137,247 research outputs found
Recommended from our members
Pollination services in the UK: how important are honeybees?
Pollination services are known to provide substantial benefits to human populations and agriculture in particular. Although many species are known to provide pollination services, honeybees (Apis mellifera) are often assumed to provide the majority of these services to agriculture. Using data from a range of secondary sources, this study assesses the importance of insect pollinated crops at regional and national scales and investigates the capacity of honeybees to provide optimal pollination services to UK agriculture. The findings indicate that insect pollinated crops have become increasingly important in UK crop agriculture and, as of 2007, accounted for 20% of UK cropland and 19% of total farmgate crop value. Analysis of honeybee hive numbers indicates that current UK populations are only capable of supplying 34% of pollination service demands even under favourable assumptions, falling from 70% in 1984. In spite of this decline, insect pollinated crop yields have risen by an average of 54% since 1984, casting doubt on long held beliefs that honeybees provide the majority of pollination services. Future land use and crop production patterns may further increase the role of pollination services to UK agriculture, highlighting the importance of measures aimed at maintaining both wild and managed species
Using citizen science to monitor pollination services
1. Pollination by insects is a vital ecosystem service and the need for its assessment is increasing in recognition and political pressure, but there are currently no large-scale systematic monitoring schemes in place to measure the direct provision of this service.
2. This study tested a protocol for using a citizen science approach to quantify pollination service provision in gardens and allotments, requiring participants to grow Vica faba L. plants and carry out some simple manipulations of the pollination environment (flowers with bees excluded, flowers hand-pollinated, or flowers left for local pollinators to visit). Volunteers assessed yield in the three treatments.
3. Eighty participants from across the U.K. successfully completed all parts of the protocol; a further 93 participants were unsuccessful but actively engaged with the project.
4. Overall, the present results suggest that pollination services for V. faba are currently not limiting in gardens or allotments in the U.K. It is possible and cost-effective to recruit volunteers to collect data on pollination deficits using this protocol.
5. The approach used in this paper, which could readily be extended to incorporate other plant species reliant on different guilds of pollinators, is feasible for adoption as a national monitoring scheme for pollination services.
Key words. Bees, bumblebees, crop yield, ecosystem services, pollinator, urban, Viciafab
AN EMPIRICAL ANALYSIS OF HONEYBEE POLLINATION MARKETS
Pollination by honeybees plays an important role in modern agriculture. Some crops are greatly dependent on honeybees (almonds, apples, avocados, blueberries, and cherries are examples) while the yields and quality of other crops are significantly enhanced by honeybee pollination. The importance of understanding pollination markets has increased recently due to changes brought on by the twin scourges of Varroa and tracheal mites. Both are infestations of feral and domestic bees that imply greater future reliance on domesticated bees at higher cost. In the United States a complex market has evolved that connects itinerant beekeepers and their bee colonies with farmers who demand their services. While the fields of entomology and crop science have developed a large literature on general principles of beekeeping and its application to particular crops, there has been little economic analysis of pollination markets. In this paper, we begin to remedy this lack of attention by analyzing an extensive panel data set of individual pollination transactions for Oregon beekeepers. The Oregon panel constitutes a considerably larger and richer data set on pollination markets than the data set examined by Cheung (1973), which is our only empirical precedent. Using cross-sectional time series regression models, we find results that are consistent with Cheungs earlier findings on the consistency of pollination market outcomes with economic theory. Fees charged for placing colonies on crops that yield marketable honey are found to be less than for crops that yield no honey income to the beekeeper: the pollination fee for crops that produce honey is about .40 per colony. With respect to honey prices, we find that a ten percent increase is estimated to decrease pollination fees by about $2.50 per colony. This estimated effect is a previously unexplored link between the now-defunct honey program and its longstanding public policy rationale, the encouragement of honeybee pollination. Insofar as the honey program successfully maintained the price of honey above levels that would otherwise have been observed, our analysis suggests that elimination of the program has resulted in a reduction in pollination services and an increase in pollination fees.Marketing,
Outcrossing rate of safflower (Carthamus tinctorius L.) genotypes under the agro climatic conditions of Northern Germany
Safflower oil is considered to be one of the highest quality vegetable oils for human nutrition, containing up to 90% linoleic acid. The cultivation of safflower would enlarge the number of species to increase biodiversity and widen crop rotation. Very little effort on safflower breeding has been done in Germany. The knowledge of the pollination system is a prerequisite of efficiently designing future breeding programmes. The cross pollination rate between and within plots was investigated in Göttingen (Latitude: 51° 32' North and Longitude: 9° 57' East ) in 2004 and 2005. A plot of 10 m2 of non-spiny plants was surrounded by plots of spiny plants. Ten nonspiny plants each of the border rows and of the core were harvested individually. The rate of cross pollination was calculated as the ratio of spiny to non-spiny offsprings. The average cross pollination was 6.5% (core), 9.7% (border no.1) and 18.1% (border no. 2). In a second experiment the rate of cross pollination within plots was estimated from non-spiny plants grown in mixture with spiny plants. The outcrossing rate was about 63% in 2004, but about 30% in 2005. Isolating or covering flowers by bags or cloth should be considered in pedigree breeding
