, social systems, and environments and how we might direct them towards healthier and more resilient futures. However, general theories of SES change have yet to be fully developed. Formal evolutionary theory has been applied as a dynamic theory of change of complex phenomena in biology and the social sciences, but rarely in SES research. In this paper, we explore the connections between both fields, hoping to foster collaboration. After sketching out the distinct intellectual traditions of SES research and evolutionary theory, we map some of their terminological and theoretical connections. We then provide examples of how evolutionary theory might be incorporated into SES research through the use of systems mapping to identify evolutionary processes in SES, the application of concepts from evolutionary developmental biology to understand the connections between systems changes and evolutionary changes, and how evolutionary thinking may help design interventions for beneficial change. Integrating evolutionary theory and SES research can lead to a better understanding of SES changes and positive interventions for a more sustainable Anthropocene.

  • 32. Dalin, Peter
    et al.
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Host-plant quality adaptively affects the diapause threshold: evidence from leaf beetles in willow plantations2012In: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 37, no 6, p. 490-499Article in journal (Refereed)
    Abstract [en]

    1. Voltinism of herbivorous insects can vary depending on environmental conditions. The leaf beetle Phratora vulgatissima L. is univoltine in Sweden but will sometimes initiate a second generation in short-rotation coppice (SRC) willow plantations. 2. The study investigated whether increased voltinism by P. vulgatissima in plantations can be explained by (i) rapid life-cycle development allowing two generations, or (ii) postponed diapause induction on coppiced willows. 3. In the field, no difference was found in the phenology or development of first-generation broods between plantations (S. viminalis) and natural willow habitats (S. cinerea). However, the induction of diapause occurred 12 weeks later in SRC willow plantations. 4. Laboratory experiments indicated no genetic difference in the critical day-length for diapause induction between beetles originating from plantations and natural habitats. Development time was unaffected by host-plant quality but critical day-length was prolonged by almost an hour when the beetles were reared on a non-preferred willow species (S. phylicifolia). When reared on new leaves from re-sprouting shoots of recently coppiced willow plants, diapause incidence was significantly less than when the beetles were reared on mature leaves from uncoppiced plants. 5. The study suggests that P. vulgatissima has a plastic diapause threshold influenced by host-plant quality. The use of host-plant quality as a diapause-inducing stimulus is likely to be adaptive in cases where food resources are unpredictable, such as when new host-plant tissue is produced after a disturbance. SRC willows may allow two beetle generations due to longer growing seasons of coppiced plants that grow vigorously.

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  • 33.
    Dalsätt, Johan
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Fossil birds: Contributions to the understanding of avian evolution2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The study of the evolution of birds began about 150 years ago with the finding of Archaeopteryx. Yet, many unsolved questions about avian evolution remain to be answered. This thesis aims at addressing some of these questions.

    The Early Cretaceous Confusiusornis is the most well-represented Mesozoic bird in the fossil record. The abundance of fossils facilitates a study of the preservation of specimens in the two geological formations in which this taxon is found. It was demonstrated that specimens in the Yixiang Formation always are represented by complete, articulated skeletons, while those in the Jiofutang Formation often lack the pectoral girdle and the wings.

    Despite the many specimens available of Confusiusornis few clues to the diet of this taxon have been found. We describe a Confusiusornis specimen with a pellet of fish remains preserved in the throat region.

    The enantiornithid birds probably constituted the most species-rich and diverse bird group during the Cretaceous. Several well-preserved specimens have been found in China, e.g. Grabauornis lingyuanensis described herein.

    The mass extinction at the end of the Cretaceous probably gave the only surviving group of birds,Neornithes,chance to radiate and evolve into new niches. One such group is the Strigiformes (owls). We describe a new species from the Eocene Green River Formation in USAthat we suggest is closely related to the contemporary European Prosybris antique and P. medius.

    Although birds are known from several Miocene localities in Europe, the discovery of vertebrate fossils in the Hambach opencast lignite mine was thus unexpected and remarkable. The most significant bird found in Hambach is a specimen of darter, genus Anhinga. It agrees in size, proportions and morphology the fossil species Anhinga pannonica to which we refer the Hambach specimen. Fossils of ducks and galliforms have also been found in deposits at Hambach dated to the Pliocene.

