Non-random Patterns Research Articles

Identification and Characterization of Short-Term Motor Patterns in Rest Tremor of Individuals with Parkinson's Disease.

(1) Background: The dynamics of hand tremors involve nonrandom and short-term motor patterns (STMPs). This study aimed to (i) identify STMPs in Parkinson's disease (PD) and physiological resting tremor and (ii) characterize STMPs by amplitude, persistence, and regularity. (2) Methods: This study included healthy (N = 12, 60.1 ± 5.9 years old) and PD (N = 14, 65 ± 11.54 years old) participants. The signals were collected using a triaxial gyroscope on the dorsal side of the hand during a resting condition. Data were preprocessed and seven features were extracted from each 1 s window with 50% overlap. The STMPs were identified using the clustering technique k-means applied to the data in the two-dimensional space given by t-Distributed Stochastic Neighbor Embedding (t-SNE). The frequency, transition probability, and duration of the STMPs for each group were assessed. All STMP features were averaged across groups. (3) Results: Three STMPs were identified in tremor signals (p < 0.05). STMP 1 was prevalent in the healthy control (HC) subjects, STMP 2 in both groups, and STMP3 in PD. Only the coefficient of variation and complexity differed significantly between groups. (4) Conclusion: These results can help professionals characterize and evaluate tremor severity and treatment efficacy.

Seizure forecasting using machine learning models trained by seizure diaries

Objectives. People with refractory epilepsy are overwhelmed by the uncertainty of their next seizures. Accurate prediction of future seizures could greatly improve the quality of life for these patients. New evidence suggests that seizure occurrences can have cyclical patterns for some patients. Even though these cyclicalities are not intuitive, they can be identified by machine learning (ML), to identify patients with predictable vs unpredictable seizure patterns. Approach. Self-reported seizure logs of 153 patients from the Human Epilepsy Project with more than three reported seizures (totaling 8337 seizures) were used to obtain inter-seizure interval time-series for training and evaluation of the forecasting models. Two classes of prediction methods were studied: (1) statistical approaches using Bayesian fusion of population-wise and individual-wise seizure patterns; and (2) ML-based algorithms including least squares, least absolute shrinkage and selection operator, support vector machine (SVM) regression, and long short-term memory regression. Leave-one-person-out cross-validation was used for training and evaluation, by training on seizure diaries of all except one subject and testing on the left-out subject. Main results. The leading forecasting models were the SVM regression and a statistical model that combined the median of population-wise seizure time-intervals with a test subject’s prior seizure intervals. SVM was able to forecast 50%, 70%, 81%, 84%, and 87% of seizures of unseen subjects within 0, 1, 2, 3 to 4 d of mean absolute forecasting error, respectively. The subject-wise performances show that patients with more frequent seizures were generally better predicted. Significance. ML models can leverage non-random patterns within self-reported seizure diaries to forecast future seizures. While diary-based seizure forecasting alone is only one of many aspects of clinical care of patients with epilepsy, studying the level of predictability across seizures and patients paves the path towards a better understanding of predictable vs unpredictable seizures on individualized and population-wise bases.

Local-scale habitat configuration makes a niche for wildlife encroaching into an urban landscape: grubbing sites of wild boar Sus scrofa in a city matrix

Urban environments may offer certain species diverse and abundant food resources of natural and anthropogenic origin. However, the local-scale configuration of habitats and urban infrastructure may influence foraging decisions regardless of the availability of food. In recent years, the expansion of wild boar Sus scrofa into areas significantly transformed by humans has been observed in many parts of its range. Grubbing (rooting) is a major foraging mode of the species, during which disturbance of the upper soil layers enables these animals to find and consume food items. However, the factors that determine the selection of grubbing sites in the urban landscape, where the balance between food availability and the avoidance of humans may influence foraging decisions, are not known. Our aim was to identify local-scale factors that influence grubbing site selection and the size of grubbed patches in an urban landscape. The characteristics of 108 wild boar grubbing sites in the city of Kraków (Poland) were compared to randomly selected control sites. The probable presence of a grubbing site was positively correlated with the proportion of meadows and fallow land in the vicinity and with increases in both canopy cover and distance to pavements. The size of a grubbed patch was positively correlated with the percentage of meadows in the vicinity, increasing distance to buildings and decreasing distance to pavements. We found a non-random pattern of grubbing sites in the urban landscape and indicated that the local-scale configuration of vegetation and urban infrastructure contribute to foraging site selection by wild boar. Our study highlights that the encroachment of wildlife into the urban landscape is a complex process, driven by both resource availability and the avoidance of human-related disturbances.

