Seasonal variation of collected pollen loads of honeybees (Apis mellifera L. anatoliaca)

Pollen collected by honeybees foraging in the region of Bursa, Turkey was analysed for a whole year. Pollen loads were collected from the hives of Apis mellifera anatoliaca once a week and were classified by colour. Forty‐one taxa were identified from the pollen analyses of the loads and 14 of these had percentages higher than 1%. Only 2.05% of the total pollen could not have been identified. Dominant taxa include; Brassicaceae (11.19%), Helianthus annuus L. (10.84%), Cichorioideae (8.93%) Salix spp. (7.99%), Rosaceae (7.37%), Centaurea spp. (7.56%), Papaver spp. (7.41%), Knautia spp. (6.99%), Fabaceae (6.01%), Asteraceae (5.73%), Xanthium spp. (2.65%), Chrozophora spp. (2.45%), Plantago spp. (1.56%) and Acer spp. (1.54%) representing 88.23% of the total. Distinct variations in plant usage are seen through the year with initial use of Rosaceae, Salix, and to a lesser extent Brassicaeae. As these groups finish flowering the bees move onto Helianthus annuus, Centaurea through the summer followed by Asteraceae in the late summer and Fabaceae in the autumn. There is a strong reliance on crop species for pollen forage but a number of indigenous species are also seen within the samples. The most productive period for collecting various pollen types, and the ideal period to determine pollen preferences of honey bees was June‐August.     

Analysis of airborne pollen fall in Sakarya, Turkey

In this study, pollen grains were identified using Durham sampler in the atmosphere of Sakarya in 2000 and 2001. During these two years, a total of 10 805 pollen grains were recorded. A total of 5 386 pollen grains per cm² were recorded in 2000 and a total of 5 419 pollen grains per cm² in 2001. Pollen fall in the years 2000–2001 comprised grains belonging to 40 taxa and some unidentified pollen grains. Of these taxa, 22 belonged to arboreal and 18 taxa to non arboreal plants. Total pollen grains consisted of 69.45% grains from arboreal plants, 28.11% grains from non-arboreal plants and 2.44% unidentified pollen grains. In the region investigated, Gramineae, Pinus sp., Quercus sp., Cupressaceae/Taxaceae, Salix sp., Platanus sp., Populus sp., Carpinus sp., Fagus sp., Chenopodiaceae/Amaranthaceae, Xanthium sp., Moraceae, Corylus sp., Fraxinus sp., and Urticaceae released the greatest amount of pollen. The season of maximum pollen fall was from March to May, with a prevalence of arboreal pollen in the first months, and of pollen from non-arboreal plants in the last months of the year.     

Air pollen dispersal in a tropical area

Volumetric data on airborne pollen have been gathered for two consecutive years at a neotropical location (Caracas). Among the 65 taxa which were identified, pollen from aCupressus species (introduced) and from aCecropia species (indigenous) were dominant. Less numerous but also abundant (daily averages ≥5 grains/m³ air) were pollen from Gramineae, Urticaceae,Alcalypha, Pinus, Piperaceae andMimosa. Pollen grains were recorded daily throughout the year. They increased in numbers during April–May and again during November–December. The first peak was contributed mainly by indigenous species, the second peak mainly by introduced species.     

Airborne pollen sampling in Toledo, Central Spain

Toledo is one of the main tourist spots of Spain, attracting around two million visitors per year. Its geographical situation in the vast and scarcely monitored Region of Castilla La Mancha and the high number of tourists (especially in the spring) has resulted in the Spanish Aerobiology Network (REA) making this city a major study objective. Air monitoring studies carried out using REA sampling procedures commenced in October 2002. Thirty-two pollen types were identified during the sampling period (October 2002 to October 2004). The annual Pollen Index (PI) was 44124 for the agricultural year October 2002–October 2003, and 29666 in the same period of 2003–2004. The most abundant taxa were, in decreasing order of dominance: Cupressaceae, Quercus, Poaceae, Populus, Olea, Urticaceae, Platanus, Pinus and Ulmus. Other, less well-represented pollen taxa included Salix, Alnus, Fraxinus and Tamarix, which were characteristic of riverside areas, and Morus, Artemisia and Chenopodiaceae. The presence of Castanea pollen grains originating from chestnut crops far away from the city was clearly an example of long-distance transport. The highest concentrations of airborne pollen were detected from March to May and also in January, due to the flowering of Cupressaceae species. In general, there was a correlation between pollen and meteorological parameters: a positive correlation with temperature and a negative correlation with rainfall and humidity during the pre-peak period. A negative correlation between temperature and some tree pollen taxa was detected in the principal pollen period correlation analysis due to their long pollination periods.     

