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1.
Global Health ; 20(1): 70, 2024 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-39358716

RESUMEN

BACKGROUND AND METHODS: Competition regulation has a strong influence on the relative market power of firms. As such, competition regulation can complement industry-specific measures designed to address harms associated with excessive market power in harmful consumer product industries. This study aimed to examine, through a public health lens, assessments and decisions made by competition authorities in four jurisdictions (Australia, South Africa, the United States (US), and the European Union (EU)) involving three harmful consumer product industries (alcoholic beverages, soft drinks, tobacco). We analysed legal case documents, sourced from online public registers and dating back as far as the online records extended, using a narrative approach. Regulatory decisions and harms described by the authorities were inductively coded, focusing on the affected group(s) (e.g., consumers) and the nature of the harms (e.g., price increases) identified. RESULTS: We identified 359 cases published by competition authorities in Australia (n = 202), South Africa (n = 44), the US (n = 27), and the EU (n = 86). Most cases (n = 239) related to mergers and acquisitions (M&As). Competition authorities in Australia, the US, and the EU were found to make many decisions oriented towards increasing the affordability and accessibility of alcohol beverages, soft drinks, and tobacco products. Such decisions were very often made despite the presence of consumption-reduction public health policies. In comparison, South Africa's competition authorities routinely considered broader issues, including 'Black Economic Empowerment' and potential harms to workers. CONCLUSION: Many of the competition regulatory decisions assessed likely facilitated the concentration of market power in the industries we explored. Nevertheless, there appears to be potential for competition regulatory frameworks to play a more prominent role in promoting and protecting the public's health through tighter regulation of excessive market power in harmful consumer product industries.


Asunto(s)
Competencia Económica , Unión Europea , Humanos , Sudáfrica , Estados Unidos , Australia , Bebidas Alcohólicas , Bebidas Gaseosas , Industria del Tabaco/legislación & jurisprudencia , Salud Pública/legislación & jurisprudencia , Toma de Decisiones , Análisis de Documentos
2.
J Anim Ecol ; 2024 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-39367545

RESUMEN

Droughts are increasing in frequency and severity globally due to climate change, leading to changes in resource availability that may have cascading effects on animal ecology. Resource availability is a key driver of animal space use, which in turn influences interspecific interactions like intraguild competition. Understanding how climate-induced changes in resource availability influence animal space use, and how species-specific responses scale up to affect intraguild dynamics, is necessary for predicting broader community-level responses to climatic changes. Although several studies have demonstrated the ecological impacts of drought, the behavioural responses of individuals that scale up to these broader-scale effects are not well known, particularly among animals in top trophic levels like large carnivores. Furthermore, we currently lack understanding of how the impacts of climate variability on individual carnivore behaviour are linked to intraguild dynamics, in part because multi-species datasets collected at timescales relevant to climatic changes are rare. Using 11 years of GPS data from four sympatric large carnivore species in southern Africa-lions (Panthera leo), leopards (Panthera pardus), African wild dogs (Lycaon pictus) and cheetahs (Acinonyx jubatus)-spanning 4 severe drought events, we test whether drought conditions impact (1) large carnivore space use, (2) broad-scale intraguild spatial overlap and (3) fine-scale intraguild interactions. Drought conditions expanded space use across species, with carnivores increasing their monthly home range sizes by 35% (wild dogs) to 66% (leopards). Drought conditions increased the amount of spatial overlap between lions and subordinate felids (cheetahs and leopards) by up to 119%, but only lion-cheetah encounter rates were affected by these changes, declining in response to drought. Our findings reveal that drought has a clear signature on the space use of multiple sympatric large carnivore species, which can alter spatiotemporal partitioning between competing species. Our study thereby illuminates the links between environmental change, animal behaviour and intraguild dynamics. While fine-scale avoidance strategies may facilitate intraguild coexistence during periodic droughts, large carnivore conservation may require considerable expansion of protected areas or revised human-carnivore coexistence strategies to accommodate the likely long-term increased space demands of large carnivores under projected increases in drought intensity.

