Acyl chain selection couples the consumption and synthesis of phosphoinositides.

Phosphoinositides (PIPn) in mammalian tissues are enriched in the stearoyl/arachidonoyl acyl chain species ("C38:4"), but its functional significance is unclear. We have used metabolic tracers (isotopologues of inositol, glucose and water) to study PIPn synthesis in cell lines in which this enrichment is preserved to differing relative extents. We show that PIs synthesised from glucose are initially enriched in shorter/more saturated acyl chains, but then rapidly remodelled towards the C38:4 species. PIs are also synthesised by a distinct 're-cycling pathway', which utilises existing precursors and exhibits substantial selectivity for the synthesis of C38:4-PA and -PI. This re-cycling pathway is rapidly stimulated during receptor activation of phospholipase-C, both allowing the retention of the C38:4 backbone and the close coupling of PIPn consumption to its resynthesis, thus maintaining pool sizes. These results suggest that one property of the specific acyl chain composition of PIPn is that of a molecular code, to facilitate 'metabolic channelling' from PIP2 to PI via pools of intermediates (DG, PA and CDP-DG) common to other lipid metabolic pathways.

CDS2 expression regulates de novo phosphatidic acid synthesis.

CDS enzymes (CDS1 and 2 in mammals) convert phosphatidic acid (PA) to CDP-DG, an essential intermediate in the de novo synthesis of PI. Genetic deletion of CDS2 in primary mouse macrophages resulted in only modest changes in the steady-state levels of major phospholipid species, including PI, but substantial increases in several species of PA, CDP-DG, DG and TG. Stable isotope labelling experiments employing both 13C6- and 13C6D7-glucose revealed loss of CDS2 resulted in a minimal reduction in the rate of de novo PI synthesis but a substantial increase in the rate of de novo PA synthesis from G3P, derived from DHAP via glycolysis. This increased synthesis of PA provides a potential explanation for normal basal PI synthesis in the face of reduced CDS capacity (via increased provision of substrate to CDS1) and increased synthesis of DG and TG (via increased provision of substrate to LIPINs). However, under conditions of sustained GPCR-stimulation of PLC, CDS2-deficient macrophages were unable to maintain enhanced rates of PI synthesis via the 'PI cycle', leading to a substantial loss of PI. CDS2-deficient macrophages also exhibited significant defects in calcium homeostasis which were unrelated to the activation of PLC and thus probably an indirect effect of increased basal PA. These experiments reveal that an important homeostatic response in mammalian cells to a reduction in CDS capacity is increased de novo synthesis of PA, likely related to maintaining normal levels of PI, and provides a new interpretation of previous work describing pleiotropic effects of CDS2 deletion on lipid metabolism/signalling.

Relationship between trauma, psychological distress and help-seeking among corrective service workers.

BACKGROUND: Corrective service workers (CSWs) are at high risk of post-traumatic stress disorder (PTSD) and other mental health problems. Prevalence rates and help-seeking behaviours are under-researched within this population. AIMS: To assess rates of PTSD and distress, and identify predictors of intention to seek help, among workers at an Australian corrective service agency. METHODS: A cross-sectional online survey was used to collect data on staff demographics, employment, PTSD symptoms and current distress. Participants received a tailored feedback report including referral to relevant mental health services (where applicable) and were asked to indicate their likelihood of seeking help. Prevalence data are reported. Binary logistic regression was used to examine relationships between participant characteristics and help-seeking for those with probable PTSD and/or high psychological distress. RESULTS: Participants (n=1001) were predominantly men (56.8%) with a mean age of 46.72 (SD=11.00). Over half (58.0%) were classified as probable PTSD cases, and one-third (33.0%) were experiencing high psychological distress. Around a third (34.3%) of participants with probable PTSD and/or elevated distress indicated they were likely to seek help. Older age and fewer years of service were associated with increased help-seeking intentions. CONCLUSIONS: CSWs were found to be experiencing probable PTSD at higher rates than reported in previous studies. Relatively few intended to seek help from mental health services, despite being provided with personalised screening and feedback along with access to specialised care. Future research should investigate the potential role of organisational support as a facilitator of help-seeking within this population.