Pollination patterns in safflower (Carthamus tinctorius L.) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Plant Science at Massey University
The influence of environmental conditions on safflower (Carthamus tinctorius L.) floret characters and insects were studied in relation to pollination in this species. Insect activity was studied in a field experiment using part of the world germplasm collection of safflower. Honey bees were the most likely cross-pollinators. Activity of honey bees did not vary between genotypes studied. Correlations between insect and weather data were mainly non-significant. A sample of 12 genotypes from the world collection were intensively studied in controlled environment rooms. Single plants were used as plots in a randomised complete block design, in each of four environments (day/night temperature treatments of 28/22°c and 24/l8°c in combination with vapour pressure deficit treatments of -1.0 and -0.4 kPa). Environments reflected New Zealand summer conditions. Coefficients of variation were acceptable for most characters. Considerable genotypic, environmental and genotype-environment interaction variances were observed for most characters. Standardised partial regression coefficients (path coefficients) and principal factors were utilized to determine the characters most important in self-pollination of safflower. These characters were: the length of the style-stigma; the rate of style-stigma growth; the rate of corolla tube growth and amounts of viable pollen present during floret expansion. Pollen viabilities remained high for the longest time in higher humidity environments. Large amounts of pollen were produced at the lower humidity. Floral parts were largest in the cool dry environment, however rates of style-stigma and corolla expansion were greater at lower temperatures. It was concluded that synchronization of the rates of style-stigma and corolla tube growth were important in maintaining the stigma in close proximity to viable pollen, and thus promoting the possibility of self-pollination. Self-pollination was greatest at the lower temperature and lower humidity. The basic self-pollination mechanism observed was in agreement with previous authors. A number of improvements for future controlled environment experiments involving safflower were suggested. The implications of pollination of safflower on germplasm collection and maintenance, artificial crossing and breeding plans were discussed
Recommended from our members
Hand pollination to increase seed-set of red helleborine Cephalanthera rubra in the Chiltern Hills, Buckinghamshire, England
In 2007 and in previous years, as part of ongoing attempts to improve red helleborine Cephalanthera rubra seed-set, hand pollination of florets has been undertaken at a small colony of this species in Buckinghamshire, southern England. Natural pollination rarely occurs (one mature pod recorded in 10 years) at this site. In 2007, hand pollination resulted in the production of four seed pods, of which one withered and died. Upon ripening, the three remaining pods were removed for attempted micropropagation of the seeds. Ongoing conservation management has probably benefited the solitary bee Chelostoma campanularum which now appears fairly plentiful at the site, but despite the presence of this red helleborine flower visitor, natural pollination remains virtually unrecorded at this locality; field observations suggest that C.campanularum is in fact probably not large enough to act as an effective red helleborine pollinator as it can slip in and out of the flowers without removing the pollinia, unlike it larger relative C.fuliginosum, absent from the UK but which is a known pollinator of red helleborine in continental Europe
Cumulative individual seed production in the polycarpic Caesalpinia gilliesii (Fabaceae): effects of temporal variability in floral display, plant density and pollination
In polycarpic species, floral display size and density of conspecific neighbours are time variable as well as their effects on pollination and fecundity. Here, we address how individual pollinator-dependent seed production responds to changes in floral display size and the density of flowering conspecific neighbours. Using path analysis, we disentangle the partial effects of floral display size, the density of flowering neighbours and pollination intensity on the total seed output of the partially self-compatible shrub Caesalpinia gilliesii during three consecutive reproductive seasons. We also modelled the effects of temporal variability in floral offer and pollination intensity (as the coefficient of variation) on cumulative seed production over the study period. Floral display size had either positive or negative effects on pollination intensity in different reproductive seasons, but conspecific density had no significant effect within each season. However, cumulative seed production increased under lower temporal variability in conspecific density. Our results suggest that, because of the dynamic nature of floral offer in a polycarpic species, the temporal changes in floral display size and density may counteract each other reducing the risk of successive pollination failures and increasing seed production over time.Fil: Calviño, Ana Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Ashworth, Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Galetto, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin
Toward in vitro fertilization in Brachiaria spp.
