Total Amount Of Pollen Research Articles

Pollen provisioning attenuates pesticide side-effects on a phytoseiid predator.

Biological control with predatory mites is applied against pests in greenhouse crops. Chemical control with the use of selective, reduced-risk pesticides, is an important component of Integrated Pest Management (IPM) programs, that often needs to be combined with biological control. Here, we evaluated the effect of plant pollen when used as supplementary food on the survival, reproduction and predation of the predatory mite Amblydromalus limonicus (Acari: Phytoseiidae) after exposing young larvae and adults to flonicamid, an insecticide of moderate toxicity to phytoseiids. Pollen is an important alternative food for generalist phytoseiids ensuring survival and supporting populations build-up during periods of prey scarcity. Two regimes of cattail (Typha angustifolia L.) pollen differing in application frequency were used. In the first, the total amount of pollen was supplied once, within 30 min after insecticide application, whereas in the second regime, the same amount of pollen was supplied gradually, i.e., every 48 h. Regardless of the frequency of application, pollen provisioning results in a reduction in prey (thrips) consumption relative to the control (no pollen provisioning). Nevertheless, when adult mites were directly exposed to flonicamid residues, pollen provisioning attenuated the reduction in prey consumption as compared to the control. In addition, the gradual (every 48 h) provisioning of pollen to adult predators exposed to flonicamid residues impacted positively the intrinsic rate of population increase (rm) of A. limonicus as compared to when feeding on prey. Our results reveal an unexpected role of pollen provisioning in alleviating pesticides side-effects on phytoseiids. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Optimizing the Airflow Velocity Combinations Acting on Male Parent Rows for Hybrid Rice Pollination

Highlights The effect of airflow velocity on pollen distribution was investigated under a large-scale planting mode. The response surface model between pollen distribution and airflow velocity was constructed. Multi-objective optimization of airflow velocity combinations was carried out using a genetic algorithm. The optimal airflow velocity ranges of the male parents are from 22.4 to 24 m/s, 23.1 to 27 m/s, and 23.5 to 24.1 m/s. Abstract. Pollination is the key link in hybrid rice seed production. The pneumatic pollination method can significantly improve pollination efficiency under large-scale planting mode. To investigate the effect of airflow velocity on pollen distribution in hybrid rice pollination, the velocities of airflow acting on different male parent rows were taken as the experimental factors. The pollen amount in per view and the variation rate of pollen distribution in female parent rows were used as experimental indices. Field experiments were carried out using a self-made pneumatic pollination experimental platform. The results showed that when the airflow acted on the male parents in the first and second rows of the adjacent female parent, the pollen dissemination distance was short when the airflow velocity was low, and the pollen was mainly deposited in the area near the male parents. With the increase in airflow velocity, the peak pollen amount in per view in the female parent rows gradually moved away from the male parent rows. But they are all in the female parent rows of the effective area. The total amount of pollen also increased. Due to the blocking effect of the outer male parent row, the pollen dissemination was restricted when the airflow alone acted on the third male parent row. The effect of airflow velocity on pollen distribution was not obvious. The experimental results of different airflow velocities acting on the parent row alone are used as the basis. The objective functions of pollen amount, distribution variation rate, and airflow velocities of each male parent row were established by response surface methodology. The multi-objective optimization of airflow velocity combinations was carried out by a genetic algorithm. The pollen distribution under different air velocity combinations was obtained. When the optimal airflow velocity ranges of the male parents in rows 1, 2, and 3 are 22.4 to 24 m/s, 23.1 to 27 m/s, and 23.5 to 24.1 m/s, respectively, pollination is uniform and sufficient. The research results can provide a basis for the development of pneumatic pollinators and the optimization of working parameters under large-scale planting mode. Keywords: Multi-objective parameter optimization, Pneumatic pollination machinery, Response surface modeling, Rice pollination.

Correlation of Pollen Concentration and Meteorological Factors with Medical Condition of Allergic Rhinitis in Shenyang Area.

