Ecological Competition Research Articles

The health benefits of the active ingredients and whole food components of natural plants through regulating the flora

With the cooperation of bacteria and the human body, the nutrients in food are deeply digested, utilized, and shared. In addition, symbiosis is formed between microorganisms and hosts. Such a delicate combination makes the microorganisms form the inherent flora in the human body. They obtain the biological basis for survival, and provide the necessary regulation and support for the host in terms of immunity and nutrition, through their functional metabolism and population signals. At present, most of the researches focus on the isolation and evaluation of the functional components of plants, such as plant polysaccharides, polyphenols, flavonoids, and other active functional components. However, in traditional Chinese medicine, plants are often used with whole food components. To date, studies have found that the dynamics of flora affecting human health are not fixed, nor dependent on the change of a single strain. The ecological competition and metabolic regulation between microorganisms are usually coevolved with the host. The regulatory effect of natural plants for both medicine and food mainly depends on their whole food components. This provides evidence to support the role of whole food components played in promoting the efficacy of traditional Chinese medicine from the perspective of microenvironment. Therefore, the development and utilization of medicinal and edible natural plant activities should be fully understood and evaluated with flora regulation.

Mid-Phanerozoic microbialite forms and associated facies in the northern Perth Basin, Western Australia, and their relationship to the end-Permian mass extinction

Throughout geological history, biodiversity trends have been punctuated by sharp declines coinciding with mass extinction events. Certain organisms—known as disaster forms—flourish during the extinction aftermath from a lack of ecological competition and predation. Microbialites (in particular, stromatolites) are known to increase in environmental diversity following these biotic crises. However, it remains important to identify whether individual microbialite occurrences are a result of globally driven competition reduction or favourable local conditions. Here, we reconsider stromatolites from the northern Perth Basin of Western Australia, previously reported as Smithian (late Olenekian) in age and part of a biotic rebound following the end-Permian mass extinction and re-evaluate their paleodepositional setting and age. Detailed mapping, macro-analysis and meso-analysis of the Perth Basin locality have identified a well-preserved and diverse morphological assemblage of stromatolites that are intimately associated with a coarse siliciclastic facies. The characteristics of, and relationships between the stromatolitic and coarse siliciclastic facies support a restricted aquatic paleodepositional environment with fluvial/alluvial influences. In the Perth Basin, such depositional environments occurred most commonly during the Permian (Guadalupian to Lopingian). The robustness of previous age constraints interpreted from overlying strata (Kockatea Shale) are questioned by the identification of a depositional hiatus and onlapping relationship of the Kockatea Shale on the stromatolitic sequence. Therefore, we suggest that the mid-Phanerozoic northern Perth Basin Stromatolitic Sequence cannot be unequivocally associated with the end-Permian mass extinction and may have instead thrived owing to a favourable paleodepositional setting. The mid-Phanerozoic northern Perth Basin stromatolites are not a unique case. A compilation of reported Permian and Triassic microbialite occurrences shows that stromatolites, although most common following the end-Permian mass extinction, also occur before and after the extinction event in a range of environmental settings. KEY POINTS Ten microbialite forms were described and mapped out over 30 km in the northern Perth Basin. Perth Basin Stromatolitic Sequence formed in a restricted aquatic depositional setting with fluvial and/or alluvial influences. Stromatolites from the northern Perth Basin are unlikely to be associated with the end-Permian mass.

Antibiotic tolerance and degradation capacity of the organic pollutant-degrading bacterium Rhodococcus biphenylivorans TG9T

Antibiotics are ubiquitous in soil due to natural ecological competition, as well as emerging contaminants due to anthropogenic inputs. Under environmental factors like antibiotic stress, some bacteria, including those that degrade environmental pollutants, can enter a dormant state as a survival strategy, thereby limiting their metabolic activity and function. Dormancy has a critical influence on the degradative activity of bacteria, dramatically decreasing the rate at which they transform organic pollutants. To better understand this phenomenon in environmental pollutant-degrading bacteria, we investigated dormancy transitions induced with norfloxacin in Rhodococcus biphenylivorans TG9T using next-generation proteomics, proteogenomics, and additional experiments. Our results suggest that exposure to norfloxacin inhibited DNA replication, which led to damage to the cell. Dormant cells then likely triggered DNA repair, particularly homologous recombination, for continued survival. The results also indicated that substrate transport (ATP-binding cassette transporter), ATP production, and the tricarboxylic acid (TCA) cycle were repressed during dormancy, and degradation of organic pollutants was down-regulated. Given the widespread phenomenon of dormancy among bacteria involved in pollutant removal systems, this study improves our understanding of possible implications of antibiotic survival strategies on biotransformation of mixtures containing antibiotics as well as other organics.