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  • 34.
    Dalsätt, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences. Swedish Museum of National History, Sweden.
    Ericson, Per G. P.
    Zhou, Zhonge
    A New Enantiornithes (Aves) from the Early Cretaceous of China2014In: Acta Geologica Sinica, ISSN 1000-9515, E-ISSN 1755-6724, Vol. 88, no 4, p. 1034-1040Article in journal (Refereed)
    Abstract [en]

    A new bird from the early Cretaceous Yixian Formation of Liaoning, China is described. This new species, Grabauornis lingyuanensis, shares several synapomorphies with the Enantiornithes. The specimen is relatively well preserved. The skeletal morphology of Grabauornis bears close resemblance to that of other Chinese members of this clade. The brachial index (the ratio between the lengths of humerus and ulna) is 0.95, which is close to the average for enantiornithine birds. It indicates that Grabauornis was a rather good flyer, and the presence of an alula in the wing further testifies to this.

  • 35.
    Dalsätt, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Ericson, Per P. G.
    A new species of owl (Aves: Strigiformes) from the Eocene Wasatch Formation, WyomingArticle in journal (Other academic)
  • 36.
    Dalsätt, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Ericson, Per
    Zhou, Z.
    Differential preservation of Confuciusornis specimens in the Yixian and Jiufotang formationsArticle in journal (Other academic)
  • 37.
    Dalsätt, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Mörs, Thomas
    Ericson, Per G. P.
    Fossil birds from the Miocene and Pliocene of Hambach (NW Germany)2006In: Palaeontographica. Abteilung A, Palaozoologie, Stratigraphie, ISSN 0375-0442, Vol. 277, no 1-6, p. 113-121Article in journal (Refereed)
  • 38.
    Dalsätt, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Zhou, Z.
    Zhang, F.
    Ericson, Per G. P.
    Food remains in Confuciusornis sanctus suggest a fish diet2006In: Die Naturwissenschaften, ISSN 0028-1042, E-ISSN 1432-1904, Vol. 93, no 9, p. 444-446Article in journal (Refereed)
    Abstract [en]

    Despite hundreds of excellent fossils of Confuciusornis, the most abundant group of birds in the Early Cretaceous, ‘Jehol Biota’ in China, there is yet no indication of the food choice of these birds. Here, we describe fish remains preserved in the alimentary system of a specimen of Confuciusornis sanctus from the Jiufotang Formation. This find is about five million years younger than all previously published confuciusornithid birds from the Yixian Formation. Although it is unknown how common fish was in the diet of Confuciusornis, the find does not support previous hypotheses that it fed on plants or grain.

  • 39.
    Dalén, Love
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Centre for Palaeogenetics, Sweden; Swedish Museum of Natural History, Sweden.
    Heintzman, Peter
    Stockholm University, Faculty of Science, Department of Geological Sciences. Centre for Palaeogenetics, Sweden.
    Kapp, Joshua D
    Shapiro, Beth
    Deep-time paleogenomics and the limits of DNA survival2023In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 382, no 6666, p. 48-53Article in journal (Refereed)
    Abstract [en]

    Although most ancient DNA studies have focused on the last 50,000 years, paleogenomic approaches can now reach into the early Pleistocene, an epoch of repeated environmental changes that shaped present-day biodiversity. Emerging deep-time genomic transects, including from DNA preserved in sediments, will enable inference of adaptive evolution, discovery of unrecognized species, and exploration of how glaciations, volcanism, and paleomagnetic reversals shaped demography and community composition. In this Review, we explore the state-of-the-art in paleogenomics and discuss key challenges, including technical limitations, evolutionary divergence and associated biases, and the need for more precise dating of remains and sediments. We conclude that with improvements in laboratory and computational methods, the emerging field of deep-time paleogenomics will expand the range of questions addressable using ancient DNA.

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  • 40.
    de Barra, Mícheál
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. University of London, England.
    DeBruine, Lisa M.
    Jones, Benedict C.
    Mahmud, Zahid Hayat
    Curtis, Valerie A.
    Illness in childhood predicts face preferences in adulthood2013In: Evolution and human behavior, ISSN 1090-5138, E-ISSN 1879-0607, Vol. 34, no 6, p. 384-389Article in journal (Refereed)
    Abstract [en]

    The value of different mate choices may depend on the local pathogen ecology and on personal infection susceptibility: when there is a high risk of infection, choosing a healthy or immunocompetent mate may be particularly important. Frequency of childhood illness may act as a cue of the ecological and immunological factors relevant to mate preferences. Consistent with this proposal, we found that childhood illness - and frequency of diarrhea in particular - was positively correlated with preferences for exaggerated sex-typical characteristics in opposite-sex, but not same-sex, faces. Moreover, this relationship was stronger among individuals with poorer current health. These data suggest that childhood illness may play a role in calibrating adult mate preferences and have implications for theories of disease-avoidance psychology, life-history strategy and cross-cultural differences in mate preferences.