Background The pathogenesis of allergic rhinitis (AR) was affected by meteorological and environmental factors. This study investigated the association between clinical symptoms of AR patients with pollen dispersal and meteorological conditions. Methods The clinical features of 10,838 AR patients who were treated in the Department of Otorhinolaryngology, The First Hospital of China Medical University, Shenyang, from March 2021 to October 2021 were retrospectively analyzed. We collected pollen by a pollen collector, read and counted it under a microscope, identified the species of the pollen particles, and recorded meteorological data (average daily temperature, maximum and minimum temperature, average daily wind, average daily precipitation, average daily humidity, average pressure, air quality index, PM2.5, PM10, SO2, NO2, CO, and O3), to analyze the correlation among meteorological conditions, pollen dispersal, and number of AR visits. Finally, pollen allergen-positive and symptoms were scored. Results Among the AR visits, patients >41 years old accounted for the highest proportion (64.15%). 43.67% of the patients were complicated with bronchial asthma, and the disease incidence peaked in September. During the period of the study, a total of 27,512 pollen grains were collected, and 17 species were identified. The pollens of Compositae and Moraceae were the main allergenic sources leading to the increase in AR visits from August to September. The peak of pollen dispersal was in spring, summer, and autumn. The total amount of pollen was not only related to the average daily minimum temperature, average daily precipitation, and average daily humidity but also had a significant correlation with air quality index and air pollutants (PM2.5 and PM10, SO2, NO2, and CO). In addition, there was a significant correlation between the number of daily pollen allergen-positive patients and the pollen concentration of Compositae and Moraceae as well as air pollution components. The clinical symptoms of pollen allergen-positive patients were mainly nasal congestion, red/itchy eyes, and epiphora. Conclusion The peak seasons of pollen dispersal in Shenyang were in spring, summer, and autumn, and the allergenic pollens were mainly Compositae and Moraceae. In addition, AR was substantially correlated with pollen concentration and meteorological factors. This study may help provide early warning information and prevention for AR patients.

Aerobiological monitoring in a desert type ecosystem: Two sampling stations of two cities (2017-2020) in Qatar.

The increasing number of aerobiological stations empower comparative studies to determine the relationship between pollen concentrations in different localities and the appropriate distance, which should be established between sampling stations. In Qatar, this is basically the first aerobiological study for a continuous monitoring interval. The study aimed to assess the abundance and seasonality of the most prevalent pollen types, plus identify potential differences between two sites within the country. Airborne pollen data were collected during 2017-2020 by using Hirst-type volumetric samplers in Doha capital city and Al Khor city in Qatar, placed 50 km apart. Higher total pollen indexes were recorded in the Al Khor station (2931 pollen * day/m3) compared to the Doha station (1618 pollen * day/m3). Comparing the pollen spectrum between the sampling stations revealed that ten pollen types were found in common. Amaranthaceae and Poaceae airborne pollen constituted 73.5% and 70.9% of the total amount of pollen detected at the samplers of Al Khor station and Doha station. In both sampling sites, a very pronounced seasonality was shown; August-October appeared as the period with the most intense incidence of atmospheric herbaceous pollen, with 71% and 51% of the annual total counts in Al Khor and Doha stations, respectively. August (Al Khor, 21%; Doha, 9%), September (Al Khor, 33%; Doha, 26%), October (Al Khor, 17%; Doha, 16%) were the months in which the herbs pollen concentrations were highest. Significant statistical differences between the two stations were observed in specific pollen types with local distribution in each trap's vicinity. Comparison of data obtained by the two samplers running at a distance of 50 Km indicated that potential inter-site differences could be attributed to the vegetation surrounding the city having a decisive influence on data collected.

Social disruption: Sublethal pesticides in pollen lead to Apis mellifera queen events and brood loss

Eusocial Apis mellifera colonies depend on queen longevity and brood viability to survive, as the queen is the sole reproductive individual and the maturing brood replenishes the shorter-lived worker bees. Production of many crops rely on both pesticides and bee pollination to improve crop quantity and quality, yet sublethal impacts of this pesticide exposure is often poorly understood. We investigated the resiliency of queens and their brood after one month of sublethal exposure to field relevant doses of pesticides that mimic exposure during commercial pollination contracts. We exposed full size colonies to pollen contaminated with field-relevant doses of the fungicides (chlorothalonil and propicanizole), insecticides (chlorypyrifos and fenpropathrin) or both, noting a significant reduction in pollen consumption in colonies exposed to fungicides compared to control. While we found no difference in the total amount of pollen collected per colony, a higher proportion of pollen to non-pollen foragers was detected in all pesticide exposed colonies. After ceasing treatments, we measured brood development, discovering a significant increase in brood loss and/or cannibalism across all pesticide exposed groups. Sublethal pesticide exposure in general was linked to reduced production of replacement workers and a change in protein acquisition (pollen vs. non-pollen foraging). Fungicide exposure also resulted in increased loss of the reproductive queen.