3.
Front Psychol ; 15: 1268734, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39359958

RESUMEN

The introduction of competition has the potential to enhance the efficacy of students' learning performance. Nevertheless, there have been contradictory findings about the impact of intergroup competition on students' learning performance and engagement. Therefore, further comprehensive investigations for this problem are necessary. In order to bridge this gap, the present study seeks to ascertain the efficacy of intergroup competition in relation to students' academic performance and motivation. Consequently, we present the concept of intergroup competition and implement it within the context of an online programming course and an online Chinese-English translation course. The participants of this study consist of sophomore students majoring in Computer Science and English. Initially, a total of 108 sophomore students majoring in Computer Science participated. Then, a total of 100 sophomore students majoring in English participated. A quasi-experimental study was subsequently undertaken to compare students from two courses, which are online programming and Chinese-English translation, assigning them to an experimental group and a comparison group, respectively. Then, we conducted independent samples t-tests to measure the difference between the academic performance of the two group of students from two courses. The results indicate that both groups of students who were exposed to the intergroup competition mechanism demonstrated considerably higher levels of academic performance and engagement compared to the other group of students. The findings indicate that the competition mechanism, has the potential to be a beneficial instrument for enhancing both students' learning performance and motivation.

4.
Emerg Microbes Infect ; : 2412990, 2024 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-39361729

RESUMEN

A multitude of functional mutations continue to emerge on the N-terminal domain (NTD) of the spike protein in SARS-CoV-2 Omicron subvariants. Understanding the immunogenicity of Omicron NTD and the properties of antibodies elicited by it is crucial for comprehending the impact of NTD mutations on viral fitness and guiding vaccine design. In this study, we find that most of NTD-targeting antibodies isolated from individuals with BA.5/BF.7 breakthrough infection (BTI) are ancestral (wildtype or WT)-reactive and non-neutralizing. Surprisingly, we identified five ultra-potent neutralizing antibodies (NAbs) that can only bind to Omicron but not WT NTD. Structural analysis revealed that they bind to a unique epitope on the N1/N2 loop of NTD and interact with the receptor-binding domain (RBD) via the light chain. These Omicron-specific NAbs achieve neutralization through ACE2 competition and blockage of ACE2-mediated S1 shedding. However, BA.2.86 and BA.2.87.1, which carry insertions or deletions on the N1/N2 loop, can evade these antibodies. Together, we provided a detailed map of the NTD-targeting antibody repertoire in the post-Omicron era, demonstrating their vulnerability to NTD mutations enabled by its evolutionary flexibility, despite their potent neutralization. These results revealed the function of the indels in the NTD of BA.2.86/JN.1 sublineage in evading neutralizing antibodies and highlighted the importance of considering the immunogenicity of NTD in vaccine design.

5.
Ecol Lett ; 27(9): e14506, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39354892

RESUMEN

Conspecific density dependence (CDD) in plant populations is widespread, most likely caused by local-scale biotic interactions, and has potentially important implications for biodiversity, community composition, and ecosystem processes. However, progress in this important area of ecology has been hindered by differing viewpoints on CDD across subfields in ecology, lack of synthesis across CDD-related frameworks, and misunderstandings about how empirical measurements of local CDD fit within the context of broader ecological theories on community assembly and diversity maintenance. Here, we propose a conceptual synthesis of local-scale CDD and its causes, including species-specific antagonistic and mutualistic interactions. First, we compare and clarify different uses of CDD and related concepts across subfields within ecology. We suggest the use of local stabilizing/destabilizing CDD to refer to the scenario where local conspecific density effects are more negative/positive than heterospecific effects. Second, we discuss different mechanisms for local stabilizing and destabilizing CDD, how those mechanisms are interrelated, and how they cut across several fields of study within ecology. Third, we place local stabilizing/destabilizing CDD within the context of broader ecological theories and discuss implications and challenges related to scaling up the effects of local CDD on populations, communities, and metacommunities. The ultimate goal of this synthesis is to provide a conceptual roadmap for researchers studying local CDD and its implications for population and community dynamics.


Asunto(s)
Biodiversidad , Plantas , Densidad de Población , Dinámica Poblacional , Fenómenos Fisiológicos de las Plantas , Simbiosis , Ecosistema
6.
Ecol Lett ; 27(9): e14503, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39354908

RESUMEN

Plant-soil feedback (PSF), the reciprocal interaction between plants and their soil environment, is a fundamental ecological process that can influence coexistence and functional structure in plant communities. Current theory establishes that PSF may enhance diversity or lead to exclusion depending on whether soil conditioning disproportionately benefits heterospecific or conspecific individuals. However, a more complete picture of the impact of PSF requires understanding how PSF interacts with competition. To that end, here we propose an integrated mathematical model combining trait-based competition and soil-explicit PSF. Contrary to the current paradigm, we find that soil conditioning that disproportionately favours conspecific individuals can promote coexistence. Additionally, we show that priority effects are common when soil-conditioning species differ in their edaphic preferences. These effects can allow species with large differences in competitive ability to coexist under certain soil conditions. Our results provide testable predictions tying community-level functional patterns in plant communities to PSF and competition.


