bluuebunny/crossref_metadata_2025_split huggingface dataset:
Termite males enhance mating encounters by changing speed according to density
Authors: Mizumoto Nobuaki , Rizo Arturo , Pratt Stephen C. , Chouvenc Thomas 
Published: August 2020

Abstract

Search theory predicts that animals evolve efficient movement patterns to enhance encounter rates with specific targets. The optimal movements vary with the surrounding environments, which may explain the observation that animals often switch their movement patterns depending on conditions. However, the effectiveness of behavioural change during search is rarely evaluated because it is difficult to examine the actual encounter dynamics.

Here we studied how partner‐seeking termites update their search strategies depending on the local densities of potential mates. After a dispersal flight, termites drop their wings and walk to search for a mate; when a female and a male meet, they form a female‐led tandem pair and search for a favourable nesting site. If a pair is separated, they have two search options—reunite with their stray partner, or seek a new partner. We hypothesized that the density of individuals affects separation–reunion dynamics and thus the optimal search strategy.

We observed the searching process across different densities and found that termite pairs were often separated but obtained a new partner quickly at high mate density. After separation, while females consistently slowed down, males increased their speed according to the density. Under high mate density, separated males obtained a partner earlier than females, who do not change movement with density.

Our data‐based simulations confirmed that the observed behavioural change by males contributes to enhancing encounters. Males at very low mate densities did best to move slowly and thereby reduce the risk of missing their stray partner, who is the only available mate. On the other hand, males that experienced high mate densities did better in mating encounters by moving fast because the risk of isolation is low, and they must compete with other males to find a partner.

These results demonstrate that termite males adaptively update their search strategy depending on conditions. Understanding the encounter dynamics experienced by animals is key to connecting the empirical work to the idealized search processes of theoretical studies.
Spatiotemporal variation in disturbance impacts derived from simultaneous tracking of aircraft and shorebirds
Authors: van der Kolk Henk‐Jan , Allen Andrew M. , Ens Bruno J. , Oosterbeek Kees , Jongejans Eelke , van de Pol Martijn 
Published: August 2020

Abstract

Assessing the impacts of disturbance over large areas and long time periods is crucial for nature management, but also challenging since impacts depend on both wildlife responses to disturbance and on the spatiotemporal distribution of disturbance sources. Combined tracking of animals and disturbance sources enables quantification of wildlife responses as a function of the distance to a disturbance source. We provide a framework to derive such distance–response curves and combine those with disturbance source presence data to quantify energetic costs of disturbance at a landscape scale.

We tracked 90 Eurasian Oystercatchers Haematopus ostralegus and all aircraft in a military training area in the Dutch Wadden Sea. We quantified distance–response curves estimating flight probability and additional displacement for five types of aircraft activities, by comparing bird movement prior to aircraft presence with movement during aircraft presence. We then used the distance–response curves to map mean and variation in additional daily energy expenditure due to cumulative aircraft disturbance across the landscape for a 700‐day period.

Flight probability and displacement responses differed strongly among aircraft activities and decreased from transport aeroplanes, through bombing jets, helicopters, jets to small civil aeroplanes. Since the most disturbing aircraft activities were also the rarest ones, mean additional daily energy expenditure did not exceed 0.25%. However, days with substantial (>1%) additional expenditure occurred between 0.1% and 3.7% of all days across high‐tide roosts in the tidal basin. Notably, expenditure particularly spiked on days with transport aeroplane activity (up to 8.5%).