  • 41.
    de la Paz Celorio-Mancera, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Wheat, Christopher W.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Huss, Mikael
    Vezzi, Francesco
    Neethiraj, Ramprasad
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Reimegård, Johan
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Evolutionary history of host use, rather than plant phylogeny, determines gene expression in a generalist butterfly2016In: BMC Evolutionary Biology, E-ISSN 1471-2148, Vol. 16, article id 59Article in journal (Refereed)
    Abstract [en]

    Background: Although most insect species are specialized on one or few groups of plants, there are phytophagous insects that seem to use virtually any kind of plant as food. Understanding the nature of this ability to feed on a wide repertoire of plants is crucial for the control of pest species and for the elucidation of the macroevolutionary mechanisms of speciation and diversification of insect herbivores. Here we studied Vanessa cardui, the species with the widest diet breadth among butterflies and a potential insect pest, by comparing tissue-specific transcriptomes from caterpillars that were reared on different host plants. We tested whether the similarities of gene-expression response reflect the evolutionary history of adaptation to these plants in the Vanessa and related genera, against the null hypothesis of transcriptional profiles reflecting plant phylogenetic relatedness. Result: Using both unsupervised and supervised methods of data analysis, we found that the tissue-specific patterns of caterpillar gene expression are better explained by the evolutionary history of adaptation of the insects to the plants than by plant phylogeny. Conclusion: Our findings suggest that V. cardui may use two sets of expressed genes to achieve polyphagy, one associated with the ancestral capability to consume Rosids and Asterids, and another allowing the caterpillar to incorporate a wide range of novel host-plants.

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  • 42. Dehasque, Marianne
    et al.
    Morales, Hernán E.
    Díez del Molino, David
    Pečnerová, Patrícia
    Chacón-Duque, J. Camilo
    Kanelidou, Foteini
    Muller, Héloïse
    Plotnikov, Valeri
    Protopopov, Albert
    Tikhonov, Alexei
    Nikolskiy, Pavel
    Danilov, Gleb K.
    Heintzman, Peter D.
    Oskolkov, Nikolay
    Gilbert, M. Thomas P.
    Götherström, Anders
    van der Valk, Tom
    Vartanyan, Sergey
    Dalén, Love
    Temporal dynamics of woolly mammoth genome erosion prior to extinctionManuscript (preprint) (Other academic)
    Abstract [en]

    A large number of species have recently recovered from near-extinction events. Understanding the genetic consequences of severe population declines followed by demographic recoveries is key to predict the long-term viability of species in order to mitigate future extinction risks. Although these species have avoided the immediate extinction threat, their long-term viability remains questionable due to the genetic consequences of population declines, which are not understood on a time scale beyond a few generations. The woolly mammoth (Mammuthus primigenius) population on Wrangel Island is an excellent model system to investigate long-term genetic consequences of a population bottleneck. Mammoths became isolated on the island in the early Holocene due to rising sea levels, and persisted for over 200 generations (~6,000 years) before becoming extinct ~4,000 years ago. To study the evolutionary processes leading up to the extinction of the woolly mammoth on the island, we analysed 21 Siberian woolly mammoth genomes, including that of one of the last known mammoths. Our results show that the Wrangel Island mammoths recovered quickly from an initially severe bottleneck, and subsequently remained demographically stable during the ensuing 6 millennia. Further, we find that highly deleterious mutations were gradually purged from the population, whereas there was an accumulation of mildly deleterious mutations. The gradual purging of highly deleterious mutations suggests an ongoing inbreeding depression that lasted for hundreds of generations. This time-lag between demographic and genetic recovery has wide-ranging implications for conservation management of recently bottlenecked present-day populations.