Morphology and discrimination features of pollen from Italian olive cultivars (Olea europaea L.)

Pollen morphology of 14 cultivars of Olea europaea subsp. europaea var. europaea was analysed in order to discriminate main pollen types. The cultivars were selected from the most spread and early flowering crops grown in Italy. Morphometric parameters were observed on acetolysed pollen by means of light microscopy and scanning electron microscopy. Polar axis (P), equatorial diameter (E), P/E ratio, maximum distance between colpi in mesocolpium, distance between the apices of two colpi, exine thickness, maximum length of lumina in mesocolpium and in apocolpium, and exine reticulum thickness in mesocolpium have been measured. According to P and E, the 14 olive cultivars of this study can be divided into the three groups of small (P: 21.75 µm, E: 22.55 µm; ‘Manna’ and ‘Tonda di Cagliari’), large (P: 25.1 µm, E: 26.1 µm; ‘Pescarese’ and ‘Rotondella di Sanza’) and medium size (P: 23.49 µm, E: 24.54 µm, ‘Carolea’, ‘Grossa di Cassano’, ‘Giarraffa’, ‘Nocellara messinese’, ‘Nocellara del Belice’, ‘Santagatese’, ‘Intosso’, ‘Maiatica di Ferrandina’, ‘Nostrale di Fiano Romano’, ‘Santa Caterina’). Maximum length of lumina and exine thickness are useful parameters for further distinction of olive pollen groups, since these parameters are able to provide a specific pollen profile for each cultivar.     

Numerical analysis of surface and fossil pollen spectra from northern Fennoscandia

Aim Determination of the main directions of variance in an extensive data base of annual pollen deposition, and the relationship between pollen data from modified Tauber traps and palaeoecological data. Location Northern Finland and Norway. Methods Pollen analysis of annual samples from pollen traps and contiguous high‐resolution samples from a peat sequence. Numerical analysis (principal components analysis) of the resulting data. Results The main direction of variation in the trap data is due to the vegetation region in which each trap is located. A secondary direction of variation is due to the annual variability of pollen production of some of the tree taxa, especially Betula and Pinus. This annual variability is more conspicuous in ‘absolute’ data than it is in percentage data which, at this annual resolution, becomes more random. There are systematic differences, with respect to peat‐forming taxa, between pollen data from traps and pollen data from a peat profile collected over the same period of time. Main conclusions Annual variability in pollen production is rarely visible in fossil pollen samples because these cannot be sampled at precisely a 12‐month resolution. At near‐annual resolution sampling, it results in erratic percentage values which do not reflect changes in vegetation. Profiles sampled at near annual resolution are better analysed in terms of pollen accumulation rates with the realization that even these do not record changes in plant abundance but changes in pollen abundance. However, at the coarser temporal resolution common in most fossil samples it does not mask the origin of the pollen in terms of its vegetation region. Climate change may not be recognizable from pollen assemblages until the change has persisted in the same direction sufficiently long enough to alter the flowering (pollen production) pattern of the dominant trees.     

Seasonal variation in vegetation and pollen collected by honeybees in Thessaloniki,Greece

Pollen is important for the nutrition of honeybees and it is necessary for their survival and reproduction. In this study, we collected daily the pollen pellets from four colonies and also recorded the plants in flower in the area around the apiary, over a two‐year period. Field records revealed the presence of 204 species with Asteraceae, Fabaceae and Rosaceae being the most specious families. Although honey bees collected more than 140 pollen types, the main pollen sources (>60% of the total weight) came from less than ten taxa. The most important pollen types with respect to total weight were Sisymbrium irio, Papaver rhoeas, Verbascum sp., Polygonum aviculare, Zea mays and Olea europaea. The use of pollen traps proved a more accurate method to record the type and the foraging period during which the honeybees collect pollen, compared to field observations.     