Selective Prevention of Depression in Workers Using a Smartphone App: Randomized Controlled Trial.

BACKGROUND: There is increasing evidence that depression can be prevented; however, universal approaches have had limited success. Appropriate targeting of interventions to at-risk populations has been shown to have potential, but how to selectively determine at-risk individuals remains unclear. Workplace stress is a risk factor for depression and a target for intervention, but few interventions exist to prevent depression among workers at risk due to heightened stress. OBJECTIVE: This trial aimed to evaluate the efficacy of a smartphone-based intervention in reducing the onset of depression and improving related outcomes in workers experiencing at least moderate levels of stress. METHODS: A randomized controlled trial was conducted with participants who were currently employed and reported no clinically significant depression and at least moderate stress. The intervention group (n=1053) were assigned Anchored, a 30-day self-directed smartphone app-based cognitive behavioral- and mindfulness-based intervention. The attention-control group (n=1031) were assigned a psychoeducation website. Assessment was performed via web-based self-report questionnaires at baseline and at 1-, 3-, and 6-month postbaseline time points. The primary outcome was new depression caseness aggregated over the follow-up period. The secondary outcomes included depressive and anxiety symptoms, stress, well-being, resilience, work performance, work-related burnout, and quality of life. Analyses were conducted within an intention-to-treat framework using mixed modeling. RESULTS: There was no significant between-group difference in new depression caseness (z score=0.69; P=.49); however, those in the Anchored arm had significantly greater depressive symptom reduction at 1 month (Cohen d=0.02; P=.049) and 6 months (Cohen d=0.08; P=.03). Anchored participants also showed significantly greater reduction in anxiety symptoms at 1 month (Cohen d=0.07; P=.04) and increased work performance at 1 month (Cohen d=0.07; P=.008) and 6 months (Cohen d=0.13; P=.01), compared with controls. Notably, for Anchored participants completing at least two-thirds of the intervention, there was a significantly lower rate of depression onset (1.1%, 95% CI 0.0%-3.7%) compared with controls (9.0%, 95% CI 6.8%-12.3%) at 1 month (z score=4.50; P<.001). Significant small to medium effect sizes for most secondary outcomes were seen in the highly engaged Anchored users compared with controls, with effects maintained at the 6-month follow-up for depressive symptoms, well-being, stress, and quality of life. CONCLUSIONS: Anchored was associated with a small comparative reduction in depressive symptoms compared with controls, although selective prevention of case-level depression was not observed in the intention-to-treat analysis. When users adequately engaged with the app, significant findings pertaining to depression prevention, overall symptom reduction, and functional improvement were found, compared with controls. There is a need for a greater focus on engagement techniques in future research. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12620000178943; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378592.

Differentiation of immortalized human multi-lineage progenitor to alveolar type 2-like cells: angiotensin-converting enzyme 2 expression and binding of severe acute respiratory syndrome coronavirus 2 spike and spike 1 proteins.

Along with the nasal epithelium, the lung epithelium is a portal of entry for sudden acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and many other respiratory viruses. In the case of SARS-CoV-2, the virus surface spike proteins bind to the angiotensin-converting enzyme 2 (ACE-2) receptor to facilitate entry into the respiratory epithelium. Alveolar type 2 (AT2) cells are committed respiratory progenitor cells responsible for the integrity and regeneration of the respiratory epithelium and production of respiratory surfactant proteins. AT2 cells express high levels of surface ACE-2 and thus are a leading target for primary infection by SARS-CoV-2. This study describes a method for directly differentiating telomerase reverse transcriptase-immortalized human cord blood-derived multi-lineage progenitor cells (MLPCs) to AT2-like cells for the purpose of generating an in vitro cellular platform for viral studies. Differentiation was confirmed with the acquisition of AT2 and absence of alveolar type 1 (AT1) specific markers by confocal microscopy. Expression of the ACE-2 receptor was confirmed by immunofluorescence antibody staining, quantitative reverse transcription polymerase chain reaction and binding of biotinylated SARS-CoV-2 spike and spike 1 proteins. The binding of biotinylated spike proteins was specifically blocked by unlabeled spike proteins and neutralizing antibodies. Additionally, it was demonstrated that the spike protein was internalized after binding to the surface membrane of the cells. The authors defined the culture conditions that enabled AT2-like cells to be repeatedly passaged and cryopreserved without further differentiation to AT1. The authors' method provides a stable and renewable source of AT2 cells for respiratory viral binding, blocking and uptake studies.