Association of bacterial community types, functional microbial processes and lung disease in cystic fibrosis airways.

Bacterial infection and inflammation of the airways are the leading causes of morbidity and mortality in persons with cystic fibrosis (CF). The ecology of the bacterial communities inhabiting CF airways is poorly understood, especially with respect to how community structure, dynamics, and microbial metabolic activity relate to clinical outcomes. In this study, the bacterial communities in 818 sputum samples from 109 persons with CF were analyzed by sequencing bacterial 16S rRNA gene amplicons. We identified eight alternative community types (pulmotypes) by using a Dirichlet multinomial mixture model and studied their temporal dynamics in the cohort. Across patients, the pulmotypes displayed chronological patterns in the transition among each other. Furthermore, significant correlations between pulmotypes and patient clinical status were detected by using multinomial mixed effects models, principal components regression, and statistical testing. Constructing pulmotype-specific metabolic activity profiles, we found that pulmotype microbiota drive distinct community functions including mucus degradation or increased acid production. These results indicate that pulmotypes are the result of ordered, underlying drivers such as predominant metabolism, ecological competition, and niche construction and can form the basis for quantitative, predictive models supporting clinical treatment decisions.

Highlighting Theodor W. Engelmann's “Farbe und Assimilation” [Color and Assimilation

AbstractIn 1883, Theodor Wilhelm Engelmann, a German scientist, wrote his essay “color and assimilation” (Ger.: “Farbe und Assimilation”) describing the state of the art in photosynthesis research, his recent findings, and further assumptions based upon his presented results. Nearly 140 years later, many of his assumptions were proven correct. By his still well‐known bacteria experiments using aerotactic, heterotrophic bacteria, he identified the chloroplasts as the location in which photosynthesis and oxygen production takes place. Furthermore, by evaluating the effects of different light spectra, he constructed the first action spectra that demonstrated the implication of the “green gap” of chlorophylls. He further posited that accessory photosynthetic pigments existed to extend the absorption range of chlorophyll. Although infrequently cited, his work was foundational for current ecological research of the vertical appearance of algae species within the underwater gradient in light spectrum due to specific harvesting of different light spectra, hence complementary chromatic adaptation of communities. This short retrospective highlights this piece of literature that represents an early step toward our current understanding of ecological competition for light spectra.

Acoustic competition within a tropical bird community: the case of the Resplendent QuetzalPharomachrus mocinnoin Guatemala

ABSTRACTThe structure of ecological communities is thought to be mainly driven by competition processes between species. One special case of resource shaping community dynamics is the acoustic space. However, the acoustic communities have been rarely described for tropical birds. Here, we aimed at estimating acoustic competition between the iconic speciesPharomachrus mocinnoand the other bird species occupying the same habitat. An acoustic survey was conducted in a cloud forest in Guatemala for 17 days in six simultaneous recording sites. All species occurring in the same frequency bandwidth were identified, and the acoustic overlapping betweenP. mocinnoand these species was estimated. Eighteen species were identified as acoustic competitors. Ecological traits and phylogenetic distance were defined for all species. The rate of acoustic competition betweenP. mocinnoand other species was related to different ecological traits and competition for resources. The acoustic overlap was high with species competing for similar food resources and phylogenetically close species and low with predator species and phylogenetically distant species. These unique observations provide new behavioural and ecological information that might be useful for the knowledge of this species and the cloud forest.