Floral resources foraged by Geotrigona argentina (Apidae,Meliponini) in the Argentine Dry Chaco forest

This study is the first contribution to knowledge of the relationships between Geotrigona argentina and the plants of the Argentine Dry Chaco forest. A total of 1260 g of honey (corresponding to 146 pots) and 763 g of pollen (63 pots) stored in four underground nests was studied. The honey pots from each nest were homogenised and the four honey samples were analysed by melissopalynological methods, whereas the pollen pots were studied individually. Both classical counts and counts affected by the volume of the pollen types were carried out. Pollen data were statistically analysed. Additional data on both protein and lipid content is also provided. A total of 39 pollen taxa were identified. Pollen collection was focused on a few pollen taxa: Prosopis, Castela coccinea, Maytenus and Capparis; these taxa, together with Ziziphus mistol and Pisonia zapallo, were also important nectar sources. The preliminary results show that pollen collection varied seasonally, being most diverse in the summer when G. argentina incorporates herbaceous plants into its diet. The pollen collection spectrum of G. argentina is similar to that of other Trigonina bees in that the main plant species collected are a few large shrubs or trees, whose flowering consists of small and clustered flowers. Pots with large amounts of monofloral loads with pollen from only a few species suggests an organised foraging behaviour that includes the recruitment of foragers, such as that observed in other eusocial bees.     

Seasonal distribution of pollen in the atmosphere of Darwin,tropical Australia: Preliminary results

Pollen loads in the atmosphere of Darwin, a city located in the wet‐dry tropics of Australia, have been monitored for the period March 2004 to November 2005 as part of a large research program looking at atmospheric particles and human health. Seven pollen types dominate the pollen spectrum, the herbaceous families of Poaceae (grasses) and Cyperaceae (sedges), as well as several native tree and shrub taxa, Acacia, Callitris, Casuarina, Arecaceae and Myrtaceae. The pollen loads were found to have a strong seasonal component associated with the alternating wet (November to March) and dry (April to October) seasons of the region. Seventy percent of the yearly pollen load is captured during the dry season, with the peak pollen period occurring at the onset of the dry season (April–May) when most grasses are in flower. The daily pollen concentration decreases as the dry season progresses, accompanied by a change in composition; fewer herbaceous but increasing woody taxa. Preliminary health outcomes reveal a positive association between hay fever, Poaceae and Acacia pollen, as well as a significant association between total fungal spore concentrations and asthma. The Darwin record contrasts significantly with surveys conducted in the subtropical and temperate cities of Australia where temperature as opposed to rainfall and the prevalence of northern hemisphere exotic tree species have a greater influence over the seasonality and composition of the pollen loads.     

Inhibition of the growth of apple pollen tubes by EDTA, surfactants and fungicides

The effects of EDTA (ethylene diamine tetraacetic acid), Kresoxim‐methyl, Wettable Sulphur 80 WP and the surfactants Triton X‐100, Triton X‐114, Dehydol TA 5 and Dehydol TA 29 on pollen tube growth of Malus domestica, Borkh. cvs ‘Golden Delicious’ and ‘Mondial Gala’ were determined by image analysis. The ED₅₀ ‐ and ED₉₀ ‐ values (effective doses giving 50% and 90% reduction of growth) of the chemicals, except for the surfactants, were determined. The selected test substances showed an inhibiting effect on pollen tube growth, with Kresoxim‐methyl being the most active. Surfactants are components of pesticides and they also caused inhibition of pollen tube growth but only at application rates more then 10‐fold higher than typically recommended. Pollen of both apple cultivars were almost equally sensitive to the chemicals.     

Palynological analysis of five selected <Emphasis Type="Italic">Onosma</Emphasis> taxa

Pollen size and exine structure of the following five Onosma L. species from Slovakia and Italy were studied by light and scanning electron microscopy: Onosma echioides, O. tornensis, O. visianii, O. arenaria, and O. pseudoarenaria. Among the taxa studied, O. echioides has the smallest pollen grains in average (10.5–17.5 × 8.0–14.5 μm), and O. pseudoarenaria the largest grains in average (15.3–20.5 × 12.3–16.3 μm). Pollen grains of all 5 species are small sized, 3-syncolporate, subprolate, heteropolar, with ovate equatorial outlines and circular to rounded triangular polar outlines; the tectum is microechinate. A positive correlation is found between pollen size and chromosome number. The value of pollen characters for taxonomic purposes and the position of the taxa studied within the genus Onosma are discussed.     