  • 43. Delling, Bo
    et al.
    Thörn, Filip
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden.
    Norén, Michael
    Irestedt, Martin
    Museomics reveals the phylogenetic position of the extinct Moroccan trout Salmo pallaryi2023In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 102, no 3, p. 619-627Article in journal (Refereed)
    Abstract [en]

    The authors used museomics to reconstruct the mitochondrial genome from two individuals of the Moroccan, endemic and extinct trout, Salmo pallaryi. They further obtained partial data from 21 nuclear genes previously used for trout phylogenetic analyses. Phylogenetic analyses, including publicly available data from the mitochondrial control region and the cytochrome b gene, and the 21 nuclear genes, place S. pallaryi among other North African trouts. mtDNA places S. pallaryi close to Salmo macrostigma within a single North African clade. Although the nuclear coverage of the genome was low, both specimens were independently positioned as sisters to one of two distantly related North African clades, viz. the Atlas clade with the Dades trout, Salmo multipunctatus. Phylogenetic discordance between mtDNA and nuclear DNA phylogenies is briefly discussed. As several specimens that were extracted failed to produce DNA of sufficient quality, the authors discuss potential reasons for the failure. They suggest that museum specimens in poor physical condition may be better for DNA extraction compared to better-preserved ones, possibly related to the innovation of formalin as a fixative before ethanol storage in the early 20th century.

  • 44.
    Devigili, Alessandro
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Fernlund Isaksson, Erika
    Stockholm University, Faculty of Science, Department of Zoology.
    Puniamoorthy, Nalini
    Fitzpatrick, John L.
    Stockholm University, Faculty of Science, Department of Zoology.
    Behavioral Variation in the Pygmy Halfbeak Dermogenys collettei: Comparing Shoals With Contrasting Ecologies2021In: Frontiers in Ecology and Evolution, E-ISSN 2296-701X, Vol. 9, article id 607600Article in journal (Refereed)
    Abstract [en]

    Variation in biotic and abiotic factors among populations affects individual behaviors by transforming the social landscape and shaping mating systems. Consequently, describing behaviors in natural populations requires consideration of the biological and physical factors that different individuals face. Here, we examined variation in socio-sexual and locomotor behaviors in a small, livebearing, freshwater fish, the pygmy halfbeak Dermogenys collettei, across natural populations in Singapore. The pygmy halfbeak is a surface feeding fish that spends most of the time near the water surface, making it ideal for non-invasive behavioral observations. We compared behaviors between sexes among 26 shoals while simultaneously accounting for environmental variation. We demonstrated that sexual interactions and locomotor behaviors differed among shoals with varying levels of canopy cover and water flow. Specifically, in areas with greater canopy cover, sexual interactions decreased, whereas time spent in a stationary position increased. Sexual interactions were more numerous in still water, where fish spent less time swimming. Variation in the expression of socio-sexual and locomotor behaviors were not associated with differences in the amount of aquatic vegetation, water depth or halfbeak shoal size. Agonistic interactions were robust to environmental effects, showing little variation among environments. However, there were strong sex effects, with males performing more agonistic behaviors and spending less time in a stationary position compared to females, regardless of the environment. Moreover, sexual interactions, measured as actively performed by males and passively received by females, were on average more frequent in males than in females. Our findings help us explore the proximal causes of intraspecific behavioral variation and suggest that fundamental information on socio-sexual behaviors from wild populations can lead to a better understanding of how sexual selection operates when the strength of natural selection varies across environments.

  • 45.
    Dinca, Vlad
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Consejo Superior de Investigaciones Cientificas (CSIC) Pompeu Fabra University.
    Runquist, Marten
    Nilsson, Marten
    Vila, Roger
    Dispersal, fragmentation, and isolation shape the phylogeography of the European lineages of Polyommatus (Agrodiaetus) ripartii (Lepidoptera: Lycaenidae):  2013In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 109, no 4, p. 817-829Article in journal (Refereed)
    Abstract [en]

    Polyommatus ripartii is a biogeographically and taxonomically poorly understood species of butterfly with a scattered distribution in Europe. Recently, it has been shown that this species includes several European endemic and localized taxa (galloi, exuberans, agenjoi) that were previously considered species and even protected, a result that poses further questions about the processes that led to its current distribution. We analysed mitochondrial DNA and the morphology of P.ripartii specimens to study the phylogeography of European populations. Three genetically differentiated but apparently synmorphic lineages occur in Europe that could be considered evolutionarily significant units for conservation. Their strongly fragmented and counterintuitive distribution seems to be the result of multiple range expansions and contractions along Pleistocene climatic oscillations. Remarkably, based on the 79 specimens studied, these genetic lineages do not seem to extensively coexist in the distributional mosaic, a phenomenon most evident in the Iberian Peninsula. One of the important gaps in the European distribution of P.ripartii is reduced by the discovery of new Croatian populations, which also facilitate a better understanding of the biogeography of the species.