Synthesis and applications. We quantified cumulative energetic flight costs due to aircraft disturbance and found that these were low and unlikely to impact survival of oystercatchers in our study area. Our results provide evidence that the legal minimum flight height of 450 m for small civil aeroplanes effectively limits the disturbance of oystercatchers. Mitigation should focus on limiting the number of days when disturbance has a high impact by reducing rare but highly disturbing activities, especially transport aeroplanes. Our approach can be applied to other species and disturbance sources that are automatically tracked, for example boats and walkers, ultimately to quantify the entire anthropogenic disturbance landscape.
A multi‐state occupancy modelling framework for robust estimation of disease prevalence in multi‐tissue disease systems
Authors: Chaudhary Vratika , Wisely Samantha M. , Hernández Felipe A. , Hines James E. , Nichols James D. , Oli Madan K. 
Published: August 2020

Abstract

Given the public health, economic and conservation implications of zoonotic diseases, their effective surveillance is of paramount importance. The traditional approach to estimating pathogen prevalence as the proportion of infected individuals in the population is biased because it fails to account for imperfect detection. A statistically robust way to reduce bias in prevalence estimates is to obtain repeated samples (or sample many tissues in multi‐tissue disease systems) and to apply statistical methods that account for imperfect detection and permit the interdependence of the infection process across multiple tissues.

We developed a multi‐state occupancy modelling framework which considers two scenarios about the infection process, one where no assumptions about the dependencies among the tissues are made (general), and another where dependence among tissues is not permitted (constrained).

We applied this framework to pseudorabies virus (PrV) DNA detection data obtained from whole blood; and oral, nasal and genital mucosa of 510 feral swine Sus scrofa during the years 2014–2016 in Florida, USA.

The constrained model was better supported by data. PrV prevalence estimates varied among tissues and were higher than the naïve estimates, ranging from to 0.06 (CI: 0.02–0.14) in genital to 0.54 (CI: 0.14 ‐ 0.82) in nasal tissue. Probability of PrV detection ranged from 0.11 (CI: 0.06–0.18) in nasal to 0.51 (CI: 0.21–0.81) in genital tissue.

PrV prevalence was not affected by the age or sex of the animal or the year of sampling, but prevalence increased as drought severity increased.

The conditional probability of detecting PrV given infection in at least one tissue type within an individual was highest for nasal tissue, suggesting that nasal is the best tissue to sample for PrV surveillance if only one tissue can be sampled, at least for systems with tissue‐specific prevalence and detection probabilities similar to ours.

Synthesis and applications. We focused on inferences about pathogen prevalence in multi‐tissue disease systems, dealing with both nondetection and potential dependencies among tissues in infection status. We found strong evidence of variation in both prevalence and detection probabilities among tissues. Our results emphasize the importance of sampling multiple tissues and of applying inference methods that account for imperfect detection in the surveillance of systemic diseases. The multi‐state modelling framework is broadly applicable to the surveillance of pathogens that infect multiple tissues and can be used even when the infection status of the pathogen in one tissue may depend on the infection status of the pathogen in other tissue(s).
Functional groups of wild bees respond differently to faba bean Vicia faba L. cultivation at landscape scale
Authors: Beyer Nicole , Gabriel Doreen , Kirsch Felix , Schulz‐Kesting Katharina , Dauber Jens , Westphal Catrin 
Published: August 2020

Abstract

Concerns about insect declines are growing and the provisioning of ecosystem services like pollination may be threatened. To safeguard biodiversity, greening measures were introduced within the reform of the EU's Common Agricultural Policy. One measure commonly applied by farmers is the cultivation of nitrogen fixing crops. Although underlying studies are largely missing, this measure is criticized as providing no significant biodiversity benefit.

Using a landscape‐scale approach, we selected 30 paired study landscapes (1 km × 1 km) in Germany, that is, 15 study landscapes with faba bean (FB) fields (Vicia faba L.) and 15 without any grain legumes. Flower‐visiting wild bees were recorded with transect walks at the field margins of different crops using a stratified sampling approach. We analysed the effect of FB cultivation and landscape composition on the abundance and species richness of wild bees as well as on the functional composition of the bee communities.

Bumblebee densities (Bombus spp. Latreille) were more than twice as high in FB compared to control landscapes after the flowering of the beans. Non‐Bombus wild bee densities, however, were not affected by FB cultivation, but were enhanced by increasing amounts of semi‐natural habitats (SNH).