The relationship between pollen and extant vegetation across an arid urban ecosystem and surrounding desert in Southwest USA

Aim In this paper, we explore the relationship between pollen concentration in surface soil and extant perennial vegetation across a rapidly urbanizing arid ecosystem along with its surrounding agricultural and native Sonoran Desert land. We also investigate whether taxa behave as expected from known pollination characteristics (e.g. anemophilous vs. zoophilous) and whether the pollen–plant relationship differs between the undeveloped desert and agro‐urban regions. Location We used a probability‐based sampling scheme at 200, 900‐m² sites across the Central Arizona–Phoenix region, a 6400‐km² area of the south‐western USA. Methods Pollen–plant abundances were mapped across the study area using interpolation techniques, summary bar charts and scatterplots, then two statistical approaches were applied to examine the data quantitatively. Firstly, we used regression analysis of paired pollen concentration and plant cover data; secondly, pc‐ord was used on a cross‐matrix (contingency table) containing the presence/absence scores of both pollen and plants for each taxon at each site. Results Mapping and quantitative analysis revealed that pollen–plant relationships do vary both between anemophilous and zoophilous groupings and by individual taxon. They also revealed that distribution patterns of both pollen and plant abundance vary consistently across the three main landscape types (desert, urban, agricultural) and that pollen taxa groupings are consistent with pollination method and source plant distribution regardless of landscape type. Main conclusions These findings provide a broad range of comparative data to facilitate palynological reconstruction of past vegetation and aid in assessing types of prehistoric impacts on this vegetation. They also document that significant variation can occur in pollen rain across a city, even for taxa with widely distributed pollen, leading to the conclusion that forecasting pollen distribution patterns for allergy‐related pollen types using only one or a few pollen traps is likely to entail substantial error.     

The effects of natural variation in pollinator visitation on rates of pollen removal in wild radish,Raphanus raphanistrum (Brassicaceae)

Pollen removal from flowers is an important component of male fitness, but the effects of natural variation in visitation rates on pollen removal are poorly understood. We measured pollen removal over 2 yr in experimental field populations of wild radish, Raphanus raphanistrum. Pollen removal and pollinator visitation over 1-hr periods were measured on previously unvisited flowers. The effects of pollen production and visitation by different insect taxa on pollen removal were determined using multiple regression. Pollen removal rates were extremely high; a median of 84% of pollen produced was removed in 1 hr. Pollen production was far more important than visitation in determining the number of pollen grains removed. Pollen removal increased with increasing numbers of visits by honey bees and small native bees, but increased numbers of syrphid fly visits had no effect. Average visit duration had no effect on pollen removal in 1991, and a marginally negative effect in 1992.     

Attractive Spring-food for willow grouse (Lagopus lagopus subsp. lagopus L.) studied using plant macrofossils and pollen in faeces: a methodological discussion

While macrofossil remains of herbs and flowers have disintegrated beyond identification, pollen survives the digestive process and can be identified, sometimes to species level, and is hence an important tool in determining and reconstructing animal diets.

This study compares macroscopic plant parts and pollen remains in faeces from grouse. While macroscopic remains reflect the quantity of bark, twigs, berries and leaves in the birds' food, the pollen also reflects other food, such as catkins, flower buds with developed pollen, flowers and pollen attached to leaves.

Both techniques reflect that Betula and Salix are the most important food for grouse in early Spring. Pollen analysis shows that later in Spring, after snow-melt, the birds are attracted to different plants, firstly, it is taxa within the Ericales and their fruits from the previous year. The nutrient value of food in periods with more or less snow cover is based on the environmental conditions of the previous year. Later on, different herbs, including insect-pollinated plants rich in nectar/sugar, are recorded in the pollen but are not reflected in the macro study, and are therefore lost in most calculations and not discussed. Nutrient content calculations based on Spring and Summer flowers need to be compared with the environmental and climate conditions of the current year.     