A Green Technological Innovation Efficiency Evaluation of Technology-Based SMEs Based on the Undesirable SBM and the Malmquist Index: A Case of Hebei Province in China

Small- and medium-sized technology-based enterprises (technology-based SMEs) are an important part of China’s scientific and technological development. To a certain extent, the green technological innovation level of technology-based SMEs plays a significant role in supporting the overall development of social green innovation. Carrying out research on green technology innovation efficiency evaluations of technology-based SMEs is helpful to find existing problems to provide references for managers. Therefore, this paper proposes an evaluation system based on the undesirable slack based model (SBM) and the Malmquist index model. Firstly, the evaluation index system of the green technological innovation efficiency of technology-based SMEs in Hebei Province was constructed from the perspectives of input and output, in which environmental pollution is included in the evaluation factors of green innovation activities. Then, the undesirable SBM and the Malmquist index model of green technology innovation efficiency evaluation were constructed. Finally, the technological innovation efficiency of technology-based SMEs in Hebei Province in different regions and time nodes was comprehensively calculated and combined with the Malmquist index model to analyze the efficiency changes of technology-based SMEs in Hebei Province over different years. The results show that the overall level of green technological innovation efficiency of technology-based SMEs in Hebei Province is low, and the regional differences in various cities are obvious, but the main trend is rising. The research in this paper can further improve the research results in the field of evaluation of technology-based SMEs and technological innovation efficiency, as well as play an important role in improving the ecological competitiveness and sustainable development capabilities of the products of Hebei’s technology-based SMEs.

Multiple‐model stock assessment frameworks for precautionary management and conservation on fishery‐targeted coastal dolphin populations off Japan

Abstract Stock assessment approaches are often oversimplified due to lack of biological knowledge and insufficient data. In spite of world‐wide attention, fishery‐targeted coastal dolphin species in Japan have lacked in‐depth quantitative stock assessments because of limited time series of population size and an absence of associated biological information. We consequently developed integrated population models that analysed multiple sources of data simultaneously with published biological information within a Bayesian framework. We estimate population status and trends for three main species targeted by fisheries, bottlenose dolphins Tursiops truncatus, Risso's dolphins Grampus griseu, and short‐finned pilot whales Globicephala macrorhynchus, using single‐species age‐aggregated and age‐structured population dynamics models. Models were fit to absolute abundance estimates from systematic line‐transect surveys, four series of abundance indices calculated from fisher's logbooks, and historical catch records. Published biological information was used to develop prior distributions for the biological parameters. We assessed the possible effects of ecological disturbance and competition using state‐space and multispecies models. The multispecies model was selected by the model selection both for the age‐aggregated and the age‐structured approaches. Single‐species assessments found that population size declined 4.2% (Risso's dolphin) to 8.0% (bottlenose dolphin) for three species since the late 1800s based on median posterior values, while the state‐space and multispecies models found that environmental disturbance and an interaction among species could have reduced population size more substantially. Policy implications. Simple single‐species models are often used to provide conservation and management advice for wild animals but, in this case, results from such models are overly optimistic because they overlook important ecological process. In contrast, current population status could be less favorable if environmental disturbance and interspecific competition actually control population dynamics. Even if that is not the case, considering ecological process in the model will provide more precautionary ways. Our approach of combining multiple modelling frameworks is applicable to many other management systems, and offers increased confidence in estimated status and trends over assessments that consider only a single model.

Broad‐scale patterns of geographic avoidance between species emerge in the absence of fine‐scale mechanisms of coexistence

AbstractAimThe need to forecast range shifts under future climate change has motivated an increasing interest in better understanding the role of biotic interactions in driving diversity patterns. The contribution of biotic interactions to shaping broad‐scale species distributions is, however, still debated, partly due to the difficulty of detecting their effects. We aim to test whether spatial exclusion between potentially competing species can be detected at the species range scale, and whether this pattern relates to fine‐scale mechanisms of coexistence.LocationWestern Palearctic.MethodsWe develop and evaluate a measure of geographic avoidance that uses outputs of species distribution models to quantify geographic exclusion patterns expected if interspecific competition affects broad‐scale distributions. We apply the measure to 10 Palearctic bat species belonging to four morphologically similar cryptic groups in which competition is likely to occur. We compare outputs to null models based on pairs of virtual species and to expectations based on ecological similarity and fine‐scale coexistence mechanisms. We project changes in range suitability under climate change taking into account effects of geographic avoidance.ResultsValues of geographic avoidance were above null expectations for two cryptic species pairs, suggesting that interspecific competition could have contributed to shaping their broad‐scale distributions. These two pairs showed highest levels of ecological similarity and no trophic or habitat partitioning. Considering the role of competition modified predictions of future range suitability.Main conclusionsOur results support the role of interspecific competition in limiting the geographic ranges of morphologically similar species in the absence of fine‐scale mechanisms of coexistence. This study highlights the importance of incorporating biotic interactions into predictive models of range shifts under climate change, and the need for further integration of community ecology with species distribution models to understand the role of competition in ecology and biogeography.

