Pollen Species Research Articles

Comparing whole-genome shotgun sequencing and DNA metabarcoding approaches for species identification and quantification of pollen species mixtures.

Molecular identification of mixed‐species pollen samples has a range of applications in various fields of research. To date, such molecular identification has primarily been carried out via amplicon sequencing, but whole‐genome shotgun (WGS) sequencing of pollen DNA has potential advantages, including (1) more genetic information per sample and (2) the potential for better quantitative matching. In this study, we tested the performance of WGS sequencing methodology and publicly available reference sequences in identifying species and quantifying their relative abundance in pollen mock communities. Using mock communities previously analyzed with DNA metabarcoding, we sequenced approximately 200Mbp for each sample using Illumina HiSeq and MiSeq. Taxonomic identifications were based on the Kraken k‐mer identification method with reference libraries constructed from full‐genome and short read archive data from the NCBI database. We found WGS to be a reliable method for taxonomic identification of pollen with near 100% identification of species in mixtures but generating higher rates of false positives (reads not identified to the correct taxon at the required taxonomic level) relative to rbcL and ITS2 amplicon sequencing. For quantification of relative species abundance, WGS data provided a stronger correlation between pollen grain proportion and sequence read proportion, but diverged more from a 1:1 relationship, likely due to the higher rate of false positives. Currently, a limitation of WGS‐based pollen identification is the lack of representation of plant diversity in publicly available genome databases. As databases improve and costs drop, we expect that eventually genomics methods will become the methods of choice for species identification and quantification of mixed‐species pollen samples.

Variations in airborne pollen and spores in urban Guangzhou and their relationships with meteorological variables

Airborne pollen causes various types of allergies in humans, and the extent of allergic infection is related to the presence of different types of sporo–pollen and existing meteorological conditions in a certain area. Therefore, an aeropalynological study of 72 airborne samples with a hydrofluoric acid (HF) treatment was conducted in the Haizhu district of Guangzhou, China, in 2016, to identify the temporal variations in airborne sporo–pollen and the relationship between airborne sporo–pollen concentrations and different meteorological variables in Guangzhou, China. Forty-five types of airborne pollen, seven types of airborne spores, and some undetermined sporo–pollen taxa were identified with two separate plant habitats occurring during this period (from January to December 2016): arboreal pollen (tree-based) and non-arboreal pollen (herb, shrub, aquatic, liane, etc.). Furthermore, the daily records of four key meteorological variables (temperature, precipitation, relative humidity, and wind speed) were acquired to distinguish the pollen seasons and correlated with Spearman's rho test to establish a pollen-weather data book with the seasonal variations. The two leading seasons were identified based on pollen abundance: spring and autumn. Among them, the primary dominant sporo–pollen families during the spring season were Poaceae, Pinaceae, Euphorbiaceae, Moraceae, Microlepia sp., and Polypodiaceae. Conversely, Artemisia sp., Asteraceae, Cyperaceae, Poaceae, Alnus sp., Corylus sp., Myrtaceae, and Rosaceae were the dominant pollen species during autumn. However, few pollen grains were identified in January, May–July, and December. The statistical analysis revealed that temperature had both positive and negative correlations with sporo–pollen concentrations. However, precipitation and relative humidity had a strong impact on the sporo–pollen dispersion and exhibited a negative correlation with the sporo–pollen concentrations. The wind speed had a positive but strong correlation with the sporo–pollen concentration during the study period. Some inconsistent results were found due to environmental variations, vegetation type, and climate change around the study area. This study will facilitate the identification of pollen seasons to prevent the occurrence of pollen-related allergies in the Guangzhou city area.

