Coevolutionary Process Research Articles

Parallel HIV-1 fitness landscapes shape viral dynamics in humans and macaques that develop broadly neutralizing antibodies.

Human immunodeficiency virus (HIV)-1 exhibits remarkable genetic diversity. For this reason, an effective HIV-1 vaccine must elicit antibodies that can neutralize many variants of the virus. While broadly neutralizing antibodies (bnAbs) have been isolated from HIV-1 infected individuals, a general understanding of the virus-antibody coevolutionary processes that lead to their development remains incomplete. We performed a quantitative study of HIV-1 evolution in two individuals who developed bnAbs. We observed strong selection early in infection for mutations affecting HIV-1 envelope glycosylation and escape from autologous strain-specific antibodies, followed by weaker selection for bnAb resistance later in infection. To confirm our findings, we analyzed data from rhesus macaques infected with viruses derived from the same two individuals. We inferred remarkably similar fitness effects of HIV-1 mutations in humans and macaques. Moreover, we observed a striking pattern of rapid HIV-1 evolution, consistent in both humans and macaques, that precedes the development of bnAbs. Our work highlights strong parallels between infection in rhesus macaques and humans, and it reveals a quantitative evolutionary signature of bnAb development.

Exploring the Multifaceted Role of Viruses in Sustaining Biodiversity: Mechanisms, Implications, and Contributions to Ecosystems Stability

Viruses, traditionally recognized as pathogenic agents, are increasingly acknowledged for their indispensable roles in sustaining biodiversity and fostering ecosystem stability. This review examines the multifaceted contributions of viruses, exploring their influence on nutrient cycling, genetic diversification, and regulation of microbial populations. By mediating microbial interactions, facilitating horizontal gene transfer, and driving co-evolutionary processes, viruses shape the intricate tapestry of life across diverse ecosystems. The primary aim of this study is to synthesize contemporary findings in virology to highlight the universal ecological importance of viruses. Drawing upon research conducted in marine, terrestrial, and extreme habitats, the review delineates the mechanisms through which viruses mediate ecological balance. Utilizing meta-analyses of global virome datasets, coupled with advanced metagenomics and bioinformatics methodologies, this investigation unveils the nuanced interplay between viral activity and ecosystem functionality. The results illuminate the significant role of viruses in regulating population dynamics, promoting evolutionary innovation, and maintaining genetic reservoirs critical for ecological resilience. This research enriches our understanding of viral influence on biogeochemical cycles and biodiversity, establishing viruses as integral components of global ecosystems. Furthermore, it contributes a paradigm shift in virology, advocating for a broader perspective that transcends the traditional view of viruses as mere pathogens. The practical implications are profound, providing insights for conservation biology and climate resilience strategies. By reimagining viruses as keystones of ecological health, this work underscores the necessity of integrating viral ecology into holistic environmental and evolutionary research frameworks, advancing scientific and practical knowledge of ecosystem sustainability.

Coevolution of Giant Molecular Clouds, Filaments, and Clumps as a Function of the Dense Gas Mass Fraction

We investigate the evolutionary dynamics with archival continuum and line data of 27 giant molecular clouds (GMCs) in the Milky Way, focusing on their influence on star formation. Examining the dense gas mass fraction (DGMF) among the GMCs, we categorize them into low-DGMF (DGMF < 20%), medium-DGMF (20% < DGMF < 60%), and high-DGMF (60% < DGMF) groups. The analysis uncovers systematic trends in the free-fall time, virial parameter, surface density, star formation rate (SFR), SFR per unit area (ΣSFR), and star formation efficiency for dense gas as the DGMF increases within GMCs. We identified 362 filaments and 3623 clumps within the GMCs. Increasing DGMF correlates with higher proportions of star-forming clumps and clumps capable of forming massive stars. Clump properties such as hydrogen number density and surface density increase with DGMF, while the mass and radius decrease. The dust temperature and virial parameters show no significant variation with DGMF. We also observe convergence in the hydrogen number density and dust temperature between star-forming and starless clumps with rising DGMF. Filaments are found to be spatially associated with clumps capable of forming high-mass stars, with those on filaments exhibiting greater mass, radius, hydrogen number density, surface density, and velocity dispersion. Moreover, filaments hosting clumps capable of forming high-mass stars demonstrate larger mass, length, and line mass. In summary, this comprehensive analysis of GMCs, filaments, and clumps supports the notion of a multiscale coevolution process. From GMCs to filaments and subsequently to clumps, the DGMF emerges as a valuable tracer for understanding the evolutionary trajectory of GMCs and the processes governing their development.