Method for modelling ecological competition based on Pareto optimality: A case study of coastal wetlands in Jiangsu Province, China

Competition is an important factor in determining the evolution of ecosystem population (or community) structure and the change in system functions, which are usually manifested directly at the system structure level. From the perspective of ecosystem services, based on the Pareto optimisation theory, we selected the coastal area of Jiangsu, China as the study area and carried out a study of equivalent competition among ecosystem populations (or communities). Firstly, we divided the study area into the region with nature reserve (NRR) and the region without nature reserve (Non-NRR). The study was performed through clarifying the ‘structure–process–function–service’ cascade relationship of the ecosystem and quantifying the value of major ecosystem services. Then, based on the theory of competition/coexistence, considered the population (or community) in the regional complex ecosystem as the object, we used the reference point-based non-dominated sorting (NSGA-III) algorithm to simultaneously optimise each ecosystem service to obtain a compromised Pareto optimal solution set. Finally, the technique for order preference by similarity to an ideal solution (TOPSIS) was used as a comprehensive evaluation method based on the criteria importance through inter-criteria correlation (CRITIC) weighting method for multi-objective decision-making to obtain the optimal balance of regional ecosystem services. The optimal balance implies that various groups can not only ensure that their own service values are maximised but also interact with other groups to maintain a state of synergistic competition and common development. The results showed that the characteristics of ecological services values under the optimal balance state of the coastal areas in Jiangsu are compatible with the regional ecological conditions; the dominant service types (and their proportion of the total value in NRR and Non-NRR) are carbon fixation (50.70 and 50.23%), climate regulation (13.29 and 12.34%), food production (8.40 and 10.90%), water supply (8.83 and 6.60%), gas regulation (7.72 and 8.73%), and flood storage (4.95 and 5.24%). Compared to the current average service value, this status has increased by 38.61% and 23.60% respectively, in NRR and Non-NRR. The corresponding optimal population (or community) structure (and the area ratio of each population in the two regions) is dominated by forest land (40.62 and 28.74%), paddy fields (24.16 and 37.44%) and meadows (9.42 and 10.70%), and the coastal wetland populations primarily including reeds (9.78 and 3.59%), aquaculture water bodies (7.46 and 3.86%) and Spartina (3.32 and 5.60%). The structural characteristics are consistent with the development law of ecological competition and succession of the coastal wetland system in this region and the direction of ecological service value optimization. The ideas and methods proposed in this study can provide a new direction for ecological competition research.

Pulchelloid A, a sesquiterpene lactone from the Canadian prairie plant Gaillardia aristata inhibits mitosis in human cells.

The Canadian prairie ecosystem presents a rich source of natural products from plants that are subjected to herbivory by grazing mammals. This type of ecological competition may contribute to the production of natural products of interest in cell biology and medical research. We provide the first biological description of the sesquiterpene lactone, pulchelloid A, which we isolated from the prairie plant, Gaillardia aristata (Asteraceae) and report that it inhibits mitosis in human cells. We found that G. aristata (Blanket flower) extracts were cytotoxic to human cell lines and used phenotypic assays to characterize the bioactivity of extracts. Before dying, cells were characterized by a rounded morphology, phospho-histone H3 signals, mitotic spindles, and active Cdk1. By biology-guided fractionation of Gaillardia extracts, we isolated a sesquiterpene lactone named pulchelloid A. We used immunofluorescence microscopy and observed that cells treated with pulchelloid A have phospho-histone H3 positive chromosomes and a mitotic spindle, confirming that they were in mitosis. Treated cells arrest with an unusual phenotype; they enter a prolonged mitotic arrest in which the spindles become multipolar and the chromosomes acquire histone γH2AX foci, a hallmark of damaged DNA. We propose that pulchelloid A, a natural product present in the prairie plant Gaillardia aristata, delays cells in mitosis. There is a growing body of evidence that a small number of members of the sesquiterpene lactone chemical family may target proteins that regulate mitosis.