Organic winter cereals benefit bumblebee colonies in agricultural landscapes with mass‐flowering crops

Abstract Scant floral resources are a major cause of declining pollinator populations in farmland. Measures to increase floral resources on arable land include agronomically non‐productive approaches, like flowering fields (seed mixture of flowering forbs sown on fallows) and production‐integrated approaches like organically farmed crops sustaining flowering arable wild plants. However, little is known about their relative efficacy for bumblebee conservation. We observed weight gain, foraging activity, worker body size, queen brood cell number and analysed stored pollen types of Bombus terrestris colonies experimentally sited adjacent to arable fields farmed under four crop‐use types: (i) cereal mono‐crops (winter wheat) under conventional farming, (ii) non‐productive conventional flowering fields, (iii) organic cereal mono‐crops (winter spelt) and (iv) organic legume mixed‐crops (lentil mixed‐crop). Additionally, we analysed the effects of flower cover in the surrounding landscape. Colonies located adjacent to organic winter spelt fields had higher foraging activity and larger body sizes, whereas other colony performance measures were unaffected by local crop‐use type. Phacelia tanacetifolia, which was only cultivated in flowering fields, accounted for about 50% of the total pollen amount irrespective of crop‐use type. This indicated a landscape‐wide attraction for B. terrestris to flowering fields. Flower cover in the surrounding landscape did not affect colony development, but negatively affected pollen diversity. We conclude that although the pollen supply of flowering fields in the surrounding landscape strongly attracts bumblebees, local bumblebee populations could still benefit from less intensive farming practices increasing flowering wild plant diversity, such as with flower‐rich organic winter cereals.

Pollinator effectiveness in a composite: a specialist bee pollinates more florets but does not move pollen farther than other visitors.

Variation in pollinator effectiveness may contribute to pollen limitation in fragmented plant populations. In plants with multiovulate ovaries, the number of conspecific pollen grains per stigma often predicts seed set and is used to quantify pollinator effectiveness. In the Asteraceae, however, florets are uniovulate, which suggests that the total amount of pollen deposited per floret may not measure pollinator effectiveness. We examined two aspects of pollinator effectiveness-effective pollen deposition and effective pollen movement-for insects visiting Echinacea angustifolia, a composite that is pollen limited in small, isolated populations. We filmed insect visits to Echinacea in two prairie restorations and used these videos to quantify behavior that might predict effectiveness. To quantify effective pollen deposition, we used the number of styles shriveled per visit. To quantify effective pollen movement, we conducted paternity analysis on a subset of offspring and measured the pollen movement distance between mates. Effective pollen deposition varied among taxa. Andrena helianthiformis, a Heliantheae oligolege, was the most effective taxon, shriveling more than twice the proportion of styles as all other visitors. Differences in visitor behavior on a flowering head did not explain variation in effective pollen deposition, nor did flowering phenology. On average, visitors moved pollen 16 m between plants, and this distance did not vary among taxa. Andrena helianthiformis is an important pollinator of Echinacea. Variation in reproductive fitness of Echinacea in fragmented habitat may result, in part, from the abundance of this species.

The connection of pollen concentrations and crowd-sourced symptom data: new insights from daily and seasonal symptom load index data from 2013 to 2017 in Vienna