Severe infections in neurocritical care.

PURPOSE OF REVIEW: We have highlighted the recent advances in infection in neurocritical care. RECENT FINDINGS: Central nervous system (CNS) infections, including meningitis, encephalitis and pyogenic brain infections represent a significant cause of ICU admissions. We underwent an extensive review of the literature over the last several years in order to summarize the most important points in the diagnosis and treatment of severe infections in neurocritical care. SUMMARY: Acute brain injury triggers an inflammatory response that involves a complex interaction between innate and adaptive immunity, and there are several factors that can be implicated, such as age, genetic predisposition, the degree and mechanism of the injury, systemic and secondary injury and therapeutic interventions. Neuroinflammation is a major contributor to secondary injury. The frequent and challenging presence of fever is a common denominator amongst all neurocritical care patients.

Site-Specific Synthesis of Cysteine-Bridged Glycoproteins via Expressed Protein Glycoligation.

Site-specific glycosylation of a functional recombinant protein thioester is reported. The thioester functionalized protein sfGFP-Y151ThioD, prepared by genetic code expansion, underwent native chemical ligation with the cysteine-conjugated glycans H-Cys-NH-GlcNAc and H-Cys-NH-(GlcNAc)2(Man)3 to give the corresponding cysteine-bridged glycoproteins. The intact glycoproteins, which retained their fluorescence, were characterized by top-down mass spectrometry and gel electrophoresis. The bridging cysteine provided a convenient handle for affinity chromatography purification of the glycoproteins via a removable biotin tag. Given the influence that specific glycoforms can have on a protein's function, the ability to attach a homogeneous glycan to an intact protein in a functional group controlled yet sequon-independent manner could find widespread application. These preliminary results set the stage for development of the expressed protein glycoligation (EPG) concept.

Climate and human water use diminish wetland networks supporting continental waterbird migration.

Migrating waterbirds moving between upper and lower latitudinal breeding and wintering grounds rely on a limited network of endorheic lakes and wetlands when crossing arid continental interiors. Recent drying of global endorheic water stores raises concerns over deteriorating migratory pathways, yet few studies have considered these effects at the scale of continental flyways. Here, we investigate the resiliency of waterbird migration networks across western North America by reconstructing long-term patterns (1984-2018) of terminal lake and wetland surface water area in 26 endorheic watersheds. Findings were partitioned regionally by snowmelt- and monsoon-driven hydrologies and combined with climate and human water-use data to determine their importance in predicting surface water trends. Nonlinear patterns of lake and wetland drying were apparent along latitudinal flyway gradients. Pervasive surface water declines were prevalent in northern snowmelt watersheds (lakes -27%, wetlands -47%) while largely stable in monsoonal watersheds to the south (lakes -13%, wetlands +8%). Monsoonal watersheds represented a smaller proportion of total lake and wetland area, but their distribution and frequency of change within highly arid regions of the continental flyway increased their value to migratory waterbirds. Irrigated agriculture and increasing evaporative demands were the most important drivers of surface water declines. Underlying agricultural and wetland relationships however were more complex. Approximately 7% of irrigated lands linked to flood irrigation and water storage practices supported 61% of all wetland inundation in snowmelt watersheds. In monsoonal watersheds, small earthen dams, meant to capture surface runoff for livestock watering, were a major component of wetland resources (67%) that supported networks of isolated wetlands surrounding endorheic lakes. Ecological trends and human impacts identified herein underscore the importance of assessing flyway-scale change as our model depictions likely reflect new and emerging bottlenecks to continental migration.