Biotechnologically produced chitosans with nonrandom acetylation patterns differ from conventional chitosans in properties and activities

Chitosans are versatile biopolymers with multiple biological activities and potential applications. They are linear copolymers of glucosamine and N-acetylglucosamine defined by their degree of polymerisation (DP), fraction of acetylation (FA), and pattern of acetylation (PA). Technical chitosans produced chemically from chitin possess defined DP and FA but random PA, while enzymatically produced natural chitosans probably have non-random PA. This natural process has not been replicated using biotechnology because chitin de-N-acetylases do not efficiently deacetylate crystalline chitin. Here, we show that such enzymes can partially N-acetylate fully deacetylated chitosan in the presence of excess acetate, yielding chitosans with FA up to 0.7 and an enzyme-dependent non-random PA. The biotech chitosans differ from technical chitosans both in terms of physicochemical and nanoscale solution properties and biological activities. As with synthetic block co-polymers, controlling the distribution of building blocks within the biopolymer chain will open a new dimension of chitosan research and exploitation.

Determinants of resource use in lizard assemblages from the semiarid Caatinga, Brazil

AbstractNonsessile animals could partition the use of resources in different axes, reducing the effects of competition and allowing coexistence. Here, we investigated the spatial and trophic niche dimensions in four lizard assemblages in the Neotropical semiarid Caatinga to investigate the determinants of resource use and the extent to which lizards partition their niches. We sampled each lizard assemblage once, for 10 days, in the dry season of 2017 and 2018. In two lizard assemblages, we detected nonrandom niche overlap patterns that were higher or lower than expected by chance. The high niche overlap patterns suggest that either there is intense current competition for available microhabitats or an abundance of microhabitats. The lower niche overlap may be influenced by the presence of species adapted to sandy habitats (psammophilous), suggesting that spatial partitioning detected has historical basis, which is supported by the pPCA results and by the lack of patterns in the realized niche distribution of species across niche space. We detected trophic niche partitioning in three lizard assemblages. In one assemblage, we discovered random spatial and trophic niche overlap patterns, revealing that competition is not a determining factor in the structure of that assemblage. In fact, phylogenetic effects were predominantly the main determinants of resource use in the four studied lizard assemblages. Arid and semiarid habitats cover about one third of land surface of the world. Comparisons between our findings and those from other regions of the world may aid identify general trends in the lizard ecology of dry environments.

A phytoplankton time series in the Northwestern Adriatic Sea: Structure and dynamics of the assemblages in a coastal ecosystem

Phytoplankton assemblage structure was analyzed based on time series data (2008–2019) together with environmental variables in two coastal sites in the Northwestern Adriatic Sea. The main component of phytoplankton assemblage was the diatom group. Distinct seasonal and inter annual variations in the presence of taxa were observed within the phytoplankton assemblage over the study period. Mainly four taxa showed a non-random pattern in the binary time series, such as three diatoms Skeletonema marinoi, Thalassionema nitzschioides and Dactyliosolen fragilissimus, and undetermined Dinophyceae. S. marinoi was more frequent in winter and early spring, whereas T. nitzschioides showed an opposite pattern, being more frequent in late spring and summer. In both cases, deviation from randomness was caused by a clear and almost stationary annual cycle. On the contrary, deviation from randomness depended on the long-term trend of D. fragilissimus time series, as this diatom showed an increasing frequency of occurrence since 2016. A clear phytoplankton assemblage structure affected by seasonal and environmental factors was observed. This was very evident for representative specie (i.e., S. marinoi associated with colder and rich nutrient waters or Heterocapsa niei and T. nitzschioides associated with high temperature and low nutrient conditions) and other species associated with various environmental parameters. Furthermore, the analysis of the association among phytoplankton taxa showed a partial and varied pattern. Our results highlight that phytoplankton time series showed changes in assemblage structure exhibiting a regular 12-month period affected by environmental factors. The long time series observations are important to understand the phytoplankton assemblage structure in relation to environmental changes and human pressures, crucial to achieving the Good Environmental Status in compliance to environmental directives.