Survey of bee friendly flowering plants and bee-plant interaction in an urban green space in Bengaluru, India

Aim: To study bee friendly plant species, nutritional sources, flowering season, and the dynamic relationship between urban flora and native bee species in a centrally located urban green space in Bengaluru, India. Methodology: Flowers of different plant species visited by bees were observed and recorded from September 2018 to August 2019. Based on the foraging pattern of visiting bees, the plants were classified into nectar or pollen or both nectar and pollen species. The monthly abundance of nutritional resources was estimated based on the floral phenology. Results: A total of 51 plant species, from 25 families, were visited by bees for foraging. Polylectic social bees namely Apis florea and Tetragonula iridipennis, visited 45 and 39 plant species, and two species of solitary bees, namely Amigella cingulate and Xylocopa violacea, visited 26 and 23 plant species, respectively. The urban green landscape was dominated by a variety of ornamental plants (49%) and also included vegetables (17.6%), fruit trees (13.7%), and weeds (19.6%). Plants that served as a source of both nectar and pollen (60.8%) were predominant over those that supplied either nectar alone (24.5%) or pollen alone (13.7%). Moreover, 72% of the species bloomed all the year round, which meant that floral resources were available to bees throughout the year. Interpretation: The study underscores the role of bee friendly floral diversity in the urban green spaces in protection and conservation of bee diversity. Efficient management of urban green spaces can provide dynamic habitat for bee conservation and can prevent the loss of biodiversity.

Lower pollen nutritional quality delays nest building and egg laying in Bombus terrestris audax micro-colonies leading to reduced biomass gain

The performance of Bombus terrestris micro-colonies fed five diets differing in pollen species composition and level of nine essential amino acids (EAA; leucine, lysine, valine, arginine, isoleucine, phenylalanine, threonine, histidine, methionine) was assessed for 37 days by recording total biomass gain, nest building initiation, brood production (eggs, small and large larvae, pupae, drones), nectar, and pollen collection. Stronger colony performance was linked to higher amino acid levels but no consistent differences in biomass gain were recorded between mono- and poly-species diets. Poorest performance occurred in micro-colonies offered pure oilseed rape (OSR) pollen which contained the lowest EAA levels. Reduced micro-colony development (delayed nest initiation and lower brood production) was related to OSR proportion in the diet and lower EAA levels. Results are discussed in relation to selection of plant species in the design of habitats to promote bee populations.

Harnessing the Power of Metabarcoding in the Ecological Interpretation of Plant-Pollinator DNA Data: Strategies and Consequences of Filtering Approaches

Although DNA metabarcoding of pollen mixtures has been increasingly used in the field of pollination biology, methodological and interpretation issues arise due to its high sensitivity. Filtering or maintaining false positives, contaminants, and rare taxa or molecular features could lead to different ecological results. Here, we reviewed how this choice has been addressed in 43 studies featuring pollen DNA metabarcoding, which highlighted a very high heterogeneity of filtering methods. We assessed how these strategies shaped pollen assemblage composition, species richness, and interaction networks. To do so, we compared four processing methods: unfiltering, filtering with a proportional 1% of sample reads, a fixed threshold of 100 reads, and the ROC approach (Receiver Operator Characteristic). The results indicated that filtering impacted species composition and reduced species richness, with ROC emerging as a conservative approach. Moreover, in contrast to unfiltered networks, filtering decreased network Connectance and Entropy, and it increased Modularity and Connectivity, indicating that using cut-off thresholds better describes interactions. Overall, unfiltering might compromise reliable ecological interpretations, unless a study targets rare species. We discuss the suitability of each filtering type, plead for justifying filtering strategies on biological or methodological bases and for developing shared approaches to make future studies more comparable.

Metabarcoding Analysis of Pollen Species Foraged by Osmia excavata Alfken (Hymenoptera: Megachilidae) in China

To meet the pollination need of economic crops, Osmia excavata has been successfully used to improve the pollination efficiency of Rosaceae and Brassicaceae plants. As a widely used pollinator of economic crops, a systematic study of flower-visiting species and diversities of O. excavata stocked in China was not found. To investigate the foraging pollen species and diversities of O. excavata, beebread from 20 experimental plots in China was collected by the trap-nesting method and analyzed by DNA metabarcoding technology. A total of 26 pollen plants in 14 genera and nine families were identified. A further analysis showed that the richness and abundance of the wild flowering plants in orchards and farmlands were lower than those in the nearby semi-natural habitats. The favorite pollen comes from economic crops apple and rape and wild flowering plants Juncus interior, Rosa gymnocarpa, and Rosa laevigata. Through a diversity index analysis, it was found that the Anhui region has the highest pollen plant diversity, while the Liaoning region has the lowest. Our results can provide a basis for flower-visiting species and diversities of O. excavata.

