Colonization Patterns Research Articles

Investigating the Translational Value of Periprosthetic Joint Infection Models to Determine the Risk and Severity of Staphylococcal Biofilms.

With the advent of antibiotic-eluting polymeric materials for targeting recalcitrant infections, using preclinical models to study biofilms are crucial for improving the treatment efficacy in periprosthetic joint infections. The stratification of risk and severity of infections is needed to develop an effective clinical dosing framework with better treatment outcomes. We use in vivo and in vitro implant-associated infection models to demonstrate that methicillin-sensitive and resistant Staphylococcus aureus (MSSA and MRSA) have model-dependent distinct implant and peri-implant tissue colonization patterns. The maturity of biofilms and the location (implant vs tissue) were found to influence the antibiotic susceptibility evolution profiles of MSSA and MRSA, and the models could capture the differing host-microbe interactions in vivo. Gene expression studies revealed the molecular heterogeneity of colonizing bacterial populations. The comparison and stratification of the risk and severity of infection across different preclinical models provided in this study can guide clinical dosing to prevent or treat PJI effectively.

House Sparrow Passer domesticus as an Invasive Bird in Thailand, Natural Dispersion or Introduced Species?

Passer domesticus holds the title of being the most widely distributed bird species globally, originating from Central-East Asia and spreading extensively due to human-mediated activities. While initially established as a native species about 10,000 years ago, their association with human-modified habitats has accelerated their expansion, particularly in urban areas. In Thailand, sightings were initially rare but gradually increased, with the species establishing breeding populations, predominantly in urban and suburban areas. This expansion poses challenges as they compete with native species for resources and nesting sites. This study utilized citizen science data from the eBird platform to investigate the factors influencing the expansion of P. domesticus breeding areas in Thailand. Through occupancy modeling, spatiotemporal patterns of colonization were analyzed, revealing the influence of urbanization, vegetation indices, elevation, and proximity to infrastructure. Results showed a steady increase in territorial occupancy, particularly in urbanized regions, with roads and petrol stations acting as facilitators for dispersal. The study underscores the role of urban expansion in facilitating the spread of P. domesticus, raising concerns about its impact on native bird species and biodiversity in Thailand. Further research is warranted to assess the full extent of its ecological implications and to devise strategies for mitigating its potential adverse effects.

Ecological indicators for restoration success: Development of fish diversity in a large restored floodplain over twelve years

The restoration of rivers and their floodplains is complex, requires substantial financial efforts, intensive stakeholder involvement and long recovery times, making the identification of appropriate ecological indicators for restoration success a key challenge. Herein, one of the largest floodplain restorations along the European Danube was repeatedly assessed over a 12-year period. Changes in the fish community composition in relation to chemical and morphological habitat variables were assessed in all three restored habitat types free-flowing rivers (RS), reconnected oxbows (OS), and small floodplain ponds (FP) which are only temporarily connected to the main stem Danube. Fish species composition of RS, OS, FP and the Danube differed significantly. Species numbers (34 detected in 2022) remained largely constant since the last monitoring in 2013, whereas abundance increased by 15%. Small-bodied target species with short generation times were able to establish populations comprising all size classes shortly after restoration, whilst large-bodied species needed a decade after the restoration for full demographic representation. Highly specialised species such as the rheophilic Chondrostoma nasus used restored RS only during the life stages spawning and juvenile growth. Restoration increased habitat heterogeneity and the initialized hydromorphological processes are still ongoing, supporting the high species diversity. The observed differences in colonization patterns can be explained by species-specific life histories, resulting in diverse short and long-term responses of different fish species and life stages following restoration. Consequently, a comprehensive assessment of restoration success only becomes possible if multiple fish species as ecological indicators are combined in a long-term monitoring.

Deciphering diverse colonization patterns of plastisphere generalists and specialists in greenhouse soils

Deciphering diverse colonization patterns of plastisphere generalists and specialists in greenhouse soils

Temperature and Precipitation Explain Bee Diversity on Flowers Along an Elevation Gradient in the Mexican Transition Zone