Asunto(s)
Modelos Biológicos , Suelo , Plantas , Ecosistema , Fenómenos Fisiológicos de las Plantas
7.
Ecology ; : e4406, 2024 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-39354663

RESUMEN

Ecological forecasting models play an increasingly important role for managing natural resources and assessing our fundamental knowledge of processes driving ecological dynamics. As global environmental change pushes ecosystems beyond their historical conditions, the utility of these models may depend on their transferability to novel conditions. Because species interactions can alter resource use, timing of reproduction, and other aspects of a species' realized niche, changes in biotic conditions, which can arise from community reorganization events in response to environmental change, have the potential to impact model transferability. Using a long-term experiment on desert rodents, we assessed model transferability under novel biotic conditions to better understand the limitations of ecological forecasting. We show that ecological forecasts can be less accurate when the models generating them are transferred to novel biotic conditions and that the extent of model transferability can depend on the species being forecast. We also demonstrate the importance of incorporating uncertainty into forecast evaluation with transferred models generating less accurate and more uncertain forecasts. These results suggest that how a species perceives its competitive landscape can influence model transferability and that when uncertainties are properly accounted for, transferred models may still be appropriate for decision making. Assessing the extent of the transferability of forecasting models is a crucial step to increase our understanding of the limitations of ecological forecasts.

8.
Int J Sports Physiol Perform ; : 1-6, 2024 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-39353578

RESUMEN

PURPOSE: To investigate race-management strategies over a longitudinal case study of one of the world's best female swimmers of the 200-m freestyle to understand if only 1 race-management strategy allowed her to succeed or whether several profiles have been used over the 8 years of analysis. METHODS: Different race-management strategies within and between 50-m laps emerged from cluster analysis. To better explain race management, additional characteristics described the level of adversity, the level of competition, the performance outcome, and the type of race. RESULTS: Two strategies of race management between laps have been used, and both allowed her to succeed in her career. The first was characterized by a fast start and a greater decrease of the speed between laps, whereas the second exhibited a more stable speed management. When those strategies were examined in relation to the level of competition and the level of adversity, it appeared that the first strategy was used more in international competitions and associated with higher time intervals between the studied swimmer and the direct rivals, while the second one was used more in national competitions and associated with lower time intervals. CONCLUSIONS: Findings suggested that this top elite swimmer did not adhere to a single "ideal" race-management strategy. Instead, she demonstrated flexibility and the ability to adapt her race management to contextual factors throughout her career, effectively controlling adversity. This highlights the importance of including adversity analysis in race-management studies.

9.
Front Plant Sci ; 15: 1398060, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39354944

RESUMEN

Inbreeding depression is a key factor regulating the evolution of self-fertilization in plants. Despite predictions that inbreeding depression should evolve with selfing rates as deleterious alleles are increasingly exposed and removed by selection, evidence of purging the genetic load in wild populations is equivocal at best. This discordance could be explained, in part, if the load underlying inbreeding depression is subject to soft selection, i.e., the fitness of selfed individuals depends on the frequency and density of selfed vs. outcrossed individuals in the population. Somewhat counterintuitively, this means that populations with contrasting mutation load can have similar fitness. Soft selection against selfed individuals may be expected when there is inbreeding depression for competitive ability in density-regulated populations. We tested population-level predictions of inbreeding depression in competitive ability by creating a density series of potted plants consisting of either purely outcrossed, purely selfed, or mixed (50% outcrossed, 50% selfed) seed of the mixed-mating biennial Sabatia angularis (Gentianaceae) representing ecological neighborhoods. Focusing on the growth and survival of juveniles, we show that mean plant size is independent of neighborhood composition when resources are limiting, but greatest in outcrossed neighborhoods at low densities. Across a range of densities, this manifests as stronger density-dependence in outcrossed populations compared to selfed or mixed ones. We also found significantly greater size inequalities among individuals in mixed neighborhoods, even at high densities where mean juvenile size converged, a key signature of asymmetric competition between outcrossed and selfed individuals. Our work illustrates how soft selection could shelter the genetic load underlying inbreeding depression and its demographic consequences.