After the beans' blooming had ceased, FB landscapes had a higher proportion of wild bees collecting pollen from Fabaceae than control landscapes. The community‐weighted means for bee size, measured as intertegular distance, were not affected by FB cultivation, but we found smaller species and species with shorter tongues with an increasing percentage of SNH.

Synthesis and applications. The cultivation of faba bean Vicia faba L. strongly increased bumblebee densities throughout the season. This indicates that also on‐field greening measures can support biodiversity. Nevertheless, since only functional groups adapted to faba bean benefit, measures to promote semi‐natural habitats in agricultural landscapes need to be implemented. We conclude that the combination of on‐ and off‐field measures is essential to maintain farmland biodiversity and the Common Agricultural Policy should furthermore promote both.
Wildfire alters the disturbance impacts of an emerging forest disease via changes to host occurrence and demographic structure
Authors: Simler‐Williamson Allison B. , Metz Margaret R. , Frangioso Kerri M. , Rizzo David M. 
Published: August 2020

Abstract

Anthropogenic activities have altered historical disturbance regimes, and understanding the mechanisms by which these shifting perturbations interact is essential to predicting where they may erode ecosystem resilience. Emerging infectious plant diseases, caused by human translocation of nonnative pathogens, can generate ecologically damaging forms of novel biotic disturbance. Further, abiotic disturbances, such as wildfire, may influence the severity and extent of disease‐related perturbations via their effects on the occurrence of hosts, pathogens and microclimates; however, these interactions have rarely been examined.

The disease ‘sudden oak death’ (SOD), associated with the introduced pathogen Phytophthora ramorum, causes acute, landscape‐scale tree mortality in California's fire‐prone coastal forests. Here, we examined interactions between wildfire and the biotic disturbance impacts of this emerging infectious disease. Leveraging long‐term datasets that describe wildfire occurrence and P. ramorum dynamics across the Big Sur region, we modelled the influence of recent and historical fires on epidemiological parameters, including pathogen presence, infestation intensity, reinvasion, and host mortality.

Past wildfire altered disease dynamics and reduced SOD‐related mortality, indicating a negative interaction between these abiotic and biotic disturbances. Frequently burned forests were less likely to be invaded by P. ramorum, had lower incidence of host infection, and exhibited decreased disease‐related biotic disturbance, which was associated with reduced occurrence and density of epidemiologically significant hosts. Following a recent wildfire, survival of mature bay laurel, a key sporulating host, was the primary driver of P. ramorum infestation and reinvasion, but younger, rapidly regenerating host vegetation capable of sporulation did not measurably influence disease dynamics. Notably, the effect of P. ramorum infection on host mortality was reduced in recently burned areas, indicating that the loss of tall, mature host canopies may temporarily dampen pathogen transmission and ‘release’ susceptible species from significant inoculum pressure.

Synthesis. Cumulatively, our findings indicate that fire history has contributed to heterogeneous patterns of biotic disturbance and disease‐related decline across this landscape, via changes to the both the occurrence of available hosts and the demography of epidemiologically important host populations. These results highlight that human‐altered abiotic disturbances may play a foundational role in structuring infectious disease dynamics, contributing to future outbreak emergence and driving biotic disturbance regimes.
Addition of nitrogen to canopy versus understorey has different effects on leaf traits of understorey plants in a subtropical evergreen broad‐leaved forest
Authors: Tang Songbo , Zhang Lingling , Lambers Hans , Ren Wendan , Lu Xiaofei , Hou Enqing , Fu Shenglei , Kuang Yuanwen 
Published: August 2020

Abstract

Atmospheric nitrogen (N) deposition has substantial effects on forest ecosystems. The effects of N deposition on understorey plants have been simulated by spraying N on the forest floor. Such understorey addition of N (UAN) might simulate atmospheric N deposition in a biased manner, because it bypasses the canopy.