Although ecologists have identified the key factors influencing species distribution along elevation gradients, each mountain’s distinct characteristics, including its geology and biotic colonization processes, are often overlooked. The uniqueness of each mountain ecosystem implies that species distribution and the factors affecting them may vary across regions and taxonomic groups. The Mexican Transition Zone (MTZ) in central Mexico is a mountainous region of significant ecological and evolutionary importance, shaped by distinct biotic colonization and distribution patterns across its elevation gradient. However, most research in this region has focused on specific taxa, neglecting the vast diversity within the MTZ. In this study, we investigated the variations in flower-visiting bee diversity along an elevation gradient within the MTZ (10 sampling sites distributed from 4 to 3425 m a.s.l..), focusing on understanding the environmental factors influencing their distribution. Our findings reveal a declining bee diversity with increasing elevation, primarily driven by decreasing temperatures. However, when considering bee abundance, we identified precipitation as the predominant factor influencing bee diversity. Therefore, water and resource availability are critical in shaping bee diversity in this region. Furthermore, as elevation increased, we observed distinct and unique bee communities, highlighting the rarity and uniqueness of highland bee species as integral components of mountain ecosystems.

Biogeographical Origins of Caatinga Squamata Fauna

ABSTRACTAimSeveral lines of evidence have noted that open vegetation biomes in the Neotropics are younger than moist forests, leading us to question which historical processes shaped the current species distribution patterns in these new biome formations. Here we investigate the temporal patterns of speciation and colonisation from surrounding biomes (Amazonia, Atlantic Forest and Cerrado) in the Caatinga historical assembly of squamate species, to understand the role of geomorphological events and climate change in driving its diversification.LocationNeotropics.TaxonSquamata (snakes, lizards and amphisbaenians).MethodsWe used a phylogenetic tree and occurrence data for 459 squamate species distributed throughout four different biomes (Amazonia, Atlantic Forest, Cerrado and Caatinga) to reconstruct ancestral geographic ranges using the R package BioGeoBEARS. We used BAMM to estimate the rates of species diversification.ResultsOur results indicate that the current diversity patterns of squamates in the Caatinga were a result of pervasive faunal exchanges from adjacent biomes since the Paleogene, with similar numbers of dispersal events in each source area. The Neogene period was determinant in the diversification process, leading to the current assembly patterns of this group in the Caatinga.Main ConclusionsThe landscape transformation and climate change that increased aridity in northeastern Brazil probably shaped the diversification of dry‐adapted squamates in the Caatinga, like tropidurid lizards. However, the Pleistocene climatic fluctuations associated with the highly heterogeneous gradients of topography, geology, soils, climatic conditions, and different vegetation physiognomies could have facilitated faunal exchange with their neighbouring forested biomes, explaining the current presence of some typical forested lineages inside the Caatinga domain and help us to clarify the current distribution patterns of squamates in this region.

Mechanisms of rhizosphere plant-microbe interactions: molecular insights into microbial colonization.

The rhizosphere, as the "frontline" of plant life, connects plant roots, rhizosphere microorganisms, and surrounding soil, plays a crucial role in plant growth and health, particularly in sustainable agriculture. Despite the well-established contribution of plant-microbe interactions to plant health, the specific molecular mechanisms remain insufficiently understood. This review aims to summarize the physiological adjustments and signal modulation that both plants and microorganisms undergo within this unique ecological niche to ensure successful colonization. By analyzing key processes such as chemotaxis, root attachment, immune evasion, and biofilm formation, we uncover how plants precisely modulate root exudates to either recruit or repel specific microorganisms, thereby shaping their colonization patterns. These findings provide new insights into the complexity of plant-microbe interactions and suggest potential directions for future research in sustainable agriculture.

Influence of Drugs and Toxins on Decomposition Dynamics: Forensic Implications.

Drug and toxin-related deaths are common worldwide, making it essential to detect the postmortem concentration of various toxic substances at different stages of decomposition in a corpse. Indeed, determining the postmortem interval (PMI) and cause of death in an advanced stage of decomposed corpses has been a significant challenge in forensic investigations. Notably, the presence of drugs or toxins can have a significant impact on the microbial profile, potentially altering the succession of microbial communities and subsequent production of volatile organic compounds (VOCs), which, in turn, affect insect colonization patterns. This review aims to highlight the importance of investigating the interactions between drugs or toxins, microbial succession, VOC profiles, and insect behavior, which can provide valuable insights into forensic investigations as well as the ecological consequences of toxins occurring in decomposition. Overall, the detection of drugs and other toxins at different stages of decomposition can yield more precise forensic evidence, thereby enhancing the accuracy of PMI estimation and determination of the cause of death in decomposed remains.

Broad-scale phenotyping in Arabidopsis reveals varied involvement of RNA interference across diverse plant-microbe interactions.