Brachiaria are forage grasses widely cultivated in tropical areas. In vitro pollination was applied to accessions of Brachiaria spp. by placing pollen of non-dehiscent anthers on a solid medium near isolated ovaries. Viability and in vitro germination were tested in order to establish good conditions for pollen development. Comparing sexual to apomictic plants, apomictic pollen has more abortion after meiosis during the microspore stage and a lower viability and, of both types, only some plants have sufficient germination in a high sugar concentration. Using in vitro pollination with the sexual plant, the pollen tube penetrates into the nucellus and micropyle, but the embryo sac degenerates and collapses. In the apomictic B. decumbens, in vitro pollination leads to the transfer of the sperm nuclei into the egg cell and the central cell. The results are discussed according to normal fertilization and barriers in sexual and apomictic plants
The macroeconomic cost of catastrophic pollinator declines
We develop a computable general equilibrium (CGE) approach to assess the macroeconomic impacts of productivity shocks due to catastrophic losses of pollination ecosystem services at global and regional scales. In most regions, producers of pollinator dependent crops end up benefiting because direct output losses are outweighed by increased prices, while non-agricultural sectors experience large adverse indirect impacts, resulting in overall losses whose magnitudes vary substantially. By comparison, partial equilibrium analyses tend to overstate the costs to agricultural producers, understate aggregate economy-wide losses, and overstate the impacts on consumers' welfare. Our results suggest an upper bound on global willingness to pay for agricultural pollination services of 152 billion
Reproductive success through high pollinator visitation rates despite self incompatibility in an endangered wallflower
PREMISE OF THE STUDY: Self incompatibility (SI) in rare plants presents a unique challenge—SI protects plants from inbreeding depression, but requires a sufficient number of mates and xenogamous pollination. Does SI persist in an endangered polyploid? Is pollinator visitation sufficient to ensure reproductive success? Is there evidence of inbreeding/outbreeding depression? We characterized the mating system, primary pollinators, pollen limitation, and inbreeding/outbreeding depression in Erysimum teretifolium to guide conservation efforts. METHODS: We compared seed production following self pollination and within- and between-population crosses. Pollen tubes were visualized after self pollinations and between-population pollinations. Pollen limitation was tested in the field. Pollinator observations were quantified using digital video. Inbreeding/outbreeding depression was assessed in progeny from self and outcross pollinations at early and later developmental stages. KEY RESULTS: Self-pollination reduced seed set by 6.5× and quadrupled reproductive failure compared with outcross pollination. Pollen tubes of some self pollinations were arrested at the stigmatic surface. Seed-set data indicated strong SI, and fruit-set data suggested partial SI. Pollinator diversity and visitation rates were high, and there was no evidence of pollen limitation. Inbreeding depression (δ) was weak for early developmental stages and strong for later developmental stages, with no evidence of outbreeding depression. CONCLUSIONS: The rare hexaploid E. teretifolium is largely self incompatible and suffers from late-acting inbreeding depression. Reproductive success in natural populations was accomplished through high pollinator visitation rates consistent with a lack of pollen limitation. Future reproductive health for this species will require large population sizes with sufficient mates and a robust pollinator community
- …