We compared the effects of UAN and canopy addition of N (CAN) at 0, 25 and 50 kg N ha−1 year–1 on SLA, leaf construction costs (CC), concentrations of leaf carbon ([C]), nitrogen ([N]), phosphorus ([P]), minerals ([Mineral]), nitrate ([]), lignin ([Lignin]), lipids ([Lipid]), organic acids ([OA]), soluble phenolics ([SP]), total non‐structural carbohydrates ([TNC]) and total structural carbohydrates ([TSC]) in six dominant understorey species in a subtropical evergreen forest after 5 years of N treatments.

We found that leaf CC, [C], [Lignin], [OA], [TNC] and [TSC] were significantly affected by N addition approach and rate, but leaf [P] and [Lipid] were affected by N addition approach and N addition rate respectively; leaf CC, [C], [P], [OA] and [TNC] were significantly lower under UAN than under CAN, but leaf [TSC] and [Lignin] were significantly higher and lower, respectively, under UAN than under CAN at 50 kg N ha−1 year–1; the decline of leaf [C] and [Lignin] contributed to the significantly lower leaf CC under UAN than under CAN.

Synthesis. We show that canopy and understorey N addition exerted significantly different effects on leaf traits of understorey plants. The results indicate that understorey plants in subtropical forest respond differently to UAN from those to atmospheric deposition of N. Further studies are warranted to evaluate the unbiased ecological processes and functions of forest ecosystem responding to atmospheric N deposition via both CAN and UAN experiments over a longer term.
Sex and Race Biases in Allocation of Advanced Heart Failure Therapies
Authors: Breathett K. , Yee E. , Pool N. , Hebdon M. , Crist J. , Yee R. , Knapp S. , Solola S. , Luy L. , Herrera‐Theut K. , Zabala L. , Stone J. , McEwen M. , Calhoun E. , Sweitzer N. 
Published: August 2020

Research ObjectiveRacial bias influences allocation of advanced heart failure therapies, heart transplants, and ventricular assist devices (VAD). It is unknown whether sex and racial biases influence the allocation of advanced therapies among women. The objective is to determine whether the intersection of patient sex and race influences clinicians' decision making during the allocation of advanced heart failure therapies.Study DesignParticipants were randomized to clinical vignettes which varied by patient race (23 African American, 23 White) and sex (40 women, 6 men), with purposeful target of women vignettes in order to compare with prior studies. Participants were interviewed about their decision making process using the think‐aloud technique and provided supplemental surveys. Interviews were analyzed using grounded theory methodology, and surveys were analyzed with t tests.Population StudiedU.S. members of an international heart transplant organization.Principal FindingsAllocation differences centered upon five themes. First, clinicians’ critiqued the appearance of the women more harshly than men as overall impressions. Second, the African American man was perceived as sicker than other racial/sex groups. Third, there was more concern regarding appropriateness of prior care of the African American woman compared to the White woman. Fourth, there were greater concerns about adequacy of social support of the women. Children were perceived as liabilities for women, particularly the African American woman. Family dynamics and finances were greater concerns for the African American woman. Spouses were deemed inadequate support for women. Last, participants recommended VAD over transplant for all racial/sex groups. Surveys demonstrated similar final recommendations.ConclusionsDespite identical clinical vignettes, the decision making process varied by patient sex and race. Women patients were judged more harshly by their appearance and adequacy of social support, particularly the African American woman.Implications for Policy or PracticeFuture research should investigate whether objective assessments of social support lead to equity in advanced therapy allocation.Primary Funding SourceNational Institutes of Health.
A thorough study of a Paratylenchus sp. in glasshouse‐grown lettuce: Characterisation, population dynamics, host plants and damage threshold as keys to its integrated management
Authors: Claerbout Jolien , Vandevelde Isabel , Venneman Sofie , Kigozi Andrew , de Sutter Nancy , Neukermans Jenny , Bleyaert Peter , Bert Wim , Höfte Monica , Viaene Nicole 
Published: August 2020