Connecting sequence features within the disordered C-terminal linker of Bacillus subtilis FtsZ to functions and bacterial cell division

Intrinsically disordered regions (IDRs) can function as autoregulators of folded enzymes to which they are tethered. One example is the bacterial cell division protein FtsZ. This includes a folded core and a C-terminal tail (CTT) that encompasses a poorly conserved, disordered C-terminal linker (CTL) and a well-conserved 17-residue C-terminal peptide (CT17). Sites for GTPase activity of FtsZs are formed at the interface between GTP binding sites and T7 loops on cores of adjacent subunits within dimers. Here, we explore the basis of autoregulatory functions of the CTT in Bacillus subtilis FtsZ (Bs-FtsZ). Molecular simulations show that the CT17 of Bs-FtsZ makes statistically significant CTL-mediated contacts with the T7 loop. Statistical coupling analysis of more than 1,000 sequences from FtsZ orthologs reveals clear covariation of the T7 loop and the CT17 with most of the core domain, whereas the CTL is under independent selection. Despite this, we discover the conservation of nonrandom sequence patterns within CTLs across orthologs. To test how the nonrandom patterns of CTLs mediate CTT-core interactions and modulate FtsZ functionalities, we designed Bs-FtsZ variants by altering the patterning of oppositely charged residues within the CTL. Such alterations disrupt the core-CTT interactions, lead to anomalous assembly and inefficient GTP hydrolysis invitro and protein degradation, aberrant assembly, and disruption of cell division invivo. Our findings suggest that viable CTLs in FtsZs are likely to be IDRs that encompass nonrandom, functionally relevant sequence patterns that also preserve three-way covariation of the CT17, the T7 loop, and core domain.

Spiking burstiness and working memory in the human medial temporal lobe.

Persistent activity has commonly been considered to be a hallmark of working memory (WM). Recent evidence indicates that neuronal discharges in the medial temporal lobe (MTL) are compatible with WM neural patterns observed in cortical areas. However, the characterization of this activity rarely consists of measurements other than firing rates of single neurons. Moreover, a varied repertoire of firing dynamics has been reported in the MTL regions, which motivate the more detailed examination of the relationships between WM processes and discharge patterns undertaken here. Specifically, we investigate' at different resolution levels, firing irregularities in electrode recordings from the hippocampus, amygdala, and the entorhinal cortex of epileptic patients during a WM task. We show that some types of (ir)regularities predict response times of the patients depending on the trial periods under consideration. Prominent burst activity at the population level is observed in the amygdala and entorhinal cortex during memory retrieval. In general, regular and bursty neurons contribute to the decoding of the memory load, yet they display important differences across the three anatomical areas. Our results suggest that nonrandom (non-Poisson) patterns are relevant for WM, which calls for the development and use of statistics complementary to mere spike counts.

Polymicrobial Foot Infection Patterns Are Common and Associated With Treatment Failure.

That foot infections are predominately polymicrobial has long been recognized, but it is not clear if the various species co-occur randomly or in patterns. We sought nonrandom species co-occurrence patterns that might help better predict prognosis or guide antimicrobial selection. We analyzed tissue (bone, skin, and other soft tissue), fluid, and swab specimens collected from initial foot infection episodes during a 10-year period using a hospital registry. Nonrandom co-occurrence of microbial species was identified using simple pairwise co-occurrence rates adjusted for multiple comparisons, Markov and conditional random fields, and factor analysis. A historical cohort was used to validate pattern occurrence and identify clinical significance. In total, 156 unique species were identified among the 727 specimens obtained from initial foot infection episodes in 694 patients. Multiple analyses suggested that Staphylococcus aureus is negatively associated with other staphylococci. Another pattern noted was the co-occurrence of alpha-hemolytic Streptococcus, Enterococcus fecalis, Klebsiella, Proteus, Enterobacter, or Escherichia coli, and absence of both Bacteroides and Corynebacterium. Patients in a historical cohort with this latter pattern had significantly higher risk-adjusted rates of treatment failure. Several nonrandom microbial co-occurrence patterns are frequently seen in foot infection specimens. One particular pattern with many Proteobacteria species may denote a higher risk for treatment failure. Staphylococcus aureus rarely co-occurs with other staphylococci.