Satellite-based phenology products and in-situ pollen dynamics: A comparative assessment

Ongoing climate variability and change is impacting pollen exposure dynamics among sensitive populations. However, pollen data that can provide beneficial information to allergy experts and patients alike remains elusive. The lack of high spatial resolution pollen data has resulted in a growing interest in using phenology information that is derived using satellite observations to infer key pollen events including start of pollen season (SPS), timing of peak pollen season (PPS), and length of pollen season (LPS). However, it remains unclear if the agreement between satellite-based phenology information (e.g. start of season: SOS) and the in-situ pollen dynamics vary based on the type of satellite product itself or the processing methods used. To address this, we investigated the relationship between vegetation phenology indicator (SOS) derived from two separate sensor/satellite observations (MODIS, Landsat), and two different processing methods (double logistic regression (DLM) vs hybrid piecewise logistic regression (HPLM)) with in-situ pollen season dynamics (SPS, PPS, LPS) for three dominant allergenic tree pollen species (birch, oak, and poplar) that dominate the springtime allergy season in North America. Our results showed that irrespective of the data processing method (i.e. DLM vs HPLM), the MODIS-based SOS to be more closely aligned with the in-situ SPS, and PPS while upscaled Landsat based SOS had a better precision. The data products obtained using DLM processing methods tended to perform better than the HPLM based methods. We further showed that MODIS based phenology information along with temperature and latitude can be used to infer in-situ pollen dynamic for tree pollen during spring time. Our findings suggest that satellite-based phenology information may be useful in the development of early warning systems for allergic diseases.

Lag associations of four types of pollens with respiratory mortality in Michigan 2006-2021

BACKGROUND AND AIM: Research on associations between pollen and mortality from respiratory-related causes, such as pneumonia and chronic obstructive pulmonary disease (COPD), is limited. Levels of plant-based aeroallergens such as common ragweed are rising as growing seasons lengthen and CO2 levels rise. We determined associations of four species of pollens, ragweed, deciduous trees, grass and evergreen trees with pneumonia and COPD-related mortality in Michigan, USA. METHODS: Death records were obtained for all deaths within Michigan for the years 2006 through 2021 from the Michigan Department of Health and Human Services (MDHHS). The dataset was filtered on specific causes of death based on International Classification of Diseases (ICD) codes. Pollen data came from a prognostic model based raster of daily pollen counts at 25km resolution. Case-crossover models with distributed lag non-linear bases for pollen were used to test associations between lags of daily pollen counts with mortality. RESULTS:Among 1,399,714 deaths between 2006 and 2021, 130,584 were from all respiratory causes, 71,427 from COPD and 22,723 from pneumonia. Of the four pollen types, only ragweed was found to be associated with all-cause respiratory mortality, and only for high concentrations (100-200 grains/m3) at lags 5-8. Similarly, only ragweed was associated with deaths from COPD and only at lags 4-8 for high concentrations (100-300 grains/m3.) Short term exposures (lags 0-2) of increasing intensity to grass pollens were suggestive of increased risk of death from pneumonia, but this relationship was not significant. CONCLUSIONS:Our results suggest relationships of exposures of pollens of specific plants with specific causes of death. Intense exposure to ragweed pollens may increase risk for mortality from COPD or other respiratory causes, and grass pollens might be associated with death from pneumonia. Future work will consider how model-based predictions of pollen counts can be used to test associations of pollen exposure with mortality risk over wide areas. KEYWORDS: allergy, pollen, climate change, respiratory, copd, mortality

Rationale, design and preliminary results of a panel study investigating six health effects of airborne pollen: the EPOCHAL study