Forensic value of pollen from ornamental indoor plants

Pollen is deposited almost everywhere and can be gathered and analysed. This work is part of a survey dedicated to indoor pollen from a forensic point of view. Ornamental plants were introduced into a private flat. Their influence on the pre-existing pollen assemblages was documented. Results show that ornamental plants can dramatically change the pollen spectra of indoor locations. The severity of this impact strongly varies with different plant taxa. These findings are important for forensic investigations, since such an ‘artificial’ pollen spectrum leaves an unusual trace and could subsequently relate a suspect to a crime scene.     

Coastal dune vegetation and pollen representation in south Buenos Aires Province, Argentina

Aim To establish the relationship between coastal dune vegetation and its pollen representation as an aid to interpret Holocene vegetation dynamics and environmental changes from pollen assemblages. Location The study area is situated on the temperate Atlantic coast of south Buenos Aires Province, Argentina (c. 39° S and 61°20′ W). Methods The vegetation of the active dune area adjacent to the beach was described on the basis of its floristic composition from 25 plots. Classification of the vegetation into distinct zones was carried out by cluster analysis. Surface samples were collected from each vegetation stand and analysed for their pollen composition. Pollen percentage data were analysed using principal components analysis in order to investigate the degree to which the different vegetation units can be distinguished by their pollen spectra. Pollen–vegetation relationships for selected taxa were explored using simple scatter plots and indices of association, under‐ and over‐representation. Indices of floristic diversity and palynological richness were used to assess the representation of the vegetation in the pollen spectra. Results and conclusions Five vegetation zones are defined on the basis of species composition and their quantitative variation: back shore, mobile dunes, slacks, semi‐fixed and fixed dunes. Pollen assemblages from back shore, mobile dunes and slacks are clearly differentiated from semi‐fixed and fixed dunes. Pollen assemblages differ considerably from the associated vegetation composition. Major discrepancies are caused by large differences in pollen and vegetation proportion of Hyalis argentea and Discaria americana. There is a considerable proportion of non‐local pollen in every spectrum. Pollen representation in the coastal dunes at Monte Hermoso is influenced by differences in pollen production, dispersal and preservation of individual taxa as well as by the spatial distribution of the vegetation, the topography of the dune system and the wind pattern. The pollen–vegetation relationship established in this study has important implication for understanding and interpreting fossil pollen records from coastal dune environments.     

Pollen competition and environmental effects on hybridization dynamics between Phlox drummondii and Phlox cuspidata

Pollen competition between species strongly influences hybridization dynamics in plants. By performing single- and mixed-donor pollinations, we show that soil Ca alters the outcome of interspecific pollen competition in the annual Phlox hybrid system of Phlox cuspidata and P. drummondii. In the absence of interspecific pollen competition, heterospecific pollen siring success of both species was influenced most strongly by the maternal growth environment, such that hybridization was facilitated when heterospecific pollen was deposited on stigmas of maternal plants growing in high Ca soils. When heterospecific pollen was forced to compete against conspecific pollen, however, the maternal growth environment did not influence hybridization, but the environmental origin of heterospecific pollen did, and this effect depended on the maternal species. Pollen of P. drummondii was more effective at outcompeting P. cuspidata pollen and preventing hybridization in P. drummondii dams when P. cuspidata pollen was derived from low Ca. Pollen competition within pistils of P. cuspidata was unaffected by pollen Ca environment. In situations in which P. cuspidata grows in lower soil Ca than P. drummondii, as has been documented in one population, these results suggest that the competitive ability of heterospecific pollen will be diminished by environmental effects of soil Ca. Thus, the environment in which pollen develops can influence interspecific pollen competition and hybridization frequency.     

Nectar and Pollen Sources for Honeybee （Apis cerana cerana Fabr.） in Qinglan Mangrove Area, Hainan Island, China