RNA interference (RNAi) is a crucial mechanism in immunity against infectious microbes through the action of DICER-LIKE (DCL) and ARGONAUTE (AGO) proteins. In the case of the taxonomically diverse fungal pathogen Botrytis cinerea and the oomycete Hyaloperonospora arabidopsidis, plant DCL and AGO proteins have proven roles as negative regulators of immunity, suggesting functional specialization of these proteins. To address this aspect in a broader taxonomic context, we characterized the colonization pattern of an informative set of DCL and AGO loss-of-function mutants in Arabidopsis thaliana upon infection with a panel of pathogenic microbes with different lifestyles, and a fungal mutualist. Our results revealed that, depending on the interacting pathogen, AGO1 acts as a positive or negative regulator of immunity, while AGO4 functions as a positive regulator. Additionally, AGO2 and AGO10 positively modulated the colonization by a fungal mutualist. Therefore, analyzing the role of RNAi across a broader range of plant-microbe interactions has identified previously unknown functions for AGO proteins. For some pathogen interactions, however, all tested mutants exhibited wild-type-like infection phenotypes, suggesting that the roles of AGO and DCL proteins in these interactions may be more complex to elucidate.

Impact of non-invasive ventilation on microbial colonisation patterns in preterm infants: a single-centre study.

The objective of this study is to assess the relationship between non-invasive ventilation (NIV) and the colonisation of oral and nasal microbiota in preterm infants within the neonatal intensive care unit (NICU). A prospective cohort study. The NICU of Zhejiang University Children's Hospital. Patients include preterm infants with a gestational age of 28-35 weeks, enrolled within the first 24 hours of life. Infants were categorised based on respiratory support: NIV, which included nasal continuous positive airway pressure, nasal intermittent positive pressure ventilation or high-flow nasal cannula; and no respiratory support, defined as room air or low-flow nasal cannula at ≤2 L/min. The primary outcome was the colonisation of oral and nasal microbiota at 5 days post birth, measured by colony-forming units per millilitre (CFU/mL), with colonisation defined as bacterial growth >103 CFU/mL. The study included 100 preterm infants, with 50 in each group. Nasal microbial colonisation was observed in 56% (28/50) of the NIV group, significantly higher than the 28% in the no respiratory support group. No significant differences were found in oral colonisation. Adjusted binary logistic regression showed an association between NIV and increased risk of nasal colonisation (adjusted OR=2.91, 95% CI 1.12 to 7.58, p=0.028). NIV in preterm infants was linked to a higher risk of nasal microbial colonisation. This finding suggests the need for further research and consideration of infection control strategies in the NICU.

Can microplastics variability drive the colonization dynamics of periphytic protozoan fauna in marine environments?

In recent years, microplastics have become a global environmental hot topic of concern. To explore the effects of different concentrations of microplastics on colonization dynamics of periphytic protozoan fauna, a 21-day study was conducted in temperature-controlled circulation systems. Periphytic protozoan communities were used as test organisms and exposed to five concentrations of MPs: 0, 1, 5, 25, and 125 mg l−1, identification and enumeration were conducted on days 3, 5, 7, 10, 14 and 21. The results showed that the colonization dynamics were driven by MPs and significantly shifted at concentrations over 5 mg l−1. However, a notable decline in maximum species richness and abundance was observed in the high concentrations of microplastic, along with significant deviations in colonization patterns from the control group (0 mg l−1). Therefore, it is suggested that the colonization dynamics of periphytic protozoa can serve as a bioindicator for assessing microplastic concentrations in marine environments.

Phylogenomics and phylogeographic model testing using convolutional neural networks reveal a history of recent admixture in the Canarian Kleinia neriifolia.

Multiple-island endemics (MIE) are considered ideal natural subjects to study patterns of island colonization that involve recent population-level genetic processes. Kleinia neriifolia is a Canarian MIE widespread across the archipelago, which exhibits a close phylogenetic relationship with species in northwest Africa and at the other side of the Sahara Desert. Here, we used target sequencing with plastid skimming (Hyb-Seq), a dense population-level sampling of K. neriifolia, and representatives of its African-southern Arabian relatives to infer phylogenetic relationships and divergence times at the species and population levels. Using population genetic techniques and machine learning (convolutional neural networks [CNNs]), we reconstructed phylogeographic relationships and patterns of genetic admixture based on a multilocus SNP nuclear dataset. Phylogenomic analysis based on the nuclear dataset identifies the northwestern African Kleinia anteuphorbium as the sister species of K. neriifolia, with divergence starting in the early Pliocene. Divergence from its sister clade, comprising species from the Horn of Africa and southern Arabia, is dated to the arid Messinian period, lending support to the climatic vicariance origin of the Rand Flora. Phylogeographic model testing with CNNs supports an initial colonization of the central island of Tenerife followed by eastward and westward migration across the archipelago, which resulted in the observed east/west phylogeographic split. Subsequent population extinctions linked to aridification events, and recolonization from Tenerife, are proposed to explain the patterns of genetic admixture in the eastern Canary Islands. We demonstrate that CNNs based on SNPs can be used to discriminate among complex scenarios of island migration and colonization.