BACKGROUND AND AIM: While airborne pollen is widely recognized as a seasonal cause of sneezing and itchy eyes, its systemic health effects on pulmonary function, cardiovascular health, sleep quality, and cognitive performance are less well-established. Further, it is likely that the public health impact of pollen may increase in the future due to two trends in the last decades: higher population prevalence of pollen sensitization as well as earlier, longer, and more intense pollen seasons, attributed to climate change. No observational study in adults has studied dose-response relationships between pollen concentration and health yet. Most studies did not confirm allergy status objectively, lacked statistical power, or were highly restrictive in their inclusion criteria, and therefore not representative of the real-world allergic population. METHODS: This work describes an overview of epidemiological research on pollen and health so far, outlining the rationale and research design of the EPOCHAL study (Effects of Pollen on Cardiorespiratory Health and ALlergies). EPOCHAL aims to relate ambient concentrations of different pollen species to six specific health outcomes. In a panel of 400 allergic and non-allergic individuals, heart rate variability and blood pressure (cardiovascular outcomes), lung function and airway inflammation (pulmonary outcomes), performance in various cognitive domains, allergic symptom severity as well as sleep and health-related quality of life are being measured repeatedly (6-16 times) over 6 weeks. RESULTS:Participant recruitment has started in March 2021 and preliminary results will be available. We aim to uncover and characterize dose-response relationships between different allergenic species of pollen and health, while evaluating concentration thresholds, linearity and plateaus. We will further explore vulnerable population subgroups, defined by sensitization profiles, demographics and comorbidities such as asthma. CONCLUSIONS:A gain of knowledge in pollen-health outcome relationships is critical to inform future environmental and health policies, provide better symptom forecasts and improve personalized prevention and medicine. KEYWORDS: Allergies, environmental epidemiology, cardiovascular diseases, respiratory outcomes, greenspace, climate

Asynchrony between solitary bee emergence and flower availability reduces flower visitation rate and may affect offspring size

Climate change can disrupt plant-pollinator interactions when shifts in the timing of pollinator activity and flowering occur unequally (i.e., phenological asynchrony). Phenological asynchrony between spring-emerging solitary bees and spring-flowering plants may cause bees to experience food deprivation that can affect their reproductive success. However, the mechanisms underlying the effects of food deprivation on solitary bee reproduction remain unknown. We investigated 1) whether food deprivation caused by phenological asynchrony affects solitary bee reproduction by influencing female lifespan and/or visitation to flowers, and 2) the relationship between the magnitude of asynchrony and bee responses. We simulated phenological asynchrony by depriving emerged female Osmia cornifrons (a spring-active solitary bee species) of nectar and pollen for 0 to 16 days. Following asynchrony treatments, we used flight cages to monitor 1) post-treatment female lifespan, 2) flower visitation, and 3) reproduction (i.e., total offspring, offspring weight, sex ratio). We found that post-treatment female lifespan was not affected by phenological asynchrony treatments, but that flower visitation rate and offspring weight decreased as the magnitude of asynchrony increased. Due to low offspring production and a lack of female offspring across treatments, we were unable to assess the effects of phenological asynchrony on total offspring produced or sex ratio. Findings suggest that post-emergence food deprivation caused by phenological asynchrony may affect offspring size by influencing nest-provisioning rates. In solitary bees, body size influences wintering survival, fecundity, and mating success. Thus, phenological asynchrony may have consequences for solitary bee populations that stem from reduced flower visitation rates, and these consequences may increase as the magnitude of asynchrony increases. Because many wild flowering plants and crops rely on pollination services provided by bees for reproductive success, bee responses to phenological asynchrony may also affect wild plant biodiversity and crop yields.

Molecular assays of pollen use consistently reflect pollinator visitation patterns in a system of flowering plants.

Determining how pollinators visit plants vs. how they carry and transfer pollen is an ongoing project in pollination ecology. The current tools for identifying the pollens that bees carry have different strengths and weaknesses when used for ecological inference. In this study we use three methods to better understand a system of congeneric, coflowering plants in the genus Clarkia and their bee pollinators: observations of plant-pollinator contact in the field, and two different molecular methods to estimate the relative abundance of each Clarkia pollen in samples collected from pollinators. We use these methods to investigate if observations of plant-pollinator contact in the field correspond to the pollen bees carry; if individual bees carry Clarkia pollens in predictable ways, based on previous knowledge of their foraging behaviors; and how the three approaches differ for understanding plant-pollinator interactions. We find that observations of plant-pollinator contact are generally predictive of the pollens that bees carry while foraging, and network topologies using the three different methods are statistically indistinguishable from each other. Results from molecular pollen analysis also show that while bees can carry multiple species of Clarkia at the same time, they often carry one species of pollen. Our work contributes to the growing body of literature aimed at resolving how pollinators use floral resources. We suggest our novel relative amplicon quantification method as another tool in the developing molecular ecology and pollination biology toolbox.