In the present study, nectar and pollen sources for honeybee （Apls cerana cerana Fabr.） were studied in Qlnglan mangrove area, Hainan Island, China, based on microscopic analysis of honey and pollen load （corblcular and gut contents） from honeybees collected In October and November 2004. Qualitative and quantitative melittopalynologlcal analysis of the natural honey sample showed that the honey is of unlfloral type with Mimosa pudlca L. （Mlmosaceae） as the predominant （89.14%） source of nectar and pollen for A. cerana cerana In October. Members of Araceae are an Important minor （3%-15%） pollen type, whereas those of Arecaceae are a minor （〈3%） pollen type. Pollen grains of Nypa fruticans Wurmb., Rhlzophora spp., Excoecarla agallocha L., Lumnitzera spp., Brugulera spp., Kandella candel Druce, and Ceriops tagal （Perr.） C. B. Rob. are among the notable mangrove texa growing In Qinglan mangrove area recorded as minor taxa In the honey. The absolute pollen count （I.e. the number of pollen grains/10 g honey sample） suggests that the honey belongs to Group V （〉1 000 000）. Pollen analysis from the corblcular and gut contents of A. cerana cerana revealed the highest representation （95.60%） of members of Sonneratia spp. （Sonneratlaceae）, followed by Bruguiera spp. （Rhizophoraceae）, Euphorblaceae, Poaceae, Fabaceae, Arecaceae, Araceae, Anacardlaceae, and Rublaceae. Of these plants, those belonging to Sonneratla plants are the most Important nectar and pollen sources for A. cerana cerana and are frequently foraged and pollinated by these bees in November.     

A pre-European settlement pollen–climate calibration set for Minnesota, USA: developing tools for palaeoclimatic reconstructions

Aim The bias in modern North American pollen assemblages by landscape disturbance from Euro‐American settlement has long been overlooked in the construction of pollen–climate transfer functions. Our aim is to examine this problem and to develop an unbiased pre‐settlement pollen–climate transfer function, and to test its performance and inference power in comparison with commonly used techniques. Location Minnesota, USA, is of palaeoclimatic interest because within the state are located two continental‐scale ecotones, controlled by temperature and available moisture. Shifts of these ecotones can be tracked using palaeoecological techniques. Methods Using a data set of pre‐settlement pollen assemblages from 133 lakes, which were coupled to climate data from the earliest instrumental records (i.e. 1895–1924), a pre‐settlement pollen–climate data set was developed that lacked the influence of anthropogenic landscape disturbance. A corresponding modern pollen data set (from lake sediment core tops) and a modern climate (i.e. 1961–90) data set were also developed. The two pollen sets were compared to demonstrate the effects of landscape disturbance from human activities. Ordination (redundancy analysis with Monte Carlo permutation tests) and regression techniques (generalized linear modelling) were used to establish the relationships between the early instrumental climate variables and pre‐settlement pollen assemblages and individual taxa, respectively. Transfer functions for the most suitable climate variables (i.e. those forming a minimal set of non‐collinear climate variables that explained the greatest amount of pollen variance) were developed from the pre‐settlement data set using bootstrapping. Results Comparison of pre‐settlement pollen and modern pollen showed an over‐representation of Ambrosia, Chenopodiaceae and Poaceae, and an under‐representation of arboreal taxa (e.g. Pinus, Quercus, Ostrya) in the modern assemblages. Not surprisingly, ordination and regression techniques showed a strong relationship between the early instrumental climate variables and pre‐settlement pollen assemblages and taxa. Transfer functions were developed for May and February mean temperature and available moisture. Pre‐settlement transfer functions substantially improved the root mean squared error by 37–72% in comparison with modern transfer functions inferring pre‐settlement conditions, suggesting that the modern transfer functions have poorer predictive abilities. Main conclusions For climatic reconstructions, there can be a serious distortion of inferences based solely on modern pollen–climate data sets in regions where anthropogenic landscape disturbance has occurred. By using historical climate data, coupled with pre‐disturbance pollen assemblages, robust transfer functions for temperature and effective moisture were developed.     

An annual study of airborne pollen in northern Mexico City

An investigation of airborne pollen in northern Mexico City was carried out for one year. A total of 24 taxa were identified and classified according to the growing form in pollen of trees, weeds and grasses. Pollen grains were recorded all year round with a peak in December. The trees group showed the highest quantity of pollen as well as taxa diversity, although its peak period was in the dry season. The weeds and grasses emitted a larger quantity of pollen in the rainy season. The dominant taxa wereAlnus, Casuarina, Compositae and Gramineae. As for their relation with meteorological parameters, we found that the increase of pollen concentration was related to high temperatures, low relative humidity and high wind speed, the latter causing an increase of airborne pollen with no dilution at all. The hours with the highest pollen concentration where from 16:00 to 18:00.