Microbial Colonization Patterns and Prognostic Factors in Cystic Fibrosis Patients: A Comprehensive Assessment

Background: Cystic fibrosis (CF) is one of the most common autosomal recessive genetic disorders in pediatrics. Due to inadequate clearance of inhaled pathogens in the mucus, these organisms colonize the airways, leading to inflammatory responses. The microorganisms identified in sputum cultures of CF patients are critical for selecting the appropriate antibiotics for treatment. Objectives: The main aim of this study is to identify the microorganisms colonizing the sputum of patients with CF and to assess the prognostic factors influencing these colonizations. Methods: This study included all cases of CF patients referred to the pediatric pulmonology clinics at Mofid Pediatric Hospital between 2017 and 2022. Demographic and clinical history data were obtained from clinical records and face-to-face interviews. Sputum cultures were performed for all patients. The chi-square test was applied to identify significant differences in qualitative variables. For quantitative variables, the One-Way ANOVA and Student's t-test were used to find significant differences for parametric data. Results: A total of 206 patients participated in the study, with a mean age of 9.8 ± 5.42 years. Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA) were the most common microorganisms detected, with prevalence rates of 51.94% and 16.99%, respectively. Common microorganisms were more prevalent among patients with normal or below-normal Body Mass Index (BMI), while unusual microorganisms were more frequent in those with above-normal BMI, indicating a significant relationship between microorganism type and BMI (P-value: 0.014). Additionally, common microorganisms were more prevalent in older patients, with a mean age of 10.30 years (P-value = 0.006). No other variables showed statistical significance. Conclusions: PA and SA were the most prevalent microorganisms in the sputum cultures of CF patients. A significant relationship was observed between microorganism type, BMI, and age of the patients.

Phylogeographic structure of Italian Formica pratensis (Retzius 1783) populations in the framework of the species Eurasian range

AbstractThe phylogeography and demographical history of Italian Formica pratensis populations were examined and compared with the Eurasian-wide dataset available for this species and the other red wood ant species Formica lugubris. Forty-eight workers belonging to eight populations from both Alps and Apennines were analysed sequencing a 1.5-kilobase mitochondrial DNA fragment, including the cytochrome b gene and part of the NADH dehydrogenase subunit 6 gene. A total of 127 sequences were screened, scoring 53 different haplotypes amongst all specimens, with five new haplotypes discovered in the Italian populations. All the Italian haplotypes clustered in a monophyletic clade, underlining a clear phylogeographical separation of this group from the other Eurasian groups and suggesting a glacial separate forest refugia and different post-glacial colonisation patterns. The haplotypes from the Alps and the Apennines showed a high genetic proximity, pointing out an ancient (Pleistocene) wide distribution of this species across all these areas and common ancestral lineages. No shared haplotypes were scored between Northern and Central Apennine populations, but the low inter-population genetic distance indicated similar post-glacial selective processes acting on these groups. The diversity we recorded may be influenced by the actual fragmentation of F. pratensis populations across its entire Eurasian range, and by the limited geographical origin and sample dimension of the dataset analysed. Future studies with a more extensive sampling in the Alps and Eastern Europe are needed to confirm our result.

Colonization profiles of gut microbiota in goat kids from neonatal to weaning period.