ParentWorks: Evaluation of an Online, Father-Inclusive, Universal Parenting Intervention to Reduce Child Conduct Problems.

Evidence-based parenting interventions are effective in reducing conduct problems, yet these interventions have limited reach, and few involve the participation of fathers. This paper describes the outcomes of an open trial of ParentWorks, a universal, online, father-inclusive parenting intervention aiming to decrease childhood behavioural problems and promote positive parenting in mothers and fathers. A total of 388 families (456 individual parents; 36.6% fathers) were included in the study. Mixed model analyses showed significant decreases in child emotional/behavioural problems, dysfunctional parenting, interparental conflict, and parental mental health problems. The baseline severity of child behavioural problems significantly moderated the effects on child outcomes so that children with higher levels of problems benefitted more from the program. Participation of both caregivers in two-parent families, as well as parent sex, did not significantly affect the program outcomes. Results provide initial empirical support for the universal, self-directed, online parenting intervention, in addressing both child behavioural problems and parenting outcomes. Trial registration: ACTRN12616001223426, registered 05/09/2016.

Keeping Parents Involved: Predicting Attrition in a Self-Directed, Online Program for Childhood Conduct Problems.

Positive parenting programs have a strong evidence base for improving parent-child relationships, strengthening families, and reducing childhood behavior disturbances. Their reach is less than optimal however, with only a minority of families in need of help participating. Father involvement is particularly low. Online, self-directed programs have the potential to improve participation rates. This article examines risk factors for dropout/attrition from a free, evidence-based, self-directed, father-inclusive parenting program, Parentworks, which was made available across Australia. Parents (N = 2,967) enrolled in the program and completed preintervention questionnaires. There was a steady and consistent loss of participants through the sequence of core program modules, until a final sample of 218 completed the postintervention questionnaire. A range of demographic and parent and child variables were tested as predictors of 3 subgroups: nonstarters, partial completers, and full completers. Nonstarters (n = 1,625) tended to have older children with fewer behavioral problems and report higher psychopathology and dysfunctional parenting than those who partially (n = 1,124) or fully completed. Contrary to findings from face-to-face research, single parents had the highest completion rates. Coparticipation of partners and interparental conflict had no impact on completion rates. Fathers participated at relatively high levels. Results show that parents with the greatest need tend to engage with online programs, and online programs may be particularly useful for fathers, single parents, and those in conflicted relationships. Directions for future program design and research are discussed.

Evaluation of 'The Father Effect' Media Campaign to Increase Awareness of, and Participation in, an Online Father-Inclusive Parenting Program.

There is substantial evidence that parenting programs are effective in improving parenting and child mental health outcomes. While there is increasing focus on delivering parenting interventions online to increase their reach and dissemination, fathers are underrepresented in all formats of parenting programs. However, research suggests that father participation is important for intervention effectiveness. This study evaluated the effectiveness of a media campaign for increasing awareness of, and participation in, an online father-inclusive parenting program called 'ParentWorks'. An 8-week campaign was conducted in Australia via social media channels, digital display advertising, digital television, and radio. To assess the impact of the campaign, data were obtained from caregivers registering for ParentWorks during the campaign period (n = 848) and an 8-week comparison period that occurred 3 months later (n = 254). Additionally, a nationally representative sample of 2021 caregivers of children aged 2-16 years completed an online survey. Survey questions asked about exposure to the campaign, registration for participation in ParentWorks, and knowledge of the importance of father participation in parenting programs. Three times as many caregivers registered during the 8-week media campaign compared to the comparison period, and a significantly greater proportion of male caregivers registered in the campaign versus the comparison period. The online survey found that 11% of caregivers reported exposure to the campaign, and significantly more fathers than mothers reported exposure. Results showed that those who were exposed to the campaign were significantly more likely to endorse the importance of father participation in parenting programs, than those not exposed to the campaign. The findings indicate that media campaigns appear to be an effective method of increasing awareness of online parenting programs and enhancing rates of father involvement.