Functional diversity of afrotropical fish communities across river gradients in the Republic of Congo, west central Africa

Characterizing functional freshwater biodiversity patterns and understanding community determinants can aid in predicting changes and prioritizing specific conservation management actions. Afrotropical freshwater systems support diverse ecological communities, including many taxonomically undescribed species, yet few studies have been undertaken in this region and they remain poorly understood. Here, we use functional trait-based approaches to describe the functional diversity of fish assemblages in the Republic of Congo (west Central Africa) from the headwaters of a large basin (upper basin) to the coastal plains (lower basin). Functional traits were assessed using multivariate ordination, and functional diversity was calculated using functional trait-space occupation. We investigated if fish β diversity is nested regionally and at a basin-scale to understand if species assemblages exhibit non-random or environmental filtering patterns. Trait-environment relationships were modeled to determine the most significant drivers of trait diversity, and functional richness (FRic) was calculated for communities in both basins to identify whether Afrotropical systems conform to expected patterns of biodiversity along a fluvial gradient. Moderate to weak community nestedness and various traits associated with resistance and feeding were significantly correlated with habitat variables in the upper and lower basins respectively. Whilst environmental filtering is an important process of community assembly at basin scale, non-random processes are evident in the upper basin, whereas a high turnover was noted in the lower basin. Trophic traits in larger coastal plain habitats of the lower basin suggest higher trophic diversity is associated with higher spatial heterogeneity and nutrient concentrations. High functional turnover between headwaters and coastal plains suggests different functional strategies in fish assemblages between localities along the fluvial gradient. In contrast to expectations derived from temperate lotic systems, functional richness was comparable across both basinswhich suggests that headwater zones in the region harbor substantial functional diversity, especially when considering upstream catchment size. Functional diversity and environment patterns documented show unique patterns of functional richness that may assist in improving understanding of responses, vulnerabilities and conservation needs in Afrotropical systems.

Investigating trends in process error as a diagnostic for integrated fisheries stock assessments

Integrated stock assessments consist of fitting several sources of catch, abundance, and auxiliary biological information to estimate parameters of equations that describe the population dynamics of fish stocks. Stock assessments are subject to uncertainty, and it is a common practice to characterize uncertainty using alternative hypotheses and assumptions within an ensemble of models to develop scientific advice for fisheries management. In this context, there is the need to assign levels of plausibility to each of the combinations of factors that ultimately reflect the uncertainty on different biological and fishery processes. In this study, we describe and apply a model diagnostic to identify trends in process error in recruitment deviation estimates within ensembles of integrated assessment models of tropical tunas. We demonstrate that assessment model ensembles for tropical tunas contain distinct scenarios with significant trends in process error that are overlooked, with the associated implications for fisheries management. Using the Indian Ocean yellowfin as a case study, we found that trends in recruitment deviates are linked to extreme productivity scenarios which strongly diverged in scale from deterministic models fitted without recruitment deviates. This indicates that when recruitment deviates show an increasing trend, these can compensate for the loss of biomass in periods of high catch beyond the surplus production. In these cases, variation in recruitment is not a random process, but rather takes the function of a compensatory, systematic driver in productivity. Significant trends in recruitment were positively correlated with increased standard deviations and auto-correlation coefficient, non-random residual pattern in fits to abundance indices, and particularly poor performance of the Age-Structured Production Model (ASPM) diagnostic. We suggest that trends in recruitment deviates can be caused by misspecification of the biological parameters used as fixed values in integrated assessment models. The process error diagnostic described here can provide a statistical criterion in support for hypotheses and assumptions when using ensembles of models to develop fisheries management advice.