Understanding the colonization and change patterns of gut microbiota is pivotal for comprehending host health. As a newly cultured breed, the studies on the gut microbiota of Tianfu goats remain limited. This study aimed to address this gap by analyzing the microbial composition and colonization patterns of fecal samples collected from goat kids from birth to weaning. Fecal samples were collected on days 0, 7, 14, 21, 28, 35, 42, 49, 53, 55, 57, and 64, and the changes and colonization patterns of microorganisms were analyzed through high-throughput 16S rRNA sequencing. The results showed that the abundance of fecal microbiota in goat kids gradually increased over time, followed by a decrease after weaning and stabilization, with reduced individual differences. The colonization of fecal microorganisms mainly presented three different stages: days 0-14, days 21-49, and days 53-64. During the suckling period, the relative abundance of Proteobacteria (72.34%) was the highest, followed by Firmicutes (21.66%). From 21 days old, the microbiota in goat kids gradually to be diverse, with Lachnospiraceae and Ruminococcaceae being dominant. During post-weaning, Ruminococcaceae (30.98-33.34%) was becoming prominence which helpful for cellulose decomposition. LEfSe analyzed three important time points (d0 vs. d7, d7 vs. d14, d49 vs. d53, LDA score > 4 and p < 0.05), 53 microbial communities with stage differences were identified. Functional prediction using PICRUSt revealed that differential microbial communities are mainly related to carbohydrate and amino acid metabolism pathways. Overall, this study addresses the intricate relationship between ages, diets, and microbiota compositions in Tianfu goat kids, and also offering insights into microorganisms-host interactions.

Microbiological profiles in periprosthetic joint infections after total knee arthroplasty: a comparative analysis of diabetic and non-diabetic patients.

The purpose of this study is to conduct a comparative analysis of the microbiological profiles in periprosthetic joint infections (PJIs) after total knee arthroplasty (TKA) between diabetic and non-diabetic patients. The study aims to address what are the variations in microbial colonization and infection patterns between diabetic and non-diabetic patients undergoing total knee arthroplasty. A retrospective analysis of 2,569 culture-positive cases of PJIs post-TKA was conducted, comparing outcomes between diabetic (n = 321) and non-diabetic (n = 2,248) patients. Demographic, clinical, and microbiological data were collected and analyzed using descriptive statistics, chi-squared tests, logistic regression, and other statistical tests. Diabetic patients exhibited distinct microbial colonization patterns, with a higher prevalence of pathogens such as Staphylococcus aureus (p = 0.033), Pseudomonas aeruginosa (p < 0.001), Streptococcus spp. (Streptococcus agalactiae and Streptococcus dysgalactiae; p = 0.010, 0.016 respectively), Candida spp. (p = 0.010), and Corynebacterium spp. (p = 0.024). Additionally, diabetic patients were at increased risk of polymicrobial infections. Comorbidities associated with diabetes, including chronic pulmonary disease, renal insufficiency, and peripheral artery disease, were significantly more prevalent in diabetic patients and further complicated PJI outcomes. This study underscores the importance of tailored perioperative antimicrobial strategies and vigilant infection control measures in diabetic patients undergoing TKA. Understanding the differential microbial profiles and associated comorbidities can inform targeted interventions to mitigate the risk of PJIs and improve outcomes in this high-risk population. Further research is warranted to elucidate the underlying mechanisms and optimize management strategies for diabetic patients undergoing TKA.

Oral Cavity Microbiome Impact on Respiratory Infections Among Children.

The respiratory system, traditionally considered antiseptic, harbors a diverse and dynamic bacterial microbiome. Recent advancements in microbiome research have revealed its significant influence on both innate and adaptive immunity, particularly in the context of respiratory infections in children. This article also provides an overview of the types of bacteria that commonly affect the respiratory system, including Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae. These bacteria are prevalent in pediatric populations and significantly contribute to the development and severity of respiratory tract infections (RTIs). This review aims to evaluate the impact of the oral cavity and upper respiratory microbiome on the susceptibility and severity of respiratory infections in pediatric populations. We specifically focus on how early colonization patterns of bacteria such as Moraxella and Streptococcus contribute to the development of respiratory tract infections in children from birth through adolescence. A thorough literature review was performed, focusing on studies publishing between 2004 and 2023. The review included research exploring the role of the upper respiratory microbiome in pediatric populations, with a specific focus on children aged birth to 18 years. Emphasis was placed on microbial characterization, the modulation of immune responses in respiratory tract infections, and the potential therapeutic applications of microbiome-targeted interventions. The findings suggest that the composition and disruption of the upper respiratory microbiome significantly influence clinical outcomes in children with respiratory infections. Notably, dysbiosis in the microbiome has been linked to increased susceptibility to repeated infections, highlighting the importance of maintaining microbial balance for optimal respiratory health. Understanding the impact of oral cavity and upper respiratory microbiome could lead to improved management and prevention strategies for respiratory infections in children. This review underscores the potential of microbiome modulation, including the use of probiotics as a therapeutic approach to enhance clinical outcomes in pediatric respiratory infections.

Isolation and Plant Growth Promotion Effect of Endophytic Siderophore-Producing Bacteria: A Study on Halophyte Sesuvium portulacastrum.