Background Online pollen diaries and mobile applications nowadays allow easy and fast documentation of pollen allergy symptoms. Such crowd-sourced symptom data provides insights into the development and the onset of a pollen allergy. Hitherto studies of the symptom load index (SLI) showed a discrepancy between the SLI and the total pollen amount of a season, but did not analyze the daily data.Methods The Patient’s Hayfever Diary (PHD) was used as data pool for symptom data. Symptom data of Vienna (Austria) was chosen as a large and local sample size within the study period of 2013 until 2017. The city was divided into three different areas based on equal population densities and different environmental factors. Correlation factors, regression lines, locally weighted smoothing (LOESS) curves and line plots were calculated to examine the data.Results Daily SLI and pollen concentration data correlates well and the progress of the SLI within a pollen season is mirrored by the pollen concentrations. The LOESS curves do not deviate much from the regression line and support the linearity of the symptom-pollen correlation on a daily basis. Seasonal SLI data does not follow the same pattern as the respective seasonal pollen indices. Results did not vary in the three areas within Vienna or when compared with the Eastern region of Austria showing no significant spatial variation of the SLI.Discussion Results indicate a linear relationship of the SLI and pollen concentrations/seasonal polllen index (SPIn) on a daily basis for both in general and throughout the season, but not on a seasonal basis. These findings clarify the frequent misinterpretation of the SLI as index that is tightly connected to pollen concentrations, but reflects as well the seasonal variation of the burden of pollen allergy sufferers.Conclusion More than just the seasonal pollen index has to be considered when the SLI of a selected pollen season has to be explained. Cross-reactivity to other pollen types, allergen content and air pollution could play a considerable role. The similar behavior of the SLI in Vienna and a whole region indicate the feasibility of a possible symptom forecast in future and justifies the use of a single pollen monitoring station within a city of the size of Vienna.

First comparison of symptom data with allergen content (Bet v 1 and Phl p 5 measurements) and pollen data from four European regions during 2009–2011

BackgroundThe level of symptoms in pollen allergy sufferers and users of the Patient's Hayfever Diary (PHD), does not directly reflect the total amount of pollen in the air. It is necessary to explain the symptom load and thus the development of allergic symptoms and to determine which environmental factors, besides the pollen load, influence variables. It seems reasonable to suspect allergen content because the amount of allergen varies throughout seasons and regions and is not always correlated with the total pollen amount. MethodsData on the allergen content of ambient air (Bet v 1 and Phl p 5) from 2009 until 2011 was used to compare the respective pollen and symptom loads for study regions in Austria, Germany, France and Finland. ResultsOur findings suggest that allergen amount (Bet v 1/Phl p 5) has a strong but regionally dependent impact on the symptom load of pollen allergy sufferers. Peak symptom loads can be traced with peak allergen loads. The influence of other important aeroallergens should also be assessed during the pollen season. ConclusionAllergen concentrations have an impact on pollen allergy sufferers although not as clear as assumed previously. The pattern of pollen load and major allergen content distribution does not directly explain the symptom load pattern, although significant positive correlations were found. Thus, monitoring of symptoms via voluntary crowdsourcing should be considered for future pollen and symptom forecasts in order to support pollen allergy sufferers.

Last glacial to post glacial climate changes in continental Asia inferred from multi-proxy records (geochemistry, clay mineralogy, and paleontology) from Lake Hovsgol, northwest Mongolia

Multi-proxy records (geochemistry, clay mineralogy and paleontology) from three sediment cores from Lake Hovsgol, northwest Mongolia, provide paleoenvironmental changes in continental Asia from the last glacial to the present (during the last 29calka BP). This paper presents the first continuous δ13C and δ18O dataset for ostracod shells (Cytherissa lacustris) from Lake Hovsgol sediments. A positive shift in ostracod δ13C values (from +0.5‰ to +3.2‰) began at ca. 21calka BP, and was associated with a decrease in δ13C values of total organic carbon (from −24.7‰ to −27.3‰) and an increase in the mass accumulation rate of total organic carbon (MAR-TOC). These results suggest that increased lake productivity led to the 13C-enrichment of dissolved inorganic carbon in Lake Hovsgol. In addition, decreases in clay content and the illite crystallinity index (full width at half maximum of the 10Å peak) began at ca. 21calka BP, indicating an increase in surface runoff and a change in sources of clastic materials in the watershed. The highest δ18Oostracod values (up to −4.8‰) at 16–15calka BP indicate the increases in precipitation from the East Asian monsoon. The total pollen amount increased, and Betula, Alnus, and Salix were dominant (up to 53%, 30%, and 6%, respectively) after 16–15calka BP. These findings indicate that broad-leaved trees expanded around Lake Hovsgol. In addition, fossil diatom valves appeared after 16–15calka BP, suggesting climate amelioration, and increased input of soil-derived nutrients and dissolved silica. Between 10 and 5calka BP (Holocene climate optimum), productivity was high in and around the lake (MAR-TOC, up to 47.3mg/cm2kyr; MAR-diatoms, up to 14.4×108 valves/cm2kyr; total pollen concentration, up to 9.0×105 grains/cm3). Environmental changes during the last 29kyr in and around Lake Hovsgol are clearly associated with fluctuations in summer insolation and East Asian monsoon intensity.