Pollen calendar to depict seasonal periodicities of airborne pollen species in a city situated in Indo-Gangetic plain, India

The growing incidences of asthma, allergic rhinitis/hayfever, and other pollen-associated allergenic diseases have become an important issue in recent years. A qualitative and quantitative evaluation of airborne pollen in Chandigarh was conducted during 2018–2020 using a Burkard volumetric-spore sampler. The Annual Pollen Integral (API) was 21,244 pollen grains/m3 in 2018-19 and 20,412 pollen grains/m3 in 2019-20, belonging to 74 pollen types. The greatest annual mean pollen percentage for 2018–2020 was attributed to Morus alba (66.74%) followed by Poaceae (6.55%), Cannabis sativa (6.74%), Celtis occidentalis (2.25%), Parthenium hysterophorus (1.51%), Eucalyptus sp. (1.37%) and remaining pollen types represented 14.84% altogether. The highest pollen concentrations were observed from February to April, corresponding to the pollen taxa seasonality that mainly contributes to the local airborne pollen spectrum. The airborne pollen calendar of Chandigarh depicts seasonal periodicities. The annual cycle shows two main seasons, i.e., a spring season dominated by arboreal pollen types (Celtis occidentalis, Eucalyptus sp., Morus alba and Pinus sp.) and autumn season dominated by herbs (Amaranthaceae/Chenopodiaceae, Cannabis sativa and Poaceae). The magnitude of start and end dates with season-length for key species were also observed, showing substantial higher pollen concentration and longer seasons length over a period of two years in Chandigarh. This seems to be linked with their extended reproductive cycle and the flowering period, including the impact of inter-year climatic variations. Identifying key allergic species and their pollen-releasing seasons, including the development of the pollen calendar, will be useful to develop strategies to reduce the impact of pollen allergy for susceptible individuals.

Relative abundance of saccharides, free amino acids, and other compounds in specific pollen species for source profiling of atmospheric aerosol

Though studies in bioaerosols are being conducted with increasing frequency over the past decade, the total breadth of knowledge on bioaerosols and their role in atmospheric processes is still minimal. In order to better characterize the chemical composition of fresh biological aerosol for purposes of source apportionment and tracing in the atmosphere, several plant pollen species were selected for detailed chemical analyses. For this purpose, different pollen species were purchased and collected around Reno, Nevada, USA, for further extraction and detailed chemical analysis. These species included aspen, corn, pecan, ragweed, eastern cottonwood, paper mulberry, rabbitbrush, bitterbrush, lodgepole pine, and Jeffrey pine. Saccharides, free amino acids, and various other polar compounds (e.g., anhydrosugars and resin acids) were quantitatively analyzed using gas chromatography and ultra-high performance liquid chromatography coupled with mass spectrometry techniques (GC–MS and UPLC-MS), with the purpose to identify differences and nuances in chemical composition of specific pollen species. The saccharides β-d-fructose, α-d-glucose, and β-d-glucose were ubiquitously found across all pollen samples (10), and sucrose was found in five samples. d-galactose was also found in pine species. Total saccharides were 4.0 to 29% of total dry weight across all samples. Total free amino acids were 0.29% to 15% of total dry weight across all samples, with the most common amino acid being proline. Chemical profiles (including both saccharides and amino acids) of surface-deposited aerosol in the Lake Tahoe area correlated most closely with pine pollen than other analyzed pollen species, indicating that chemical profiles of pollen can be used to infer its contribution to local aerosols.

Total-Evidence Phylogeny of the New World Polistes Lepeletier, 1836, Paper Wasps (Vespidae, Polistinae, Polistini)

The genus Polistes is one of the most species-rich and widely distributed groups of social wasps and a model taxon for studies of social behavior. Almost half the Polistes world fauna occurs in the New World, but their classification has been unstable due in part to the scarcity of phylogenetic studies. We investigated the phylogeny of the New World Polistes by combining a previously existing molecular dataset with a new morphological and behavioral matrix for 90 of the 93 New World species. All analyses support a single origin for the New World Polistes. All five traditionally defined New World subgenera (Aphanilopterus, Epicnemius, Fuscopolistes, Onerarius, and Palisotius) were monophyletic, but the relationships among them varied across datasets. Our results, with an expanded phenotypic dataset, improved taxonomic sampling, and enhanced clade support relative to previous studies, strongly support a classification based on five subgenera, which are all diagnosable groups supported by clear morphological synapomorphies. Hence, we propose the revalidation of previously proposed subgenera; we provide a taxonomic account of each subgenus and an identification key to all species of New World Polistes.