Genetic elements of a long-standing family business: An analysis of five century-old family businesses based on grounded theory

Succession is a major threat to the sustainable growth of family businesses. This study proposes that the growth of a family business is a co-evolutionary process involving multiple memes, and a family business undergoes succession through memes. To address this exploratory question, the author analyzes entrepreneurial behavior in five well-known century-old Western family enterprises based on grounded theory, and constructs a deoxyribonucleic acid model of the family business. The model not only reveals the most prominent memes in the complex meme system of a family business, but also illustrates the connectivity of different strengths among the organizational memes. The implications and recommendations derived from this study indicate that family businesses should develop specialization and succession capabilities through memes, and explore different means of innovation and adaptation to realize cross-generational growth.

Biogeography confounds the signal of cospeciation in Batesian mimicry

Since the inception of the field of evolution, mimicry has yielded insights into foundational evolutionary processes, including adaptive peak shifts, speciation, and the emergence and maintenance of phenotypic polymorphisms.1,2,3 In recent years, the coevolutionary processes generating mimicry have gained increasing attention from researchers. Despite significant advances in understanding Batesian and Müllerian mimicry in Lepidopteran systems, few other mimetic systems have received similar detailed research. Here, we present a Batesian mimicry complex involving flightless, armored Pachyrhynchus weevils and their winged Doliops longhorn beetle mimics and examine their coevolutionary patterns within the Philippine archipelagos. Pachyrhynchus weevils are primarily found in the Philippines, where distinct species radiations have occurred on different islands, each with unique color patterns serving as a warning to predators. This defensive trait and mimicry between unrelated species were first described by Wallace in 1889. Notably, the distantly related longhorn beetle Doliops, despite being soft-bodied and ostensibly palatable, mimics the heavily armored, flightless Pachyrhynchus. To address mimicry in this system, we reconstructed the phylogeny of Doliops using a probe set consisting of 38,000 ultraconserved elements. Our study examines the following questions central to understanding the Pachyrhynchus-Doliops mimicry system: (1) to what extent are coevolutionary interactions conserved (i.e., lineage-constrained) and (2) are the codiversification patterns primarily driven by biotic or abiotic factors?4,5,6 To assess color mimicry and cospeciation, we examined the evolution of nanostructure-based warning colors and the effect of island biogeography on cospeciation. Our findings demonstrate the beetle's ability to repeatedly evolve multiple solutions to similar evolutionary challenges, evolving similar color patterns using different types of photonic crystals with varying degrees of order. We revealed that the observed pattern of cospeciation is driven mainly by abiotic factors from their biogeographic history. Unlike the patterns of coevolution seen between angiosperms and insect lineages,7 most ecological interactions do not persist longer than a few million years, leading to patterns of modularity rather than ecological nestedness.4,6,7.

Business services in regional economies: exploring the co-evolution of supply, demand, and sectoral interactions

The aim of this paper is to demonstrate how economic growth stimulates business-service providers to develop new service varieties, which, in turn, enhance the productivity of business-service buyers. This creates a coevolutionary process where service suppliers and customers interact, leading to an increase in the number of differentiated service offerings. We introduce a framework for local economies, wherein business-service sectors evolve in response to local demand potential, while non-business-service sectors grow based on each economy’s supply potential. Business service growth is more rapid in local economies with higher demand potential, while non-business-service sectors expand faster in areas where the business-service supply potential is greater. A key assumption is that business service firms operate in a monopolistic competition environment, where an increase in business-service capacity leads to an expansion in the variety of services offered. This, in turn, enhances the diversity of service offerings in municipalities with strong demand potential. Additionally, service providers not only deliver innovation-related information to client firms but also unintentionally disseminate knowledge within the region, fostering knowledge spillovers among firms.