Impact of China's COVID-19 prevention and control efforts on outbreaks of influenza

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a serious public health burden. As the COVID-19 epidemic in China would coincide with a seasonal outbreak of influenza, there were serious concerns about whether influenza would be aggravated by the SARS-CoV-2 infection and COVID-19 pandemic. This article provides a brief overview of the impacts of the COVID-19 epidemic on influenza activity in China. The percentage of positive influenza tests decreased during the COVID-19 pandemic. During the first stage of the COVID-19 outbreak, the percentage of positive influenza tests reached to a peak of 47.7%. At the second stage, the percentage of positive influenza tests was dramatically decreased from 40.4% to 14.0%. Thereafter, it remains at a low level of less than 6.2%. In addition, the possible causes of this phenomenon have been summarized, including prevention and control measures and ecological competition. Lastly, this article suggests that the public health approach to preventing COVID-19 may also help to control other respiratory infectious diseases. Public health measures need to be maintained even in the later stages of the COVID-19 epidemic.

Evaluating the post-fire natural regeneration of Mediterranean-type scrublands in Central Spain

We performed a five-year assessment of the natural vegetation restoration capacity following the 2012 fires in Valdemaqueda (Madrid, Spain) via the characterization of the post-fire and residual vegetation and the analysis of soil physico-chemical characteristics. Six pilot-plots were established in the affected site. Forest species, representative of the potential natural vegetation of the area (Juniperus oxycedrus subsp. lagunae and Quercus rotundifolia woodlands) and broom shrubs (Cytisus scoparius, Retama sphaerocarpa) were planted to assess the relationship among the stages of ecological succession, competition, and soil restoration processes following devastating fire events.
 The fire-driven alteration of the soil’s physico-chemical properties was evident, given the increased pH and reduced C/N ratio in the first years of the study. However, we observed an increased soil enrichment in the last years of study, accompanied by the propagation of herbaceous species, su[1]pporting our seed bank findings, showing a clear difference in the sprouting rate between burnt and control plots (80% vs. 20%, respectively). The establishment of robust, pyrophyte shrub species (Cistus ladanifer, C. laurifolius, Rosmarinus officinalis) rather than natural succession evidenced the clear conversion of the vegetation in burnt areas. These findings in the pilot-plots allowed evidencing the high vulnerability of the natural vegetation to the settling of pyrophytes, given their low survival rate under the strong competitive pressure of these pyrophytic species. The proliferation of these pyrophytes could translate into changes in soil macro- and microbiota, nutrient dynamics, species diversity, and interaction, added to the alteration of fire regimes in the area. Overall, these results highlight the risk for soil impoverishment and possible erosion of the fire-affected sites. Moreover, they underline the importance of the establishment and regeneration of Genisteae species to outcompete pioneer pyrophytic species, favoring the restoration of the area’s potential natural vegetation

The Major Roles of Climate Warming and Ecological Competition in the Small-scale Coastal Fishery in French Guiana

Marine ecosystems, biodiversity, and fisheries are under strain worldwide due to global changes including climate warming and demographic pressure. To address this issue, many scientists and stakeholders advocate the use of an ecosystem approach for fisheries that integrates the numerous ecological and economic complexities at play rather than focusing on the management of individual target species. However, the operationalization of such an ecosystem approach remains challenging, especially from a bio-economic standpoint. Here, to address this issue, we propose a model of intermediate complexity (MICE) relying on multi-species, multi-fleet, and resource-based dynamics. Climate change effects are incorporated through an envelope model for the biological growth of fish species as a function of sea surface temperature. The model is calibrated for the small-scale fishery in French Guiana using a time series of fish landings and fishing effort from 2006 to 2018. From the calibrated model, a predictive fishing effort projection and RCP climate scenarios derived from IPCC, we explore the ecosystem dynamics and the fishery production at the horizon 2100. Our results demonstrate the long-term detrimental impact of both climate change and ecological competition on fish biodiversity. The prognosis is particularly catastrophic under the most pessimistic climate scenario, with a potential collapse of both biomass targeted species and fishing activity by 2100.