A 2-year aeropalynological survey of allergenic pollen in the atmosphere of Kastamonu, Turkey

Knowledge of airborne pollen concentrations and the weather conditions influencing them is important for air quality forecasters, allergists and allergy sufferers. For this reason, a 7-day recording volumetric spore trap of the Hirst design was used for pollen monitoring between January 2006 and December 2007 in Kastamonu, Turkey. A total of 293,427 pollen grains belonging to 51 taxa were recorded during the study period. In the 2 years of study, the period March–August was identified as the main pollination season for Kastamonu. The highest monthly pollen counts were observed in May in both years. Six taxa made up 86.5% of the total amount of pollen recorded in the atmosphere of Kastamonu. These were as follows: Pinaceae (42.9%), Cupressaceae (20.6%), Poaceae (9.7%), Quercus (5.5%) Betula (5.3%) and Carpinus (2.6%). Four of these are considered to be highly allergenic (Betula, Carpinus, Cupressaceae and Poaceae). There were also a greater percentage of highly allergenic taxa found within the city, including Betula pendula that is not part of the local flora. This shows that through urban planting, the public and municipalities can unconsciously create a high risk for allergy sufferers. Daily average pollen counts from the six most frequently recorded pollen types were entered into Spearman’s correlation analysis with meteorological data. Mean daily temperature, relative humidity, daily rainfall and wind speed were found to significantly (p < 0.05) affect atmospheric pollen concentrations, but the relationships between pollen concentrations and meteorological variables can vary and so there is a need for more local studies of this nature.

Are there changes in Germany regarding the start of the pollen season, the season length and the pollen concentration of the most important allergenic pollens?

For the regions Northwest, Northeast and Southern Germany we examined the main allergic pollen (Hazel, Alder, Birch, grasses and Mugwort) for trends on the basis of the pollen counts of the Pollen Information Service (PID) reference-stations. From these stations information about changes on the start of the pollen season, the season length and the total amount as well as the peak-concentration of pollen during the last years (1988–2009 for Northwest and Southern Germany and 1994–2009 for Northeast Germany) are examined. Possible trends are analysed by means of the Mann-Kendall test for their signif cance. The results demonstrate that the changes, regarding the start of the pollen season and the total pollen amount, are strongest in Southern and Northeast Germany. Data show for all regions that tree pollen becomes the signif cant allergen.

ヒノキ科花粉症と咽喉頭症状

Seasonal allergic rhinitis caused by Japanese cypress pollen is highly associated with that by Japanese cedar pollen, due to the similar antigen of the two pollens. Clinically, patients with cypress pollinosis complain of strong throat symptoms. Weekly nasal and throat symptoms during the pollen season in patients with Japanese cedar-cypress pollinosis were measured using a visual analog scale (VAS). Symptoms other than rhinoconjuctivitis by Japanese rhinitis quality of life questionnaire No2 were compared in two different pollen scattering-seasons. VAS showed that nasal symptoms appeared parallel with pollen scattering, and that they were severe in the cedar season more than in the cypress season. On the other hand, throat disco,fort and cough were worse in the cypress season, even though this study took place of during a year when there was only a small amount of cypress-pollen scattering. The severity of symptoms other than rhinoconjunctivitis in cedar pollinosis depended on the total amount of pollen, however, cypress pollinosis showed severe throat symptoms in both a small and a mass scattering year. Although cypress and cedar pollinosis is considered as the same disease, cypress pollinosis showed more severe symptoms other than rhinoconjunctivitis. Throat symptoms in particular are more severe in cypress pollinosis, even in the year of a small amount of scattering.