  • 46.
    Dort, Hanna Nicole
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Okamura, Yu
    Department of Biological Sciences, The University of Tokyo.
    Wahlberg, Niklas
    Department of Biology, Lund University.
    Vogel, Heiko
    Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology.
    Wheat, Christopher
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    The Great Pieridae Project: Associating gene-birth death dynamics with dietary shifts in crucifer-feeding butterflies and their relatives.Manuscript (preprint) (Other academic)
  • 47.
    Dort, Hanna Nicole
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    van der Bijl, Wouter
    Wahlberg, Niklas
    Department of Biology, Lund University.
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Wheat, Christopher
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Genome-wide gene birth-death dynamics are associated with diet breadth variation in LepidopteraManuscript (preprint) (Other academic)
  • 48.
    Dort, Hanna Nicole
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Wheat, Christopher
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Steward, Rachel A.
    Department of Biology, Lund University.
    Removing specialized detoxification mechanisms reveals generalized responses in a host plant feeding specialist.Manuscript (preprint) (Other academic)
    Abstract [en]

    Coevolutionary innovations are thought to be a large driver of insect and plant biodiversity. Several such innovations have arisen from gene duplication events and subsequent divergence between gene copies, including many adaptations that allow insects to overcome defensive host plant chemistry. However, the role adaptive gene duplicates play in a wider transcriptional framework is still poorly understood. Here, we use short-term feeding assays and CRISPR-Cas9 modified lines of cabbage white (Pieris brassicae) caterpillars to explore how non-functionalization of different members of a family of specialized detoxification genes affects the larval transcriptome at large. We find that the transcriptional response to host plant changes is strongest when all genes in the detoxification family are functional, suggesting that the gene family is part of a larger regulatory response to host plant defences. Further, among individuals lacking specialized detoxification genes, we find that certain general detoxification genes are uniquely upregulated in response to stressful host plant switches. Our results shed light on the importance of transcriptional plasticity in plant-insect interactions and lead to new hypotheses about the initial colonization of mustards by early pierid butterflies.

  • 49. Dussex, Nicolas
    et al.
    Tørresen, Ole K.
    van der Valk, Tom
    Le Moullec, Mathilde
    Veiberg, Vebjørn
    Tooming-Klunderud, Ave
    Skage, Morten
    Garmann-Aarhus, Benedicte
    Wood, Jonathan
    Rasmussen, Jacob A.
    Pedersen, Åshild Ø.
    Martin, Sarah L. F.
    Røed, Knut H.
    Jakobsen, Kjetill S.
    Dalén, Love
    Stockholm University, Faculty of Science, Department of Zoology. Centre for PalaeoGenetics, Sweden; Swedish Museum of Natural History, Sweden.
    Hansen, Brage B.
    Martin, Michael D.
    Adaptation to the High-Arctic island environment despite long-term reduced genetic variation in Svalbard reindeer2023In: iScience, E-ISSN 2589-0042, Vol. 26, no 10, article id 107811Article in journal (Refereed)
    Abstract [en]

    Typically much smaller in number than their mainland counterparts, island populations are ideal systems to investigate genetic threats to small populations. The Svalbard reindeer (Rangifer tarandus platyrhynchus) is an endemic subspecies that colonized the Svalbard archipelago ca. 6,000–8,000 years ago and now shows numerous physiological and morphological adaptations to its arctic habitat. Here, we report a de-novo chromosome-level assembly for Svalbard reindeer and analyze 133 reindeer genomes spanning Svalbard and most of the species’ Holarctic range, to examine the genomic consequences of long-term isolation and small population size in this insular subspecies. Empirical data, demographic reconstructions, and forward simulations show that long-term isolation and high inbreeding levels may have facilitated the reduction of highly deleterious—and to a lesser extent, moderately deleterious—variation. Our study indicates that long-term reduced genetic diversity did not preclude local adaptation to the High Arctic, suggesting that even severely bottlenecked populations can retain evolutionary potential.

  • 50. Dutoit, Ludovic
    et al.
    Mitchell, Kieren J.
    Dussex, Nicolas
    Stockholm University, Faculty of Science, Department of Zoology. Centre for Palaeogenetics, Sweden; Swedish Museum of Natural History, Sweden.
    Kemper, Catherine M.
    Larsson, Petter
    Dalén, Love
    Rawlence, Nicolas J.
    Marx, Felix G.
    Convergent evolution of skim feeding in baleen whales2023In: Marine mammal science, ISSN 0824-0469, E-ISSN 1748-7692, Vol. 39, no 4, p. 1337-1343Article in journal (Refereed)
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