Co-evolution of M23C6 precipitates and cavities in a boron-free Ni-based alloy GH3617 under high-temperature He ion irradiation: Effects on cavity swelling and mechanical properties

Ni-based alloys are promising materials for advanced nuclear reactors operating at high temperatures due to their exceptional resistance to high temperatures and corrosion. Understanding the synergy of phase stability and helium effects is crucial for assessing the long-term performance and reliability of these alloys in advanced nuclear reactors. This study has investigated the co-evolution behavior of M23C6 precipitates and cavities in a boron-free solid solution strengthened Ni-based alloy GH3617 under high-temperature He ion irradiation, and its impact on alloy swelling and mechanical properties, by He ion irradiation experiments with the highest fluence of 1 × 1017 He/cm2 up to 800 °C. Transmission Electron Microscopy (TEM) and Nanoindentation are employed to investigate microstructural evolution and mechanical properties, respectively. The findings show that at room temperature and 500 °C, cavities and dislocation loops were the dominant irradiation defects, whereas at 800 °C, the density of cavities and dislocations reduced while the formation of M23C6 precipitates increased. These precipitates act as effective trapping sites for He and point defect, leading to cavity formation at the interfaces or within the precipitates. Moreover, increased irradiation fluence accelerates the co-evolution process, resulting in an increase in the density and size of both precipitates and cavities, ultimately leading to enhanced swelling. The {111} planes are favored interfaces between intragranular M23C6 precipitates and the matrix due to their minimal misfit, while the preferred interface planes between cavities with octahedral or cubo-octahedral shapes and the precipitate/matrix are also {111}, owing to their lower surface energy as well. The co-evolution of cavities and precipitates was found to influence mechanical properties, resulting in an irradiation hardening effect at lower fluences, while softening at higher fluences. This study provides novel insights into the degradation mechanisms of Ni-based alloys under coupling effect of He and high-temperature irradiation.

Coevolutionary dynamics in tropical peat ecosystems: A case study of Sumatra peatlands biosphere reserve

Tropical peat swamp is an essential ecosystem experiencing increased degradation over the past few decades. Therefore, this study used the social-ecological system (SES) perspective to explain the complex relationship between humans and nature in the Sumatran Peatlands Biosphere Reserve. The peat swamp forest has experienced a significant decline, followed by a significant increase in oil palm and forest plantations in areas designated for peat protection. Human systems have evolved to become complex and hierarchical, constituting individuals, groups, organizations, and institutions. Studies on SES conducted in the tropical peatlands of Asia have yet to address the co-evolutionary processes occurring in this region, which could illustrate the dynamic relationship between humans and nature. This study highlights the co-evolutionary processes occurring in the tropical peatland biosphere reserve and provides insights into their sustainability trajectory. Moreover, the coevolution process shows that biosphere reserve is shifting toward an unsustainable path. This is indicated by ongoing degradation in three zones and a lack of a comprehensive framework for landscape-scale water management. Implementing landscape-scale water management is essential to sustain the capacity of peatlands social-ecological systems facing disturbances, and it is important to maintain biodiversity. In addition, exploring alternative development pathways can help alter these trajectories toward sustainability.

The coevolution of technology, markets, and culture: the challenging case of AI

Artificial intelligence (AI) is at the center of economic, social, political, and ethical debate. For the first time in human history, since the appearance of writing, a new type of “intelligence” is impacting the very nature of social relationships. New technologies are not only changing the operating model of markets and value chains in an accelerated way but also in how information is generated and processed, how labor, social relations, and culture evolve, etc. In this paper, we pursue two main goals. First, to set up an analytical framework in which cognitive, technical, and cultural dynamics are intertwined with the processes of deployment of economic action. Secondly, we utilize this framework to explore some key features and challenges of AI and its impact on coevolutionary processes at the cognitive, market, and cultural levels. We devote special attention to the consequences that AI may have for the concept of (economic) rationality and the formation of action plans. We conclude that AI will massively enhance agents’ spaces of action by improving efficiency and exploring new possibilities. However, AI will not change the nature of human action and the structure of the evolution of the economic system.

POPULATION DYNAMICS OF ENTERIC PARASITES IN THE ENDANGERED VANCOUVER ISLAND MARMOT (MARMOTA VANCOUVERENSIS).