Poaceae pollen in the atmosphere of Aranjuez, Madrid and Toledo (central Spain)

The main aim of this work is to study the aerobiological behaviour of Poaceae pollen in three areas of central Spain (Aranjuez, Madrid and Toledo), all of which are similar from a geographical, climatic and biogeographical point of view, and they are located nearby one another. The samplings were carried out over a period of 4 years (2005–2008) using Hirst-type spore traps. Grass pollen is responsible for most spring allergic reactions in the pollen-sensitive population in central Spain, and they are very abundant in the atmosphere of this part of Iberian Peninsula. The average amount of this pollen type, as a percentage of the annual total pollen amount, is 7.4% in Aranjuez, 9.2% in Madrid and 11.3% in Toledo. Poaceae pollen is present in the atmosphere over a long period of time (February–October), and its maximum concentrations are detected during May and June (weeks 16–25). The city of Toledo has the highest annual concentrations of grass pollen (average 5,797 grains) with a great number of days exceeding the allergy thresholds proposed by the Spanish Aerobiology Network (REA). Madrid and Aranjuez present similar annual concentrations of grass pollen with values of 2,961 grains and 2,751 grains, respectively. The correlation analysis between the daily levels of grass pollen and meteorological variables of temperature and rainfall show a significant correlation, positive with temperature (maximum, mean and minimum) and negative with rainfall.

Plants used by Megachile (Moureapis) sp. (Hymenoptera: Megachilidae) in the provisioning of their nests

This study was carried out in the Parque Municipal das Araucárias, located in the municipality of Guarapuava (PR) from May (06) to April (07). Its aim was to investigate which plants are used by Megachile (Moureapis) sp in provisioning of larvae, and to verify if this bee is oligolectic or polilectic. The collection of the plants was carried out during the bees activity period and in an area covering a 500 m radius from where the nests had been built. A sample of pollens from founded nests and from flowers was used to make permanent slides using the acetolysis method and with the aid of a light microscope, all pollen grains were examined in order to identify the plants used by this bee. A total of 80 pollen grain slides, from 16 nests were analysed. Although 99 plants were collected close to the bee's nesting site, in nest slides, the pollen of Ludwigia peruviana (36%) and Ludwigia sericea (63.6%) (Onagraceae) accounted for 99.6% of the total amount of pollen collected. With these results we are able to conclude that Megachile (Moureapis) sp is an oligolectic species and that these plants species are their important pollen source.

Modification of bumblebee behavior by floral color change and implications for pollen transfer in Weigela middendorffiana

Flowers of Weigela middendorffiana change the color from yellow to red. The previous study revealed that red-phase flowers no longer have sexual function and nectar, and bumblebees selectively visit yellow-phase flowers. The present study examined how retaining color-changed flowers can regulate the foraging behavior of bumblebees and pollen transport among flowers within (geitonogamous pollination) and between (outcrossing pollination) plants and how the behavior is influenced by display size (i.e., number of functional flowers) and visitation frequency. The visitation frequencies of bumblebees to plants and successive flower probes within plants were observed in the field using plants whose flower number and composition of the two color-phase flowers had been manipulated. To evaluate pollination efficiency over multiple pollinator visits, a pollen transport model was constructed based on the observed bumblebee behavior. In the simulation, three flowering patterns associated with display size and existence of color-changed flowers were postulated as follows: Type 1, large display (100 functional flowers) and no retention of color-changed flowers; Type 2, small display (50 functional flowers) and retention of color-changed flowers (50 old flowers), and; Type 3, large display (100 functional flowers) and retention of color-changed flowers (100 old flowers). Color-changed flowers did not contribute to increasing bumblebee attraction at a distance but reduced the number of successive flower probes within plants. Comparisons of pollen transfer between Types 1 and 3 revealed that the retention of color-changed flowers did not influence the total amount of pollen exported when pollinator visits were abundant (>100 visits) but decreased geitonogamous pollination. Comparisons between Types 2 and 3 revealed that the discouragement effect of floral color change on successive probes accelerated in plants with a large display size. Overall, the floral color change strategy contributed to reduce geitonogamous pollination, but its effectiveness was highly sensitive to display size and pollinator frequency.

Changing pollen types/concentrations/distribution in the United States: Fact or fiction?

The buildup of greenhouse gases in the atmosphere has resulted in global climate change that is having a significant effect on many allergenic plants through increases in plant productivity and pollen allergenicity and shifts in plant phenology. Based on experimental studies, increased atmospheric levels of carbon dioxide have directly increased plant productivity. This has affected the total amount of pollen produced in some species. Research has also shown increased levels of birch allergen at warmer temperatures. Warmer temperatures have resulted in earlier flowering for many spring-flowering species in many countries, recorded through visual observations of flowering and by airborne pollen. Increases in the cumulative season totals of various pollen types also have been recorded; some of these increases may be explained by changes in plant distribution.