AbstractIn glasshouses practising monoculture of butterhead lettuce in Belgium, high densities of pin nematodes (Paratylenchus spp.) are frequently associated with reduced plant growth. Growers currently apply chemical soil disinfestation measures to manage this problem, although stricter phytosanitary regulations are forcing a shift towards integrated management. Efficient implementation of such management requires knowledge about the factors influencing nematode population dynamics, and the damage threshold for lettuce. The nematode populations in five Belgian glasshouses were monitored for at least 1 year by frequently soil sampling at 0–30 cm and 30–60 cm depth. An undescribed species of Paratylenchus was identified in all glasshouses based on morphological and molecular features. High nematode densities (>20,000 (100 ml soil)−1) occurred in winter and spring. Chemical soil disinfestation lowered these populations greatly, although up to 14% survived in the deeper soil layer. After soil steaming under negative pressure, no pin nematodes were found. After 2 months of black fallow pin nematode densities were reduced by 50%–76%. Lamb's lettuce, parsley and wild rocket were found to be poor hosts in a pot experiment, while reproduction factors (Pf/Pi) on lettuce cultivars varied between 1 and 3. In three experiments with butterhead lettuce ‘Cosmopolia’ in pots with a series of 9 or 10 densities of Paratylenchus sp. [up to 35,000 (100 ml soil)−1], no damage to lettuce heads was observed. However, root weight and root quality were reduced, and the corresponding damage thresholds were rather low [1,754 and 362 Paratylenchus sp. (100 ml soil)−1, respectively]. Management strategies such as crop rotation, soil disinfestation or fallow are recommended to avoid pin nematode population build‐up.
RAGE and TLR4 differentially regulate airway hyperresponsiveness: Implications for COPD
Authors: Allam Venkata Sita Rama Raju , Faiz Alen , Lam Maggie , Rathnayake Senani N. H. , Ditz Benedikt , Pouwels Simon D. , Brandsma Corry‐Anke , Timens Wim , Hiemstra Pieter S. , Tew Gaik W. , Neighbors Margaret , Grimbaldeston Michele , van den Berge Maarten , Donnelly Sheila , Phipps Simon , Bourke Jane E. , Sukkar Maria B. 
Published: August 2020

AbstractBackgroundThe receptor for advanced glycation end products (RAGE) and Toll‐like receptor 4 (TLR4) is implicated in COPD. Although these receptors share common ligands and signalling pathways, it is not known whether they act in concert to drive pathological processes in COPD. We examined the impact of RAGE and/or TLR4 gene deficiency in a mouse model of COPD and also determined whether expression of these receptors correlates with airway neutrophilia and airway hyperresponsiveness (AHR) in COPD patients.MethodsWe measured airway inflammation and AHR in wild‐type, RAGE−/−, TLR4−/− and TLR4−/−RAGE−/− mice following acute exposure to cigarette smoke (CS). We also examined the impact of smoking status on AGER (encodes RAGE) and TLR4 bronchial gene expression in patients with and without COPD. Finally, we determined whether expression of these receptors correlates with airway neutrophilia and AHR in COPD patients.ResultsRAGE−/− mice were protected against CS‐induced neutrophilia and AHR. In contrast, TLR4−/− mice were not protected against CS‐induced neutrophilia and had more severe CS‐induced AHR. TLR4−/−RAGE−/− mice were not protected against CS‐induced neutrophilia but were partially protected against CS‐induced mediator release and AHR. Current smoking was associated with significantly lower AGER and TLR4 expression irrespective of COPD status, possibly reflecting negative feedback regulation. However, consistent with preclinical findings, AGER expression correlated with higher sputum neutrophil counts and more severe AHR in COPD patients. TLR4 expression did not correlate with neutrophilic inflammation or AHR.ConclusionsInhibition of RAGE but not TLR4 signalling may protect against airway neutrophilia and AHR in COPD.