Segmenting 20 Types of Pollen Grains for the Cretan Pollen Dataset v1 (CPD-1)

Pollen analysis and the classification of several pollen species is an important task in melissopalynology. The development of machine learning or deep learning based classification models depends on available datasets of pollen grains from various plant species from around the globe. In this paper, Cretan Pollen Dataset v1 (CPD-1) is presented, which is a novel dataset of grains from 20 pollen species from plants gathered in Crete, Greece. The pollen grains were prepared and stained with fuchsin, in order to be captured by a camera attached to a microscope under a ×400 magnification. In addition, a pollen grain segmentation method is presented, which segments and crops each unique pollen grain and achieved an overall detection accuracy of 92%. The final dataset comprises 4034 segmented pollen grains of 20 different pollen species, as well as the raw data and ground truth, as annotated by an expert. The developed dataset is publicly accessible, which we hope will accelerate research in melissopalynology.

Rationale and Design of a Panel Study Investigating Six Health Effects of Airborne Pollen: The EPOCHAL Study.

Background: While airborne pollen is widely recognized as a seasonal cause of sneezing and itchy eyes, its effects on pulmonary function, cardiovascular health, sleep quality, and cognitive performance are less well-established. It is likely that the public health impact of pollen may increase in the future due to a higher population prevalence of pollen sensitization as well as earlier, longer, and more intense pollen seasons, trends attributed to climate change. The effects of pollen on health outcomes have previously been studied through cross-sectional design or at two time points, namely preceding and within the period of pollen exposure. We are not aware of any observational study in adults that has analyzed the dose-response relationship between daily ambient pollen concentration and cardiovascular, pulmonary, cognitive, sleep, or quality of life outcomes. Many studies have relied on self-reported pollen allergy status rather than objectively confirming pollen sensitization. In addition, many studies lacked statistical power due to small sample sizes or were highly restrictive with their inclusion criteria, making the findings less transferable to the “real world.”Methods: The EPOCHAL study is an observational panel study which aims to relate ambient pollen concentration to six specific health domains: (1) pulmonary function and inflammation; (2) cardiovascular outcomes (blood pressure and heart rate variability); (3) cognitive performance; (4) sleep; (5) health-related quality of life (HRQoL); and (6) allergic rhinitis symptom severity. Our goal is to enroll 400 individuals with diverse allergen sensitization profiles. The six health domains will be assessed while ambient exposure to pollen of different plants naturally varies. Health data will be collected through six home nurse visits (at approximately weekly intervals) as well as 10 days of independent tracking of blood pressure, sleep, cognitive performance, HRQoL, and symptom severity by participants. Through repeated health assessments, we aim to uncover and characterize dose-response relationships between exposure to different species of pollen and numerous acute health effects, considering (non-)linearity, thresholds, plateaus and slopes.Conclusion: A gain of knowledge in pollen-health outcome relationships is critical to inform future public health policies and will ultimately lead toward better symptom forecasts and improved personalized prevention and treatment.

Prevalence of Pol d 1 Sensitization in Polistes dominula Allergy and Its Diagnostic Role in Vespid Double-Positivity