10.
R Soc Open Sci ; 11(10): 240870, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39359457

RESUMEN

Competitive dietary and morphological divergence among co-occurring species are fundamental aspects of ecological communities, particularly on islands. Cabo Verde (~570 km west of continental Africa) hosts several endemic reptiles descended from common ancestors, with sympatric species exhibiting wide morphological variation and competing for limited resources. To explore the mechanisms of resource partitioning between coexisting species, DNA metabarcoding was used to compare the diets of large and small skinks, Chioninia vaillantii and Chioninia delalandii, in sympatric and allopatric contexts on Fogo Island and in a more competitive context on the small and resource-poor Cima Islet. The morphological variation of all populations was also examined to test the character displacement hypothesis and to compare the effect of different competitive scenarios. Results showed significant differences in diet and linear measurements between species and populations. The two sympatric populations of C. delalandii on Fogo and Cima showed similar changes in head morphology compared to the allopatric population, supporting character displacement. The effect of higher competitive pressure on Cima was evidenced by the increased morphological and dietary variation observed. This study demonstrates how sister species develop dietary adaptations/morphologies to maintain stable coexistence, especially in highly competitive scenarios, providing useful insights for effective conservation strategies.

11.
Ecol Appl ; : e3038, 2024 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-39363393

RESUMEN

Compensatory density-dependent (DD) processes play an integral role in fisheries management by underpinning fundamental population demographics. However, DD processes are often assessed only for specific life stages, likely resulting in misleading evaluations of population limitations. Here, we assessed the relative roles of intra- and inter-life stage DD interactions in shaping the population dynamics of perennial freshwater fish with demographically open populations. Specifically, we monitored populations of amphidromous banded kokopu (Galaxias fasciatus), giant kokopu (Galaxias argenteus), and shortjaw kokopu (Galaxias postvectis) in five streams where migratory post-larvae are fished and in three no-take ("closed") streams located on New Zealand's South Island for two years. Using mark-recapture data, we investigated whether fishing altered densities of "small" (non-territorial recruits ≤1-year-old) and "large" (territorial fish >1-year-old) kokopu size classes, and how subsequent density shifts affected the apparent survival and growth of each class while controlling for other confounding factors (e.g., habitat characteristics). We found that closed areas had substantially greater biomass of small kokopu, particularly following the two-month fishing season. Despite this greater influx of recruits, there was no difference in the biomass of large kokopu at the species level, or as a combined assemblage between stream types. This indicated that although fishing of post-larvae reduced recruit influxes into adult habitats, there was no subsequent evidence of recruitment-limitation within adult populations. Instead, kokopu demographics were underpinned by intra- and inter-life stage DD competition and predation. Greater large fish densities played a key role in regulating the survival, growth, and/or presence of various kokopu classes. In contrast, greater small fish densities had positive effects on the growth of opportunistic and insectivorous congeners, likely due to cannibalism and altered foraging behaviors, respectively. Our study details the prominent role of intra- and inter-life stage DD interactions in regulating the population dynamics of perennial migratory freshwater fishes, even in populations with inhibited recruit and juvenile availability. We emphasize the importance for fisheries management to implement recruitment dependencies and complex interactions between distinct life stages to avoid deleterious DD responses and ensure population persistence.

12.
Ecology ; : e4446, 2024 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-39370724

RESUMEN

Why nonnative invasive plant species commonly co-occur, despite their competitive superiority and propensity to displace native species, remains a paradox in invasion biology. Negative interactions among competitively dominant invaders are potentially alleviated by two understudied mechanisms: seasonal priority effects, where phenological separation weakens the effect of competition on species with early phenology; and indirect facilitation, where competition between two species is mitigated by a third species. Although phenological separation has been speculated as a mechanism for explaining co-occurrence patterns of invasive plants, it has never been directly tested. In a greenhouse experiment, we tested the effect of phenological separation on direct and indirect interactions between three co-occurring invasive plant species found in the riparian forests of North America. These species have distinct natural phenological separation with reproduction in early spring (Ficaria verna), mid-spring (Alliaria petiolata), and late summer (Microstegium vimineum). When phenology was experimentally synchronized, direct pairwise interactions among invasive species were overwhelmingly negative, asymmetric, and unlikely to promote co-occurrence. However, increasing phenological separation generated seasonal priority effects, which weakened the effect of competition on species with early phenology. Furthermore, the addition of a third species generated indirect facilitative effects, which balanced competitive outcomes among the two weakest competitors. Based on these findings, we conclude that phenological separation modulates the strength of both seasonal priority effects and indirect facilitation within species interaction networks and may promote the co-occurrence of three common invasive species within this study system. We articulate how future studies can test the external validity of these findings in more complex environmental conditions and with a larger range of invasive plants.