Enteric parasites can have wide-ranging effects throughout an ecosystem, often driving coevolutionary and ecological processes. Parasites have long been overlooked in conservation efforts because of the negative impact inflicted on their hosts; however, parasites make up a significant component of Earth's biodiversity and host conservation efforts need to be parasite inclusive. The Vancouver Island marmot (VIM), Marmota vancouverensis, is an endangered alpine rodent endemic to Vancouver Island, British Columbia, Canada. Captive-bred VIMs are released to augment the wild population, but their susceptibility to parasites is unknown. The objectives of this study were to describe the diversity, prevalence, severity, and temporal variation of VIM enteric parasites. Noninvasive fecal samples were collected from wild and captive marmots and analyzed using a modified McMaster fecal egg floatation technique to indicate parasite prevalence and relative mean abundance. We identified oocysts and ova from 3 parasite taxa including a protozoan coccidium not previously described in the VIM (prevalence 68%), an ascarid nematode Baylisascaris laevis (prevalence 82%), and an anoplocephalid cestode Diandrya vancouverensis (prevalence 8%). Depending on the species, comparisons revealed variation in parasite infection by sex, by colony, and between wild and captive VIMs, but not among age classes or by female reproductive status. Finally, captive VIMs displayed significant monthly variation in parasite prevalence and mean egg abundance, suggesting a seasonal influence on parasite egg shedding. This information is critically important for future research investigating the influences of these trends on the health, ecology, and conservation of VIMs and their parasites.

The co-evolution of sustainable finance stakeholders under the EU taxonomy for sustainable activities: an exploratory study of Irish disclosure experiences

PurposeIn pursuit of objectives, under the European Green Deal, to channel capital flows to sustainable activities, the EU Taxonomy offers clarity, labelling real economic activities as “sustainable”, based on technical screening criteria. This study of disclosure experiences aims to explore the role of co-evolutionary relationships in the Taxonomy’s effectiveness.Design/methodology/approachCo-evolution theory implies a dynamic interplay among sustainable finance stakeholders (SFSs), through adjustment to, impact on and operationalisation of the Taxonomy. Corporate disclosure experiences, including those of financial institutions and related SFS experiences, may reveal co-evolutionary processes. With significant Undertakings for Collective Investment in Transferable Securities (UCITS) and Alternative Investment Funds (AIFs), Irish SFSs provide contextual insight. Semi-structured interviews with a purposive sample of Irish SFSs capture inaugural corporate Taxonomy disclosure experiences.FindingsA thematic analysis reveals six co-evolutionary processes that facilitate Taxonomy implementation in pursuit of policy objectives: [1] cross-functional reporting; [2] iterative pre-empting and addressing compliance issues; [3] regulation as a catalyst for co-evolution; [4] advanced capacity building; [5] stakeholder adaptation and [6] graduated use of ESG data. Implications for sustainability policy development and management are significant.Practical implicationsWhilst limited to just one EU jurisdiction, given limited prior empirical evidence for sustainable finance regulations from co-evolutionary perspectives, this study highlights a catalytic, yet precautionary role for co-evolution in their transformation effectiveness. As such, they must take account of their potential to stimulate co-evolution and to nurture it in pursuit of their policy objectives.Social implicationsThe findings of this study add to a small, but growing body of academic literature on the Taxonomy Regulation, which suggests that a co-evolutionary lens is important for gaining a comprehensive understanding of its early-stage dynamics. From an implementation perspective, the qualitative data reveals actionable implications for regulators and policymakers, such as building capacity, better anticipation of outcomes and investment in data infrastructure.Originality/valueUnlike existing analyses of disclosures, this study offers a co-evolutionary lens on Taxonomy contributions to sustainable development through qualitative accounts.