Stings by Polistes species frequently cause allergic reactions. However, standard allergy diagnostics are often unable to differentiate between primary sensitization and cross-reactivity in case of Vespula/Polistes double-sensitization because antigen 5 is the only Polistes venom molecule currently available in diagnostics (Pol d 5). To evaluate the frequency of phospholipase A1 in Polistes venom allergy (Pol d 1) and its diagnostic role in vespid allergy. We performed component-resolved diagnostics in patients with vespid allergic reactions who were positive to Polistes venom. A prevalence analysis was performed and the diagnostic accuracy of Pol d 1 was evaluated to detect primary Polistes sensitization in double-sensitized patients. Blood samples were collected from 132 patients. Pol d 1 was present in 97% to 100% of 128 Polistes-positive patients. It was frequently involved in case of positivity to a single Polistes molecule (48% in double- and 80% in mono-sensitized patients). Furthermore, Pol d 1 was positive in 95% of Pold 5-negative subjects. The diagnostic accuracy of Pol d 1 was good (folded type: area under the curve= 87%; 82% sensitivity and 77% specificity at the best cutoff of 5.773), and even better when used combined with the whole extract ratio (area under the curve= 99%; 91% sensitivity and 100% specificity). The study shows that Pol d 1 is the most frequent Polistes allergen in Italian patients. It can distinguish Polistes primary sensitizations with good diagnostic accuracy, which supports its use in clinical practice.

50 Years of Pollen Monitoring in Basel (Switzerland) Demonstrate the Influence of Climate Change on Airborne Pollen.

Climate change and human impact on vegetation modify the timing and the intensity of the pollen season. The 50 years of pollen monitoring in Basel, Switzerland provide a unique opportunity to study long-term changes in pollen data. Since 1969, pollen monitoring has been carried out in Basel with a Hirst-type pollen trap. Pollen season parameters for start dates, end dates and duration were calculated with different pollen season definitions, which are commonly used in aerobiology. Intensity was analyzed by the annual pollen integral (APIn), peak value and the number of days above specific thresholds. Linear trends were calculated with the non-parametric Mann Kendall method with a Theil-Sen linear trend slope. During the last 50 years, linear increase of the monthly mean temperatures in Basel was 0.95–1.95°C in the 3 winter months, 2–3.7°C in spring months and 2.75–3.85°C in summer months. Due to this temperature increase, the start dates of the pollen season for most of the spring pollen species have advanced, from 7 days for Poaceae to 29 days for Taxus/Cupressaceae. End dates of the pollen season depend on the chosen pollen season definition. Negative trends predominate, i.e., the pollen season mostly ends earlier. Trends in the length of the pollen season depend even more on the season definitions and results are contradictory and often not significant. The intensity of the pollen season of almost all tree pollen taxa increased significantly, while the Poaceae pollen season did not change and the pollen season of herbs decreased, except for Urticaceae pollen. Climate change has a particular impact on the pollen season, but the definitions used for the pollen season parameters are crucial for the calculation of the trends. The most stable results were achieved with threshold definitions that indicate regular occurrence above certain concentrations. Percentage definitions are not recommended for trend studies when the annual pollen integral changed significantly.

Palynostratigraphy of the Lower Cretaceous Río Mayer Formation in the Río Lista area, Austral Basin, southwestern Argentina

Palynomorph assemblages were recovered from the upper levels of the Cretaceous Río Mayer Formation in the Río Lista area, Austral Basin, southern Argentina. Thirty spore and eighteen pollen species, including one angiosperm, are identified, along with fourteen dinoflagellate cysts and six acritarch taxa. The presence of Clavatipollenites spp. and the dinoflagellate cysts Muderongia mcwhaei, Diconodinium spp., and Muderongia australis suggest an early Aptian age for these palynological assemblages. Based on the relative abundance of the major groups of palynomorphs, deposition of the Rio Mayer Formation in the Río Lista area probably occurred in a progressively shallowing marine setting, evidenced by the decrease in abundance of marine elements (dinoflagellates) and the increase of Pterospermella in upper levels of the unit. These interpretations concur with sedimentological analyses of the same stratigraphic section.

The Sabrina microfloras of East Antarctica: Late Cretaceous, Paleogene or reworked?

The published latest Palaeocene to Early–Middle Eocene age limits of the Sabrina microfloras, offshore Aurora Subglacial Basin, East Antarctica, largely depend on 1970s age-range data for fossil pollen and spore species in the continental margin basins of southern Australia. This paper uses updated biostratigraphical data from southern Australia, including the basins closest to the Aurora Basin throughout the Late Cretaceous and Paleogene, to propose that the age of the terrestrial component of the Sabrina microfloras is Campanian to Maastrichtian, not Paleogene. However, the revised age limits do not preclude these microfloras being redeposited more or less intact during the development and expansion of ice-sheets on East Antarctica, i.e. most probably during the late Paleogene based on other evidence from East Antarctica.