An Empirical Study on the Coupling Coordination Relationship between Cultural Tourism Industry Competitiveness and Tourism Flow

The case study for this analysis is Henan province in China, where sustainability is a central issue for tourism development due to the area’s enormous and unexploited potential for cultural tourism. We construct a cultural tourism industry competitiveness evaluation index from cultural resource competitiveness, economic development support competitiveness, ecological environment competitiveness and basic guarantee competitiveness, and also construct a tourism flow evaluation index from tourist flow, consumption flow and effect flow. For this study, we then adopt an Entropy-TOPSIS and Coupling Coordination model to analyze the characteristics of coupling and coordinated development of them from 2009 to 2019. The empirical results show that (1) the comprehensive development index of cultural tourism industry competitiveness and tourism flow exhibits a fluctuating rise trend and maintains good development momentum; and (2) the coupling coordination degree between the cultural tourism industry competitiveness and tourism flow in Henan Province as a whole is gradually improving and the coupling coordination level developed from extreme disorder to grudging coordination, but it is unpromising in some parts of cities. Some recommendations are provided to promote the coupling and coordinated development of cultural tourism industry competitiveness and tourism flow for cities.

Convergent character displacement in sympatric tamarin calls (Saguinus spp.)

Character displacement, or a shift in traits where species co-occur, is one of the most common ecological patterns to result from interactions between closely related species. Usually, character displacement is associated to divergence in traits, though, they might be convergent, especially when used for aggressive interference between species. In the context of animal communication, territorial calls are predicted to converge in order to increase context recognition and decrease the costs of ecological interference competition. However, such signals might also be adapted to characteristics of the shared environment. In this study, we used data from 15 groups of two parapatric tamarins, Saguinus midas and S. bicolor, to test for similarities in long calls among sympatric and allopatric groups. We hypothesized that calls would converge in sympatric areas, as it would be mutually beneficial if both species recognize territorial contexts, but that convergence would depend on forest type due to acoustic adaptation. As predicted, long calls converged in sympatry, with S. midas shifting its calls towards S. bicolor’s acoustic pattern. However, this shift only occurred in primary forest. In sympatric areas, S. midas produced sounds with narrower bandwidths in primary than in secondary forest, consistent with optimization of sound propagation while both species produced longer calls in primary forests independently of geographic location (i.e. sympatry and allopatry). Our results suggest that both social and environmental pressures are important in shaping tamarin sounds. As their effects can interact, analyses, which assume that these ecological pressures act independently, are likely to miss important patterns. Territorial signals between closely related sympatric species are expected to be convergent to increase context recognition and decrease the costs of interference competition. However, such signals might also be adapted to characteristics of the shared environment, such as forest structure characteristics. We analysed vocalisations from two parapatric tamarins and found that, though their long calls asymmetrically converged in sympatry, only red-handed tamarins shifted towards pied tamarin call type, and this only occurred in primary forest. Our results suggest that both social and environmental pressures are important in shaping primate calls. Because their effects can interact, analyses which assume that these pressures act independently, are likely to miss important patterns.

Research on accuracy of field patrol data based on GIS

Field patrol is the main method of wildlife protection, which plays a very important role in the protection and management of natural resources and biodiversity in nature reserves. However, it is difficult to completely evaluate the patrol accuracy, because it is impossible to preset the animal site in advance. Based on patrol data collected from the First Ecological Guard Competition, the accuracy of patrol route, animal site and geographical factor of animal site and GIS method are evaluated and analyzed. The results show that: (1) the patrol route has the highest accuracy, and the average accuracy is 87.91%, which indicates that ranger could basically patrol according to the preset patrol route; (2) the accuracy of animal site is not as good as that of patrol route, and the average accuracy is 51.10%, mainly because recorded animals are not right, standardized and complete; (3) the altitude accuracy is high, the slope accuracy is very low. It is recommended that slope data would no longer be recorded in the future and be directly obtained by GIS method. The results are helpful to improve the patrol accuracy evaluation system.