Toward Father-friendly Parenting Interventions: A Qualitative Study.

Levels of father participation in parenting interventions are often very low, yet little is known about the factors which influence father engagement. We aimed to qualitatively explore perceived barriers to, and preferences for, parenting interventions in a community sample of fathers. Forty-one fathers across nine focus groups were interviewed using a semi-structured interview. Data were analysed using inductive thematic analysis. Key barriers to father participation identified included: the perception that interventions are mother-focused; beliefs about gender roles regarding parenting and help-seeking; mothers' role as 'gatekeeper'; lack of knowledge and awareness of parenting interventions; and lack of relevance of interventions. Fathers reported preferences for specific content and intervention features, facilitator characteristics, practical factors, and highlighted the need for father-targeted recruitment and advertising. Many of the barriers and preferences identified are consistent with previous research; however, fathers' beliefs and attitudes around gender roles and help-seeking, as well as the perception that interventions are predominantly mother-focused, may be key barriers for community fathers. Strategies to overcome these barriers and better meet the needs of fathers in promoting and delivering parenting interventions are discussed.

Optimising child outcomes from parenting interventions: fathers' experiences, preferences and barriers to participation.

BACKGROUND: Early childhood interventions can have both immediate and long-term positive effects on cognitive, behavioural, health and education outcomes. Fathers are underrepresented in interventions focusing on the well-being of children. However, father participation may be critical for intervention effectiveness, especially for parenting interventions for child externalising problems. To date, there has been very little research conducted to understand the low rates of father participation and to facilitate the development of interventions to meet the needs of fathers. This study examined fathers' experiences of, and preferences for, parenting interventions as well as perceptions of barriers to participation. It also examined how these factors were associated with child externalising behaviour problems, and explored the predictors of participation in parenting interventions. METHODS: A community sample of 1001 fathers of children aged 2-16 years completed an online survey about experiences with parenting interventions, perceived barriers to participation, the importance of different factors in their decision to attend, and preferred content and delivery methods. They also completed ratings of their child's behaviour using the Strengths and Difficulties Questionnaire. RESULTS: Overall, 15% of fathers had participated in a parenting intervention or treatment for child behaviour, with significantly higher rates of participation for fathers of children with high versus low levels of externalising problems. Fathers rated understanding what is involved in the program and knowing that the facilitator is trained as the two most important factors in their decision to participate. There were several barriers to participation that fathers of children with high-level externalising problems were more likely to endorse, across practical barriers and help-seeking attitudes, compared to fathers of children with low-level externalising problems. Almost two-thirds of fathers of children with high-level externalising behaviour had not participated in a parenting intervention or treatment. The only significant predictors of intervention participation were severity of child externalising behaviour problems and child age. CONCLUSIONS: The findings have important implications for services seeking to increase father engagement and highlight a number of strategies to enhance the promotion and delivery of parenting interventions to fathers. These strategies include more public health messaging about parenting programs and the importance of father participation.

Redox-dependent stability, protonation, and reactivity of cysteine-bound heme proteins.

Cysteine-bound hemes are key components of many enzymes and biological sensors. Protonation (deprotonation) of the Cys ligand often accompanies redox transformations of these centers. To characterize these phenomena, we have engineered a series of Thr78Cys/Lys79Gly/Met80X mutants of yeast cytochrome c (cyt c) in which Cys78 becomes one of the axial ligands to the heme. At neutral pH, the protonation state of the coordinated Cys differs for the ferric and ferrous heme species, with Cys binding as a thiolate and a thiol, respectively. Analysis of redox-dependent stability and alkaline transitions of these model proteins, as well as comparisons to Cys binding studies with the minimalist heme peptide microperoxidase-8, demonstrate that the protein scaffold and solvent interactions play important roles in stabilizing a particular Cys-heme coordination. The increased stability of ferric thiolate compared with ferrous thiol arises mainly from entropic factors. This robust cyt c model system provides access to all four forms of Cys-bound heme, including the ferric thiol. Protein motions control the rates of heme redox reactions, and these effects are amplified at low pH, where the proteins are less stable. Thermodynamic signatures and redox reactivity of the model Cys-bound hemes highlight the critical role of the protein scaffold and its dynamics in modulating redox-linked transitions between thiols and thiolates.