Piloting and validating the linkage of routine ART and laboratory records in an HIV endemic setting.

ObjectivesIntegrating clinical and laboratory data systems offers opportunities to understand disease aetiology and improve patient outcomes. We developed and piloted a data linkage algorithm to link HIV patient treatment records with routine laboratory service records in an HIV endemic setting in rural South Africa. ApproachWe used data from the South Africa’s National Health Laboratory Service (NHLS) and Three Integrated Electronic Registers (TIER.Net) databases for 17 primary healthcare clinics from uMkhanyakude district, South Africa. The two databases contained data on key demographic variables such as patient first name, surname, date of birth, sex, and health facility, and national ID numbers for a subset of the data. We adapted a probabilistic record linkage algorithm we previously developed for linkage of laboratory results. We trained and validated our algorithm using two approaches: 1) firstly, we constructed a quasi-gold standard based on manual review of potential matches for 1,061 randomly selected patients; 2) secondly, we constructed a quasi-gold standard based on records that contained national ID numbers. We calculated the probabilities that the algorithm could correctly identify a true match (sensitivity) and the probabilities that the match identified by the algorithm was truly a match (positive predictive value) using the two approaches. ResultsBetween 2015 and 2020, 55,077 patients were recorded in the HIV treatment database and 386,577 laboratory tests were recorded in the laboratory service database. The sensitivity and positive predictive value in the manually reviewed data were estimated to be 94.4% and 81.2% respectively. The sensitivity and positive predictive value in the matched individual identifiers were estimated to be 99.6% and 99.7% respectively. ConclusionsRecords can be linked successfully, but estimated performance of record linkage depends on the validation set used. Manually reviewed data contain noise and may underestimate performance, while national ID numbers may overestimate performance due to non-random patterns of missingness.

Monthly variations in species co-occurrence patterns of fishes in a temperate estuary

Co-occurrence patterns of species in spatial and temporal scale can provide insight into how fish species distributions and community structure are determined. Identifying temporal shifts of co-occurrence patterns and the influencing factors is important for biodiversity conservation of fish species. However, the species co-occurrence patterns of fishes in estuary are poorly understood in terms of temporal dynamics, especially monthly changes. The co-occurrence patterns of fish communities and the significant species pairs underlying the patterns observed in different months were examined using null model analysis in the Yellow River estuary. Fish communities displayed nonrandom coexistence patterns and were structured in most months in the estuary. A few significantly aggregated or segregated species pairs were found in different months, even though there was no significant overall pattern. Fish species co-occurrence patterns are variable over months and migratory fish species can contribute obviously to forming significant species pairs and structured patterns in the temperate estuary.

Regulation of male germline transmission patterns by the Trp53-Cdkn1a pathway

SummaryA small number of offspring are born from the numerous sperm generated from spermatogonial stem cells (SSCs). However, little is known regarding the rules and molecular mechanisms that govern germline transmission patterns. Here we report that the Trp53 tumor suppressor gene limits germline genetic diversity via Cdkn1a. Trp53-deficient SSCs outcompeted wild-type (WT) SSCs and produced significantly more progeny after co-transplantation into infertile mice. Lentivirus-mediated transgenerational lineage analysis showed that offspring bearing the same virus integration were repeatedly born in a non-random pattern from WT SSCs. However, SSCs lacking Trp53 or Cdkn1a sired transgenic offspring in random patterns with increased genetic diversity. Apoptosis of KIT+ differentiating germ cells was reduced in Trp53- or Cdkn1a-deficient mice. Reduced CDKN1A expression in Trp53-deficient spermatogonia suggested that Cdkn1a limits genetic diversity by supporting apoptosis of syncytial spermatogonial clones. Therefore, the TRP53-CDKN1A pathway regulates tumorigenesis and the germline transmission pattern.

Assessment of the stream invertebrate -diversity along an elevation gradient using a bidimensional null model analysis.