The objective of the present study was to isolate endophytes from the roots of the halophyte Sesuvium portulacastrum, which is applied for aquatic phytoremediation. From these endophytes, siderophore-producing bacteria were specifically isolated for their potential capacity to promote plant growth. The siderophore production capacity of the isolated bacteria was quantified, and a high-yield siderophore-producing strain was selected for further investigation. A total of 33 endophytic bacteria were successfully isolated and identified using a culturable approach. Of these, 10 siderophore-producing bacteria were identified using the selective agar assay, displaying siderophore unit (SU) values ranging from 11.90% to 80.39%. It is noteworthy that Erwinia sp. QZ-E9 exhibited the highest siderophore production capacity, achieving an SU of 80.39%. A microcosm co-cultivation experiment was conducted with the strain QZ-E9 in iron-deficient conditions (2 μmol/L Fe3⁺). The results demonstrated that strain QZ-E9 significantly enhanced the growth of S. portulacastrum, by increases in both fresh weight (1.41 g) and root length (18.7 cm). Furthermore, fluorescence in situ hybridization (FISH) was utilized to ascertain the colonization pattern of strain QZ-E9 within the plant roots. The analysis demonstrated that strain QZ-E9 exhibited extensive colonization of the epidermal and outer cortical cells of S. portulacastrum roots, as well as the intercellular spaces and vascular tissues. This colonization indicated that Erwinia sp. QZ-E9 plays a crucial role in promoting the growth of S. portulacastrum, presumably through its siderophore-mediated iron acquisition mechanism.

Predicting Fungemia in the ICU: Unveiling the Value of Weekly Fungal Surveillance and Yeast Colonisation Monitoring.

Fungemia remains a major threat in intensive care units (ICUs), with high mortality rates despite advances in diagnostics and treatment. Colonisation by yeasts is an independent risk factor for fungemia; however, its predictive utility requires further research. In this 8-year study, we analysed 38,017 samples from 3206 patients and 171 fungemia episodes as part of a weekly fungal surveillance programme. We evaluated species-specific colonisation patterns, the predictive value of the Colonisation Index (CI) and Corrected Colonisation Index (CCI), and candidemia risks associated with different yeast species and anatomical site colonisation. Our results showed that C. auris, N. glabratus, and C. parapsilosis colonisation increased with longer hospital stays (0.8% to 11.55%, 8.13% to 16.8%, and 1.93% to 5.14%, respectively). The CI and CCI had low discriminatory power (AUROC 67% and 66%). Colonisation by any yeast genera demonstrated high sensitivity (98.32%) and negative predictive value (NPV) (95.90%) but low specificity and positive predictive value (PPV) (23.90% and 6.64%). Tracheal and urine cultures had the highest PPV (15.64% and 12.91%), while inguinal cultures had the highest NPV (98.60%). C. auris (12.32%) and C. parapsilosis (5.5%) were associated with a higher fungemia risk (log-rank < 0.001). These findings support the use of weekly surveillance to better stratify the fungemia risk and optimise antifungal use in ICUs.

Reproductive dysfunction in seawater provides an environmental barrier to the range expansion of the invasive Neogobius melanostomus into the North Sea

Salinity can shape species’ distributions via physiological costs. Understanding how and when these costs occur can help predict colonisation patterns, for example during species invasions. To understand the impacts of high salinity environments on the ongoing expansion of the invasive round goby (Neogobius melanostomus) towards the North Sea, fish from this invasion front were spawned in a common-garden setup at different salinities. Reproductive adults were acclimated to a control (20 PSU) salinity representing the current invasion front conditions, and a North Sea coastal salinity (30 PSU). In these salinities they were sorted into spawning groups, and spawning attempts and egg development was tracked during 1.5 months. The results showed a strong impact of the 30 PSU salinity treatment, with a complete developmental failure of all clutches spawned in this salinity. The failed clutches resulted in a significant increase of egg consumption by the nest-guarding males. In addition, sperm velocity showed a decrease with increasing salinity when tested in both spawning salinities and at an intermediate level. Few differences in adult physiology were found as a consequence of the salinity treatments. These results show that, despite adult acclimation to North Sea coastal conditions, the gametes of N. melanostomus cannot as of now cope with the salinities into which their spread is currently predicted. Though adaptation or transgenerational acclimation might allow for reproduction in salinities higher than the species currently occupy, we suggest current models to incorporate a reproductive limit for N. melanostomus at a salinity of 30 PSU.