Heme Binding by Corynebacterium diphtheriae HmuT: Function and Heme Environment.

The heme uptake pathway (hmu) of Corynebacterium diphtheriae utilizes multiple proteins to bind and transport heme into the cell. One of these proteins, HmuT, delivers heme to the ABC transporter HmuUV. In this study, the axial ligation of the heme in ferric HmuT is probed by examination of wild-type (WT) HmuT and a series of conserved heme pocket residue mutants, H136A, Y235A, and M292A. Characterization by UV-visible, resonance Raman, and magnetic circular dichroism spectroscopies indicates that H136 and Y235 are the axial ligands in ferric HmuT. Consistent with this assignment of axial ligands, ferric WT and H136A HmuT are difficult to reduce while Y235A is reduced readily in the presence of dithionite. The FeCO Raman shifts in WT, H136A, and Y235A HmuT-CO complexes provide further evidence of the axial ligand assignments. Additionally, these frequencies provide insight into the nonbonding environment of the heme pocket. Ferrous Y235A and the Y235A-CO complex reveal that the imidazole of H136 exists in two forms, one neutral and one with imidazolate character, consistent with a hydrogen bond acceptor on the H136 side of the heme. The ferric fluoride complex of Y235A reveals the presence of at least one hydrogen bond donor on the Y235 side of the heme. Hemoglobin utilization assays showed that the axial Y235 ligand is required for heme uptake in HmuT.

α-Hemoglobin-stabilizing protein (AHSP) perturbs the proximal heme pocket of oxy-α-hemoglobin and weakens the iron-oxygen bond.

α-Hemoglobin (αHb)-stabilizing protein (AHSP) is a molecular chaperone that assists hemoglobin assembly. AHSP induces changes in αHb heme coordination, but how these changes are facilitated by interactions at the αHb·AHSP interface is not well understood. To address this question we have used NMR, x-ray absorption spectroscopy, and ligand binding measurements to probe αHb conformational changes induced by AHSP binding. NMR chemical shift analyses of free CO-αHb and CO-αHb·AHSP indicated that the seven helical elements of the native αHb structure are retained and that the heme Fe(II) remains coordinated to the proximal His-87 side chain. However, chemical shift differences revealed alterations of the F, G, and H helices and the heme pocket of CO-αHb bound to AHSP. Comparisons of iron-ligand geometry using extended x-ray absorption fine structure spectroscopy showed that AHSP binding induces a small 0.03 Å lengthening of the Fe-O2 bond, explaining previous reports that AHSP decreases αHb O2 affinity roughly 4-fold and promotes autooxidation due primarily to a 3-4-fold increase in the rate of O2 dissociation. Pro-30 mutations diminished NMR chemical shift changes in the proximal heme pocket, restored normal O2 dissociation rate and equilibrium constants, and reduced O2-αHb autooxidation rates. Thus, the contacts mediated by Pro-30 in wild-type AHSP promote αHb autooxidation by introducing strain into the proximal heme pocket. As a chaperone, AHSP facilitates rapid assembly of αHb into Hb when ßHb is abundant but diverts αHb to a redox resistant holding state when ßHb is limiting.

Job Loss Due to COVID-19: A Longitudinal Study of Mental Health, Protective and Risk Factors.