13.
Behav Ecol ; 35(3): arae024, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39372888

RESUMEN

Sex allocation theory predicts that mothers should bias investment in offspring toward the sex that yields higher fitness returns; one such bias may be a skewed offspring sex ratio. Sex allocation is well-studied in birds with cooperative breeding systems, with theory on local resource enhancement and production of helpers at the nest, but little theoretical or empirical work has focused on birds with brood parasitic breeding systems. Wood ducks (Aix sponsa) are a conspecific brood parasite, and rates of parasitism appear to increase with density. Because female wood ducks show high natal philopatry and nest sites are often limiting, local resource competition (LRC) theory predicts that females should overproduce male offspring-the dispersing sex-when competition (density) is high. However, the unique features of conspecific brood parasitism generate alternative predictions from other sex allocation theory, which we develop and test here. We experimentally manipulated nesting density of female wood ducks in 4 populations from 2013 to 2016, and analyzed the resulting sex allocation of >2000 ducklings. In contrast to predictions we did not find overproduction of male offspring by females in high-density populations, females in better condition, or parasitic females; modest support for LRC was found in overproduction of only female parasitic offspring with higher nest box availability. The lack of evidence for sex ratio biases, as expected for LRC and some aspects of brood parasitism, could reflect conflicting selection pressures from nest competition and brood parasitism, or that mechanisms of adaptive sex ratio bias are not possible.

14.
Ann Bot ; 2024 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-39312215

RESUMEN

BACKGROUND AND AIMS: Mixed forest plantations are increasingly recognised for their role in mitigating the impacts of climate change and enhancing ecosystem resilience. Yet, there remains a significant gap in understanding the early-stage dynamics of species trait diversity and interspecies interactions, particularly in pure deciduous mixtures. This study aims to explore the timing and mechanisms by which trait diversity of deciduous species and competitive interactions influence yield, carbon allocation, and space occupation in mixed forests, both above- and belowground. METHODS: A forest inventory was conducted in planted monocultures, 2-species, and 4-species mixtures of European Acer, Tilia, Carpinus, and Quercus, representing a spectrum from acquisitive to conservative tree species. Competition effects were assessed with linear mixed-effects models at the level of biomass and space acquisition, including leaf, canopy, stem, and fine root traits. KEY RESULTS: Early aboveground growth effects were observed six years post-planting, with significant biomass accumulation after eight years, strongly influenced by species composition. Mixtures, especially with acquisitive species, exhibited aboveground overyielding, 1.5- to 1.9-times higher than monocultures. Fine roots showed substantial overyielding in high diversity stands. Biomass allocation was species-specific and varied markedly by tree size, the level of diversity, and between acquisitive Acer and the more conservative species. No root segregation was found. CONCLUSIONS: Our findings underscore the critical role of species trait diversity in enhancing productivity in mixed deciduous forest plantations. Allometric changes highlight the need to differentiate between (active) acclimations and (passive) tree size-related changes, but illustrate major consequences of competitive interactions for the functional relation between leaves, stem, and roots. This study points towards the significant contributions of both above- and belowground components to overall productivity of planted mixed-species forests.

15.
Front Sports Act Living ; 6: 1373481, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39319337

RESUMEN

This study applied grey relational analysis to assess the relationship between individual trampoline event scores and overall performance of top male and female athletes in the 2020 Tokyo Olympics. Analyzing execution, horizontal, difficulty, timing of flight, and total scores, results showed males excelled significantly in difficulty, timing, and overall performance, while execution and horizontal scores were comparable. For males, timing of flight (excluding outliers) had the greatest influence on total score, followed by difficulty and execution. In females, difficulty dominated, followed by timing and horizontal, with execution least impactful. The study highlighted the primary roles of timing and difficulty scores in overall trampoline performance, with gender variations in score contributions. The findings illuminated the interplay of score components, offering a theoretical framework for targeted trampoline training. For international athletes, key considerations included boosting height index for a robust trampoline foundation; tailoring difficulty levels to athletes' abilities while adhering to scoring rules, without sacrificing technical prowess; and sustaining training to refine quality and stability of routines.