Evaluating Stakeholders’ Decisions in A Blockchain-Based Recycling Construction Waste Project: A Hybrid Evolutionary Game and System Dynamics Approach

To promote efficient construction waste recycling and reuse, a novel waste management approach based on blockchain technology was introduced to the industry. However, adopting blockchain platforms in construction waste recycling and reuse may impact the behavioral strategies of stakeholders and impede the prediction of the specific impacts of stakeholders’ decisions. Accordingly, this study addresses two primary questions: (1) What are the collaborative framework and the behavioral evolution trends of multiple stakeholders within the context of blockchain? (2) How can the behavioral strategies of multiple stakeholders be systematically coordinated to achieve efficient construction waste recycling and reuse driven by blockchain? To answer these questions, a tripartite game model combined with system dynamics was constructed. In this model, we aimed to elucidate the internal organizational framework, analyze the dynamic evolution process, and assess the influence of decisions made by multiple stakeholders at the individual level. It also offers corresponding policy recommendations for efficient construction waste recycling and reuse driven by blockchain at the system level. This study offers three innovations. First, it considers the decision-making of multiple stakeholders as an interdependent and coevolutionary process to overcome the defects of analyzing only one type of participant. Second, in contrast to the static analysis method, it employs a dynamic system approach to deeply analyze the evolving structures of blockchain-based projects. Third, it provides a theoretical framework for the practical implementation of blockchain-driven platforms in managing construction waste recycling and reuse, thus fostering effective policy development and management practices. This framework aims to promote sustainable development in construction waste recycling and reuse projects in China as well as globally.

The ontology of coevolution beyond economic systems

This paper provides an analysis of the general ontology of coevolutionary processes. I argue that to properly understand the ontological phenomenon of coevolution, we need to move away from neophobic, flat, and substance-based ontologies and adopt a pluralist and emergentist process metaphysics that takes into account both horizontal and vertical codetermination. Following this approach, I differentiate between ontological (co)evolution in a general and specific sense. General (co)evolution can be observed in physical and chemical matter. Before the emergence of living matter, the universe evolved, achieving more ontological complexity and qualitative density. Since physical and chemical matter are made up of a complex interplay of continuities and discontinuities, physical and chemical entities and processes are multiple and codetermine each other through a dynamic complex patterning, as basically described by what the Spanish philosopher Gustavo Bueno called symploké following Plato’s Sophist. Therefore, physical and chemical evolutionary processes are more accurately described as coevolutionary processes. On the other hand, specific coevolution can be observed in the biological, social, and cultural/artificial realms. Its ontological specificity lies in the dynamic interactions of novelty, replication, and selection, which are absent in physical and chemical matter. In conclusion, I argue that rather than unnecessarily complicating our view of reality, this approach is manageable epistemologically and allows for a better understanding of dynamic codetermination in the universe, from physical matter to cultural spheres.

Population genomics of Central Asian peoples unveil ancient Trans-Eurasian genetic admixture and cultural exchanges

Central Asia, a crucible of prehistoric and historical Trans-Eurasian interactions, has been pivotal in shaping cultural exchanges, population dynamics, and genetic admixture. Recent insights from ancient DNA studies have shed light on the extensive population turnover within this region, encompassing a spectrum of groups from Paleolithic hunter-gatherers to Holocene herders and the nomadic pastoralist empires of historical times. The genomic analysis of ancient pathogens across the Eurasian steppe has further deepened our understanding of pathogen origins, clonal expansions, and the intricate processes of host-pathogen coevolution in relation to varying pathogen exposures and their spread. We consolidate the latest findings pertaining to the ancient human and pathogen genomes of Central Asia, elucidating their profound influence on the genomic tapestry of contemporary Central Asians. A notable gap in the current genomic databases for Central Asia is underscored, particularly within the scope of genomics-driven precision medicine. We stress the urgent need for the development of extensive, region-specific genomic resources that hold promise for revealing the genetic blueprints underlying human traits and diseases, refining polygenic scoring models for predictive medicine, and bolstering genomic research endeavors across Central Asia.

Coevolution of relationship networks and resistance behaviors for building information modeling implementation in construction projects

Heterogeneous individual participants are embedded within multiple dynamic intra-project relationship networks, which can both shape and be shaped by individual behaviors through social influence and selection processes, respectively. Yet empirical research on these complex interrelationships within projects remains lacking. This study fills this lacuna by investigating how formal task-oriented communication and informal knowledge-oriented advice networks coevolve with individual resistance behaviors for building information modeling (BIM) implementation in construction projects through social selection and influence processes. Stochastic actor-oriented network models and longitudinal data on project-level BIM implementation practices are used to examine this question. After controlling for related covariate and structural effects, the results provide clear evidence for the social selection process in which communication and advice ties in the networks are both more frequently formed between project participants with more similar resistance behaviors. Concerning the social influence process, the results show that compared with knowledge-oriented advice ties, task-oriented communication ties tend to more significantly influence the assimilation of resistance behaviors. The network-behavior coevolution process is simultaneously associated with the covariate effects related to individual experience as well as the structural effects related to reciprocity and triadic closure. As a pioneering effort of using longitudinal network modeling methods to empirically characterize network-behavior dynamics in projects, this study provides a deepened understanding of how social selection and influence processes collectively shape the dynamic interactions among heterogeneous project participants as a complex adaptive system.