The COVID-19 pandemic had a devastating impact on unemployment, which-compounded by the additional stressors associated with the pandemic-had considerable mental health impact. The current study examined the trajectory of mental health amongst those experiencing pandemic-related job loss, alongside the impact of risk and protective factors. Data were obtained from 374 Australian participants who were allocated to a waitlist control arm of a randomised control trial. The outcome variables assessed at baseline and six-month follow-up consisted of depression, anxiety, and suicidality. The assessed risk and protective factors were age, gender, relationship status, education, exercise frequency, COVID-related stress, dispositional resilience, and coping self-efficacy. Re-employment by follow-up was used as a covariate. Overall, there were decreases in depression and anxiety symptoms, and partial evidence of decreased suicidality, demonstrating an apparent capacity for individuals to better cope with their circumstances over time. Demographics and exercise had no effect on changes in mental health. Those with high COVID-related stress, low resilience, and low coping self-efficacy had worse mental health at baseline, although exhibited significantly greater improvements in mental health over time. Obtaining re-employment by follow-up did not predict changes in mental health. The present results offer an optimistic picture of recovery for those experiencing pandemic-related job loss, even for those with the most substantial risk and severity. The likely protective role played by Australian social welfare policies over the course of the study is explored. Stress around one's broader sociocultural or economic circumstances, perceived resilience, and coping self-efficacy are valuable targets for intervention.

Evidence of longitudinal differences in spring migration strategies of an Arctic-nesting goose.

During spring, migratory birds are required to optimally balance energetic costs of migration across heterogeneous landscapes and weather conditions to survive and reproduce successfully. Therefore, an individual's migratory performance may influence reproductive outcomes. Given large-scale changes in land use, climate, and potential carry-over effects, understanding how individuals migrate in relation to breeding outcomes is critical to predicting how future scenarios may affect populations. We used GPS tracking devices on 56 Greater White-fronted Geese (Anser albifrons) during four spring migrations to examine whether migration characteristics influenced breeding propensity and breeding outcome. We found a strong longitudinal difference in arrival to the breeding areas (18 days earlier), pre-nesting duration (90.9% longer), and incubation initiation dates (9 days earlier) between western- and eastern-Arctic breeding regions, with contrasting effects on breeding outcomes, but no migration characteristic strongly influenced breeding outcome. We found that breeding region influenced whether an individual likely pursued a capital or income breeding strategy. Where individuals fell along the capital-income breeding continuum was influenced by longitude, revealing geographic effects of life-history strategy among conspecifics. Factors that govern breeding outcomes likely occur primarily upon arrival to breeding areas or are related to individual quality and previous breeding outcome, and may not be directly tied to migratory decision-making across broad scales.

Human-Induced Range Expansions Result in a Recent Hybrid Zone between Sister Species of Ducks.

Landscapes are consistently under pressure from human-induced ecological change, often resulting in shifting species distributions. For some species, changing the geographical breadth of their niche space results in matching range shifts to regions other than those in which they are formally found. In this study, we employ a population genomics approach to assess potential conservation issues arising from purported range expansions into the south Texas Brush Country of two sister species of ducks: mottled (Anas fulvigula) and Mexican (Anas diazi) ducks. Specifically, despite being non-migratory, both species are increasingly being recorded outside their formal ranges, with the northeastward and westward expansions of Mexican and mottled ducks, respectively, perhaps resulting in secondary contact today. We assessed genetic ancestry using thousands of autosomal loci across the ranges of both species, as well as sampled Mexican- and mottled-like ducks from across overlapping regions of south Texas. First, we confirm that both species are indeed expanding their ranges, with genetically pure Western Gulf Coast mottled ducks confirmed as far west as La Salle county, Texas, while Mexican ducks recorded across Texas counties near the USA-Mexico border. Importantly, the first confirmed Mexican × mottled duck hybrids were found in between these regions, which likely represents a recently established contact zone that is, on average, ~100 km wide. We posit that climate- and land use-associated changes, including coastal habitat degradation coupled with increases in artificial habitats in the interior regions of Texas, are facilitating these range expansions. Consequently, continued monitoring of this recent contact event can serve to understand species' responses in the Anthropocene, but it can also be used to revise operational survey areas for mottled ducks.