β‐Diversity, commonly defined as the compositional variation among localities that links local diversity (α‐diversity) and regional diversity (γ‐diversity), can arise from two different ecological phenomena, namely the spatial species turnover (i.e., species replacement) and the nestedness of assemblages (i.e., species loss). However, any assessment that does not account for stochasticity in community assembly could be biased and misinform conservation management. In this study, we aimed to provide a better understanding of the overall ecological phenomena underlying stream β‐diversity along elevation gradients and to contribute to the rich debate on null model approaches to identify nonrandom patterns in the distribution of taxa. Based on presence‐absence data of 78 stream invertebrate families from 309 sites located in the Swiss Alpine region, we analyzed the effect size of nonrandom spatial distribution of stream invertebrates on the β‐diversity and its two components (i.e., turnover and nestedness). We used a modeling framework that allows exploring the complete range of existing algorithms used in null model analysis and assessing how distribution patterns vary according to an array of possible ecological assumptions. Overall, the turnover of stream invertebrates and the nestedness of assemblages were significantly lower and higher, respectively, than the ones expected by chance. This pattern increased with elevation, and the consistent trend observed along the altitudinal gradient, even in the most conservative analysis, strengthened our findings. Our study suggests that deterministic distribution of stream invertebrates in the Swiss Alpine region is significantly driven by differential dispersal capacity and environmental stress gradients. As long as the ecological assumptions for constructing the null models and their implications are acknowledged, we believe that they still represent useful tools to measure the effect size of nonrandom spatial distribution of taxa on β‐diversity.

Evidence of Grammatical Knowledge in Apes: An Analysis of Kanzi's Performance on Reversible Sentences.

Ape language acquisition studies have demonstrated that apes can learn arbitrary mappings between different auditory or visual patterns and concepts, satisfying the definition of symbol use. The extent to which apes understand aspects of grammar is less well accepted. On the production side, several studies have shown that apes sometimes combine two or more symbols together, in non-random patterns. However, this is quite limited compared to human language production. On the comprehension side, much greater abilities have been reported in apes. One of the most famous examples is Kanzi, a bonobo who reportedly responded correctly to a large number of novel commands. However, based on his performance on a small subset of reversible sentences—where the understanding of English syntax was critical—the extent to which he demonstrated grammatical knowledge has been questioned. Using a randomization study it is shown here that his performance actually vastly exceeds random chance, supporting the contention that he does in fact understand word order grammatical rules in English. This of course represents only one aspect of English grammar, and does not suggest he has completely human grammatical abilities. However, it does show that he understands one of the arbitrary grammatical devices used in many languages: The use of word order to code argument relations. It also removes from serious consideration the view that apes lack any kind of grammatical ability. From an evolutionary perspective, Kanzi’s ability is most likely to result from homologous brain circuitry, although this is ultimately an empirical question.

Effects of cavity orientation on nesting success inferred from long-term monitoring of the endangered red-cockaded woodpecker

Animals that create structures often display non-random patterns in the direction of their constructions. This tendency of oriented construction is widely presumed to be an adaptive trait of the constructor’s extended phenotype, but there is little empirical support for this hypothesis. Particularly, for cavity nesting-birds there is a lack of studies examining this issue. In this study of a primary cavity excavator, the endangered red-cockaded woodpecker (Dryobates borealis), we show that cavity entrances exhibited a strong westward bias in all 11 of the populations examined throughout the geographic range of the species in the southeastern United States. This species requires cavities in living pine trees for roosting and nesting that often take many years to complete, resulting in many incomplete excavations on the landscape. We used population monitoring data to show that orientation was stronger among completed cavities than incomplete cavities. There was a significant correlation between latitude and average cavity direction among populations, turning northward with increasing latitude, suggesting adaptation to local conditions. Long-term monitoring data showed that cavity orientation and breeding group size are correlated with egg hatching rates, fledging rates, and the total number of fledglings produced per nest. Our results provide empirical evidence from extensive long-term data that directional orientation in animal constructions is an important feature of the extended animal phenotype and have immediate implications for animal ecology and the conservation of endangered species.