Molecular Mechanisms of Bacterial Resistance to Antimicrobial Peptides in the Modern Era: An Updated Review.

Antimicrobial resistance (AMR) poses a serious global health concern, resulting in a significant number of deaths annually due to infections that are resistant to treatment. Amidst this crisis, antimicrobial peptides (AMPs) have emerged as promising alternatives to conventional antibiotics (ATBs). These cationic peptides, naturally produced by all kingdoms of life, play a crucial role in the innate immune system of multicellular organisms and in bacterial interspecies competition by exhibiting broad-spectrum activity against bacteria, fungi, viruses, and parasites. AMPs target bacterial pathogens through multiple mechanisms, most importantly by disrupting their membranes, leading to cell lysis. However, bacterial resistance to host AMPs has emerged due to a slow co-evolutionary process between microorganisms and their hosts. Alarmingly, the development of resistance to last-resort AMPs in the treatment of MDR infections, such as colistin, is attributed to the misuse of this peptide and the high rate of horizontal genetic transfer of the corresponding resistance genes. AMP-resistant bacteria employ diverse mechanisms, including but not limited to proteolytic degradation, extracellular trapping and inactivation, active efflux, as well as complex modifications in bacterial cell wall and membrane structures. This review comprehensively examines all constitutive and inducible molecular resistance mechanisms to AMPs supported by experimental evidence described to date in bacterial pathogens. We also explore the specificity of these mechanisms toward structurally diverse AMPs to broaden and enhance their potential in developing and applying them as therapeutics for MDR bacteria. Additionally, we provide insights into the significance of AMP resistance within the context of host-pathogen interactions.

Screening of reference genes for gene expression study in different tissues from the transcriptome data of the vector leafhopper Psammotettix striatus

Selecting appropriate reference genes is crucial for ensuring the accuracy and reliability of gene expression study using reverse transcription-quantitative PCR (RT-qPCR). To screen the optimal reference genes for analyzing gene expression in different tissues of the vector leafhopper Psammotettix striatus which causes extensive damage to a wide range of crops by vectoring multiple plant pathogenic microorganisms, the transcriptome data from Malpighian tubules (MTs) of P. striatus were mined. Twenty alternative candidate reference genes were initially selected for screening, among which seven genes with diverse Gene Ontology (GO) annotations were choosed as candidate reference genes, i.e., ribosomal protein L7A (RPL7A), ribosomal protein S28 (RPS28), ribosomal protein L22 (RPL22), ribosomal protein LP2 (RPLP2), H3 histone family 3A (H3F3A), elongation factor 1γ (EF-1γ), and elongation factor 1α (EF-1α). Gene expression levels in different tissues of P. striatus adults were examined using RT-qPCR, and their expression stability was analyzed using multiple reference gene screening software. This study revealed EF-1α as the most abundantly expressed gene, while RPL22 exhibited the lowest expression levels. EF-1α showed the most stable expression, whereas RPS28 showed the least stability. Various software tools confirmed EF-1α as the most stable single reference gene, and EF-1α and RPLP2 an optimal combination. This study provides a foundation for future investigation of the transmission of pathogenic microorganisms mediated by the vector leafhoppers, the function of the MTs, the biosynthesis of brochosomes, the coevolutionary processes and nutritional interactions of symbionts and host insects, and the gene expression study of other sap-sucking insects.