16.
Sheng Wu Gong Cheng Xue Bao ; 40(9): 3296-3304, 2024 Sep 25.
Artículo en Chino | MEDLINE | ID: mdl-39319741

RESUMEN

Synthetic Biology, as an emerging discipline, has gained widespread attention and is developing rapidly, profoundly impacting the fields of life sciences and biotechnology. Concurrently, as emerging engineering education programs take shape, accelerated cultivation of multifaceted innovative talents represents a new mission and imperative for higher education in China. In the context of the flourishing development of Synthetic Biology, East China University of Science and Technology has established a curriculum cluster in Synthetic Biology, focusing on microbiological drug discovery and biomanufacturing. The teaching team initially reviewed the curriculum system related to Synthetic Biology and its upstream and downstream courses. Subsequently, they expanded the core courses in Synthetic Biology, creating a curriculum cluster that encompasses not only the theoretical foundations and cutting-edge technologies but also integrates with related disciplines. Moreover, the curriculum cluster leverages lectures from renowned domestic and international professors in the State Key Laboratory of Bioreactor Engineering, and harnesses the rich resources of the Program of Introducing Talents of Discipline to Universities (the "111 plan"), aiming to enhance students' innovation capabilities. With the support of this curriculum cluster and teaching team, undergraduate students actively participate in international Synthetic Biology competitions like international genetic engineering machine competition (iGEM), consistently achieving gold awards. Furthermore, many students have applied for patents and made contributions to research paper publications. This work stands as a valuable exemplar for cultivating multifaceted talents with exceptional innovative capabilities.


Asunto(s)
Curriculum , Biología Sintética , Biología Sintética/educación , China , Universidades , Biotecnología/educación , Descubrimiento de Drogas
19.
Ecol Evol ; 14(9): e70341, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39296735

RESUMEN

One yet unresolved question in the study of mating system evolution is the occurrence of mating failure, when individuals go through their lives without successfully mating. This includes the failure to produce offspring even following copulation, for instance due to insemination or fertilisation failure. Copulations are costly in a variety of ways, but also a fundamental route to fitness in sexual species, and so we should expect that engaging in copulations that generate no offspring should be strongly selected against. Nonetheless, it has become apparent that mating failure is quite common in nature. Here we consider post-copulatory sexual selection in Lygaeus simulans seed bugs to test the hypothesis that the high levels of mating failure found in this species (approximately 40%-60%) are caused by cryptic male choice (i.e. males choosing not to inseminate a female during copulation). In our first experiment, we found that mating failure depended on female size, but not male size, with smaller females experiencing mating failure more frequently. Mechanistically this is likely to be due to copulation duration, as shorter copulations were more likely to lead to mating failure. Likewise, copulations with smaller females were shorter. In our second and third experiments, rates of mating failure decreased when pairs were allowed to repeatedly interact with the same partner over longer durations (hours through to days), implying that mating failure is not primarily caused by infertility or chronic mechanical failure. Instead, our results strongly suggest cryptic male choice as the cause of mating failure in this species.

20.
R Soc Open Sci ; 11(9): 240734, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39309259

RESUMEN

Our understanding of microbial variation in male reproductive tissues is poorly understood, both regarding how it varies spatially across different tissues and its ability to affect male sperm and semen quality. To redress this gap, we explored the relationship between male sperm viability and male gut and reproductive tract microbiomes in the Pacific field cricket, Teleogryllus oceanicus. We selected cohorts of males within our populations with the highest and lowest natural sperm viability and characterized the bacterial microbiota present in the gut, testes, seminal vesicle, accessory glands and the spermatophore (ejaculate) using 16S ribosomal RNA gene metabarcoding. We identified bacterial taxa corresponding to sperm viability, highlighting for the first time an association between the host's microbial communities and male competitive fertilization success. We also found significant spatial variation in bacterial community structure of reproductive tissue types. Our data demonstrate the importance of considering the microbial diversity of both the host gut and reproductive tract when investigating male fertility in wildlife and potentially human clinical settings.

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