Characteristics and consequences of a disease outbreak in aquatic insects

Abstract Disease can be a powerful driver of population and community dynamics, as well as evolutionary processes. Disease is also emerging at increasing rates, resulting in massive impacts on populations, communities, and ecosystems. However, assessing these impacts requires foundational knowledge of disease agents and hosts, which is often lacking, particularly in aquatic insects. We describe a recent disease outbreak in caddisflies, suggesting potential consequences for population and community dynamics of the host. We use a series of complementary studies to develop a cohesive foundation of information about this disease, including identification using genomic methods, observational prevalence studies, laboratory experiments to establish transmissibility and fitness consequences, and laboratory and field investigations to infer transmission mechanisms. We identified the infection as being caused by the oomycete Saprolegnia—the first time this parasite has been noted in insect eggs. Prevalence surveys found high prevalence (up to 36%) with variation across space, time, and host species. We demonstrated increasing egg mortality with increasing infection within an egg mass (every 10% increase in infection rate doubles odds of mortality), thereby confirming disease. We established transmissibility and show that transmission occurs through both direct contact with infected egg masses and from background sources, which probably interact to create complex patterns of disease. Taken together, our findings show that conditions necessary for population and community consequences are present. Specifically, increased mortality rates almost certainly occurred during the outbreak, yielding lower larval numbers and potentially altering community interactions. Transmission by contact between egg masses combined with observed species‐specific prevalence suggest shifts in the relative performance of different species because of interactions between host and parasite life histories. Outside extreme examples such as chytrid fungus, disease has traditionally received less interest than resource competition or predation in community ecology, although disease ecology is advancing rapidly. One major hurdle is a lack of foundational knowledge characterising disease processes in natural communities, particularly in aquatic insects. Our findings highlight the importance of investigating diseases in insect eggs and provide the foundation for further investigations of how these processes play out at the population and community scale.

Side Effects of Insecticides on Leaf-Miners and Gall-Inducers Depend on Species Ecological Traits and Competition with Leaf-Chewers.

Internal feeding is considered to shield sessile herbivorous insects from exposure to nonsystemic insecticides aerially sprayed against forest defoliators, although this has not been tested. It is, however, established that leaf damage caused by defoliators affects the survivorship and oviposition behavior of sessile herbivores. Thus feeding ecology and competition may mediate nontarget effects of insecticides on these insects. We tested the ecological sensitivity of 3 guilds of sessile herbivores (upper-surface leaf-miners, lower-surface leaf-miners, and gall-inducers) to the lipophilic larvicides diflubenzuron and tebufenozide aerially applied either at operational rates (12 g active ingredient [a.i.]/ha and 69.6 g [a.i.]/ha, respectively) or at maximum legal rates (60 g [a.i.]/ha and 180 g [a.i.]/ha, respectively), in German oak forests. Diflubenzuron affected leaf-miners at different life stages depending on their position on the leaf but had no effect on gall-inducers. Tebufenozide showed a similar, but not significant, pattern in leaf-miners and did not affect gall-inducers. By reducing the incidence of chewing damage on leaves, both insecticides offset the negative effect of competition on leaf-miner and gall-inducers. The net outcome of insecticide treatment was positive for guilds avoiding exposure, but negative for upper-surface leaf-miners. Exposure to insecticides in situ can be mediated by subtle differences in species biology and species interactions, with potential implications for organisms usually considered safe in risk assessment studies. Environ Toxicol Chem 2021;00:1-17. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Pneumococcal Competition Modulates Antibiotic Resistance in the Pre-Vaccination Era: A Modelling Study.

The ongoing emergence of antibiotic resistant strains and high frequencies of antibiotic resistance of Streptococcus pneumoniae poses a major public health challenge. How and which ecological and evolutionary mechanisms maintain the coexistence of antibiotic resistant and susceptible strains remains largely an open question. We developed an individual-based, stochastic model expanding on a previous pneumococci modelling framework. We explore how between- and within-host mechanisms of competition can sustain observed levels of resistance to antibiotics in the pre-vaccination era. Our framework considers that within-host competition for co-colonization between resistant and susceptible strains can arise via pre-existing immunity (immunological competition) or intrinsic fitness differences due to resistance costs (ecological competition). We find that beyond stochasticity, population structure or movement, competition at the within-host level can explain observed resistance frequencies. We compare our simulation results to pneumococcal antibiotic resistance data in the European region using approximate Bayesian computation. Our results demonstrate that ecological competition for co-colonization can explain the variation in co-existence of resistant and susceptible pneumococci observed in the pre-vaccination era. Furthermore, we show that within-host pneumococcal competition can facilitate the maintenance of resistance in the pre-vaccination era. Accounting for these competition-related components of pneumococcal dynamics can improve our understanding of drivers for the emergence and maintenance of antibiotic resistance in pneumococci.