Rapid Evolutionary Characteristics of P1 and T5 Infection in E. coli Strains

The emergence of superbug has once again thrust century-old phage into the spotlight as a hot research topic. While the "phage display" technology has enabled targeted evolution of viruses, the successful application of phage remains uncertain due to their replicative and mutative nature, as well as the complexity of phage-bacteria interactions and evolutionary mechanisms. In this study, we used two rapidly evolving phages, P1 and T5, along with 18 types of E. coli strains, as representatives to explore the evolutionary characteristics of phage-infected bacteria. Our findings confirm that the evolutionary of phages and their hosts is a co-evolutionary process, resembling an "arms race", after the early rapid evolution of P1 and T5, the host range expands to infect different E. coli strains, but continued rapid evolution reaches a certain stage where P1, T5, and E. coli strains all experience a fitness cost, and the host range no longer expands. Three new findings in this study differ from previous studies. Firstly, although E. coli strains were not infected in the same way, there was no statistically significant difference between P1 and T5 infection in different E. coli strains at different evolutionary stages. Secondly, 11 types of E. coli strains that had been infected by T5 during co-evolution all showed E. coli tolerant plaques on the medium at the fifth stage of evolution, whether they had been infected by T5 at that stage of evolution, and at the sixth stage of evolution, all of these tolerant plaques disappeared again. Thirdly, after the fitness cost of the co-evolutionary process had already occurred, although the host range of P1 and T5 no longer continued to expand, the types of E. coli strains infected by P1 and T5 at the same evolutionary stage did not decrease in focus with the continued prolongation of the co-evolutionary time, but instead showed a gradual incremental trend. This study provides experimental evidence for the resolution of phage-bacteria co-evolutionary mechanism and new ideas for phagotherapy strategies for the superbug.

Coevolution-induced selection for and against phenotypic novelty shapes species richness in clade co-diversification.

Coevolution can occur because of species interactions. However, it remains unclear how coevolutionary processes translate into the accumulation of species richness over macroevolutionary timescales. Assuming speciation occurs as a result of genetic differentiation across space due to dispersal limitation, we examine the effects of coevolution-induced phenotypic selection on species diversification. Based on the idea that dispersers often carry novel phenotypes, we propose and test two hypotheses. (1) Stability hypothesis: selection against phenotypic novelty enhances species diversification by strengthening dispersal limitation. (2) Novelty hypothesis: selection for phenotypic novelty impedes species diversification by weakening dispersal limitation. We simulate clade co-diversification using an individual-based model, considering scenarios where phenotypic selection is shaped by neutral dynamics, mutualistic coevolution, or antagonistic coevolution, where coevolution operates through trait matching or trait difference, and where the strength of coevolutionary selection is symmetrical or asymmetrical. Our key assumption that interactions occur between an independent party (whose individuals can establish or persist independently, e.g. hosts) and a dependent party (whose individuals cannot establish or persist independently, e.g. parasites or obligate mutualists) yields two contrasting results. The stability hypothesis is supported in the dependent clade but not in the independent clade. Conversely, the novelty hypothesis is supported in the independent clade but not in the dependent clade. These results are partially corroborated by empirical dispersal data, suggesting that these mechanisms might potentially explain the diversification of some of the most species-rich clades in the Tree of Life.

Parasitoid attachment ability and the host surface wettability

Climbing animals such as geckos and arthropods developed astonishing adhesive mechanisms which are fundamental for their survival and represent valuable models for biomimetic purposes. A firm adhesion to the host surface, in order to successfully lay eggs is necessary for the reproduction of most parasitoid insects. In the present study, we performed a comparative investigation on the attachment ability of four parasitoid species (the egg parasitoid Anastatus bifasciatus (Eupelmidae), the aphid parasitoid Aphidius ervi (Braconidae), the fly pupal ectoparasitoid Muscidifurax raptorellus (Pteromalidae) and the pupal parasitoid of Drosophila Trichopria drosophilae (Diapriidae)) with hosts characterized by a surface having different wettability properties. The friction force measurements were performed on smooth artificial (glass) surfaces showing different contact angles of water. We found that attachment systems of parasitoid insects are tuned to match the wettability of the host surface. Sexual dimorphism in the attachment ability of some tested species has been also observed. The obtained results are probably related to different microstructure and chemical composition of the host surfaces and to different chemical composition of the parasitoid adhesive fluid. The data here presented can be interpreted as an adaptation, especially in the female, to the physicochemical properties of the host surface and contribute to shed light on the coevolutionary processes of parasitoid insects and their hosts.