A scientific note on honey bee foraging activity and airborne pollen flow

Several factors affect a honey bee colony’s collection of pollen. Most studies on this topic have focused on the colony’s response to stimuli located within the nest, principally the amount of brood and stored pollen (Hrassnigg and Crailsheim, 1998; Dreller et al., 1999; Fewell and Bertram, 1999; Rotjan et al., 2002; Vaughan and Calderone, 2002). One area that has not received adequate attention is the relationship between pollen collection and its availability in the natural environment. During the last few years, aerobiology studies demonstrated a link between airborne pollen concentration and the number of flowers in the area surrounding the sampler (Reddi and Reddi, 1985; Besselat and Cour, 1990; Cunha et al., 2003; Thibaudon and Lachasse, 2005). The aim of our work was to compare the total airborne pollen flow, collected with airborne samplers, with the total amount of pollen collected by honey bee colonies. Sampling was done in the northwest littoral of Portugal, in two rural areas, Cesar (40◦55’N, 8◦25’W, 300 m altitude) and Vairao (41◦20’N, 8◦40’W, 100 m), and one urban area, Porto (41◦11’N, 8◦39’W, 50 m). Airborne pollen flow and bee-collected pollen were studied in 2003 and 2004 at Cesar and Vairao, and in 2004 at Porto. At Cesar and Vairao, the airborne pollen content was sampled using two “Cour-type” samplers (Cour, 1974) placed at 12 m and 7 m, respectively, above ground level. The pollen was trapped in filters which were changed weekly. After acetolysis (Erdtman, 1960),

A 3-year airborne pollen and fungal spores record in San Carlos de Bariloche, Patagonia, Argentina

Airborne pollen in San Carlos de Bariloche was sampled from September to March 2001–2004 with a Hirst-type volumetric spore trap placed at a height of 15 m in a city extending from the humid forests, through the mesic forests, to the steppe. The total amount of pollen recorded varied widely from year to year. The pollen index was 4,395 in the sampling period 2001/2002; 9,055 in 2002/2003 and 2,756 in 2003/2004. The main pollen period extended from October to January. In October, pollen concentration was the highest. Sixty-six pollen types were identified. Cupressaceae and Nothofagus were the major contributors. Betula, Prunus, Pinus and Populus, the most abundant ornamental taxa in the city, also contributed to the pollen record. Pollen of Maytenus and Lomatia was representative of the mesic forest, while pollen in the lower layers of the humid forest was present in trace amounts. Cupressaceae, Nothofagus and Betula prevailed during spring (September–December), and Plantago, Rumex and Poaceae during summer (December–March). The association of daily pollen concentration and meteorological variables, temperature (mean, maximum, minimum), dew point, rainfall and wind speed, was significant. Correlations showed to be negative, with the exception of that to wind speed. The total sum of fungi spores increased from 1,771 in 2001/2002; through 8,441 in 2002/2003 to 13,782 in 2003/2004. Relative concentration rose to 29%, 48% and 84% of the total number of pollen and fungal spores recorded during each sampling period.

Dynamics of pollen release in relation to anther-wall structure among species of Solanum (Solanaceae)

Dynamics of pollen release in relation to anther-wall structure among species of Solanum (sects Brevantherum, Cyphomandropsis and Pachyphylla) were studied. Differences in anther-wall qualities (multi-layered and rigid v. single-layered and flexible) were correlated with shifts between vibratory and pneumatic mechanisms. The species presented different exploitation mechanisms for bees to obtain their pollen. The number of replications (strokes on the bellows and buzzing actions) needed to empty the anthers and the total amount of pollen per flower were significantly different among the species. However, the differences were not correlated with differences in structural anther features. The pollination syndrome was related only to the total amount of pollen per flower, which was larger in the pollen flowers. We propose that the pneumatic mechanisms may have played a role simultaneously with the vibratory mechanism as an unclogging device or as a means of increasing male fitness by the pattern of pollen distribution. The pre-existence of the pneumatic principle in pollen flowers must have opened the possibility of pollen deposition on visitors without vibratory capabilities such as a male bee. Parallel to this change a shift in the reward system must have occurred.