Information evolution in complex networks

Many biological phenomena or social events critically depend on how information evolves in complex networks. However, a general theory to characterize information evolution is yet absent. Consequently, numerous unknowns remain about the mechanisms underlying information evolution. Among these unknowns, a fundamental problem, being a seeming paradox, lies in the coexistence of local randomness, manifested as the stochastic distortion of information content during individual-individual diffusion, and global regularity, illustrated by specific non-random patterns of information content on the network scale. Here, we attempt to formalize information evolution and explain the coexistence of randomness and regularity in complex networks. Applying network dynamics and information theory, we discover that a certain amount of information, determined by the selectivity of networks to the input information, frequently survives from random distortion. Other information will inevitably experience distortion or dissipation, whose speeds are shaped by the diversity of information selectivity in networks. The discovered laws exist irrespective of noise, but noise accounts for disturbing them. We further demonstrate the ubiquity of our discovered laws by analyzing the emergence of neural tuning properties in the primary visual and medial temporal cortices of animal brains and the emergence of extreme opinions in social networks.

Direct evidence supporting Darwin's hypothesis of cross-pollination promoted by sex organ reciprocity.

Summary The floral phenotype plays a main role in the attraction and fit of pollinators. Both perianth traits and the positioning of sex organs can be subjected to natural selection and determine nonrandom mating patterns in populations. In stylar‐polymorphic species, the Darwinian hypothesis predicts increased mating success between individuals with sex organs at equivalent heights (i.e. with higher reciprocity).We used paternity analyses in experimental populations of a stylar‐dimorphic species. By comparing the observed mating patterns with those expected under random mating, we tested the effects of sex organ reciprocity and perianth traits on mating success. We also analysed phenotypic selection on perianth traits through female and male functions.The (dis)similarity of parental perianth traits had no direct effects on the mating patterns. Sex organ reciprocity had a positive effect on mating success. Narrow floral tubes increased this effect in upper sex organs. Perianth traits showed little signs of phenotypic selection. Female and absolute fitness measures resulted in different patterns of phenotypic selection.We provide precise empirical evidence of the Darwinian hypothesis about the functioning of stylar polymorphisms, demonstrating that mating patterns are determined by sex organ reciprocity and only those perianth traits which are critical to pollinator fit.

Influence of bacterial community diversity, functionality, and soil factors on polycyclic aromatic hydrocarbons under various vegetation types in mangrove wetlands

Polycyclic aromatic hydrocarbons (PAHs) are prevalent organic pollutants in coastal ecosystems, particularly in mangrove wetlands. However, it is still largely unclear how PAHs affect the soil bacterial community under various vegetation types in the Greater Bay Area. Here, we selected soil samples from four sites with different vegetation types (native mangrove forest dominated by Kandelia candel, invasive mangrove forest dominated by Sonneratia apetala, unvegetated mudflat, and riverine runoff outlet) in the Qi'ao and Futian Nature Reserves. We investigated the effects of PAHs on soil bacterial community composition and diversity, function, and co-occurrence via 16S rRNA high-throughput sequencing. PAHs obviously reduced soil bacterial community diversity and richness. Based on PICRUSt 2, PAHs demonstrated positive influences on PAHs degradation metabolism related bacterial genes. Meanwhile, we predicted that riverine runoff outlets can potentially degrade PAHs, may donate to sustain healthy mangrove ecosystem. Also, PAHs and total nitrogen (TN) were crucial factors driving the soil bacterial community in Qi'ao sites, whereas in the Futian sites, PAHs and SOC were more important. PAHs, SOC and TN showed negative effects on specific bacteria abundance. Subsequently, environmental factors and PAHs levels influenced the soil bacterial ecological functions community. Co-occurrence network analysis revealed non-random assembly patterns of the bacterial communities. SBR1031 and A4b were the keystone genera and played a crucial role whgich played an irreplaceable role in PAHs degradation in Qi'ao and Futian sites. PAHs inhibited specific microbial activity and metabolism in native mangrove forest, while affects positively to bacterial community in riverine runoff outlet which might profoundly affect the whole soil quality under various vegetation types. Overall, this study might identify existing health problems and provide insights for enhancing protection and utilization management for mangrove ecosystem in the Greater Bay Area.