The Experts below are selected from a list of 2568 Experts worldwide ranked by ideXlab platform
Benoit Geslin - One of the best experts on this subject based on the ideXlab platform.
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Wild Pollinator activity negatively related to honey bee colony densities in urban context
PLoS ONE, 2019Co-Authors: Lise Ropars, Isabelle Dajoz, Colin Fontaine, Audrey Muratet, Benoit GeslinAbstract:As Pollinator Decline is increasingly reported in natural and agricultural environments, cities are perceived as shelters for Pollinators because of low pesticide exposure and high floral diversity throughout the year. This has led to the development of environmental policies supporting Pollinators in urban areas. However, policies are often restricted to the promotion of honey bee colony installations, which resulted in a strong increase in apiary numbers in cities. Recently, competition for floral resources between wild Pollinators and honey bees has been highlighted in semi-natural contexts, but whether urban beekeeping could impact wild Pollinators remains unknown. Here, we show that in the city of Paris (France), wild Pollinator visitation rates are negatively correlated to honey bee colony densities present in the surrounding landscape (500m-slope =-0.614; p = 0.001-and 1000m-slope =-0.489; p = 0.005). Regarding the morphological groups of wild Pollinators, large solitary bee and beetle visitation rates were negatively affected by honey bee colony densities within a 500m buffer (slope =-0.425, p = 0.007 and slope =-0.671, p = 0.002, respectively) and bumblebee visi-tation rates were negatively affected by honey bee colony density within a 1000m buffer (slope =-0.451, p = 0.012). Further, lower interaction evenness in plant-Pollinator networks was observed with high honey bee colony density within a 1000m buffer (slope =-0.487, p = 0.008). Finally, honey bees tended to focus their foraging activity on managed rather than wild plant species (student t-test, p = 0.001) whereas wild Pollinators equally visited managed and wild species. We advocate responsible practices mitigating the introduction of high density of honey bee colonies in urban environments. Further studies are however needed to deepen our knowledge about the potential negative interactions between wild and domesticated Pollinators.
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plant Pollinator networks along a gradient of urbanisation
PLOS ONE, 2013Co-Authors: Benoit Geslin, Benoit Gauzens, Elisa Thebault, Isabelle DajozAbstract:Background: Habitat loss is one of the principal causes of the current Pollinator Decline. With agricultural intensification, increasing urbanisation is among the main drivers of habitat loss. Consequently studies focusing on Pollinator community structure along urbanisation gradients have increased in recent years. However, few studies have investigated how urbanisation affects plant-Pollinator interaction networks. Here we assessed modifications of plant-Pollinator interactions along an urbanisation gradient based on the study of their morphological relationships. Methodology/Principal Findings: Along an urbanisation gradient comprising four types of landscape contexts (semi-natural, agricultural, suburban, urban), we set up experimental plant communities containing two plant functional groups differing in their morphological traits (“open flowers” and “tubular flowers”). Insect visitations on these communities were recorded to build plant-Pollinator networks. A total of 17 857 interactions were recorded between experimental plant communities and flower-visitors. The number of interactions performed by flower-visitors was significantly lower in urban landscape context than in semi-natural and agricultural ones. In particular, insects such as Syrphidae and solitary bees that mostly visited the open flower functional group were significantly impacted by urbanisation, which was not the case for bumblebees. Urbanisation also impacted the generalism of flower-visitors and we detected higher interaction evenness in urban landscape context than in agricultural and suburban ones. Finally, in urban context, these modifications lowered the potential reproductive success of the open flowers functional group. Conclusions/Significance: Our findings show that open flower plant species and their specific flower-visitors are especially sensitive to increasing urbanisation. These results provide new clues to improve conservation measures within urbanised areas in favour of specialist flower-visitors. To complete this functional approach, studies using networks resolved to the species level along urbanised gradients would be required.
Guy Smagghe - One of the best experts on this subject based on the ideXlab platform.
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establishment of wildflower fields in poor quality landscapes enhances micro parasite prevalence in wild bumble bees
Oecologia, 2019Co-Authors: Niels Piot, Jeroen Scheper, Theo Linders, David Kleijn, Ivan Meeus, Guy SmaggheAbstract:The current worldwide Pollinator Decline is caused by the interplay of different drivers. Several strategies have been undertaken to counteract or halt this Decline, one of which is the implementation of wildflower fields. These supplementary flowers provide extra food resources and have proven their success in increasing Pollinator biodiversity and abundance. Yet such landscape alterations could also alter the host–pathogen dynamics of Pollinators, which could affect the populations. In this study, we investigated the influence of sown wildflower fields on the prevalence of micro-parasites and viruses in the wild bumble bee Bombus pascuorum, one of the most abundant bumble bee species in Europe and the Netherlands. We found that the effect of sown wildflower fields on micro-parasite prevalence is affected by the composition of the surrounding landscape and the size of the flower field. The prevalence of micro-parasites increases with increasing size of sown wildflower fields in landscapes with few semi-natural landscape elements. This effect was not observed in landscapes with a high amount of semi-natural landscape elements. We elaborate on two mechanisms which can support these findings: (1) “transmission hot spots” within the altered flower-networks, which could negatively impact hosts experiencing an increased exposure; (2) improved tolerance of the hosts, withstanding higher parasite populations.
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varroa destructor macula like virus lake sinai virus and other new rna viruses in wild bumblebee hosts bombus pascuorum bombus lapidarius and bombus pratorum
Journal of Invertebrate Pathology, 2016Co-Authors: Laurian Parmentier, Dirk C De Graaf, Guy Smagghe, Ivan MeeusAbstract:Abstract Pollinators such as bumblebees (Bombus spp.) are in Decline worldwide which poses a threat not only for ecosystem biodiversity but also to human crop production services. One main cause of Pollinator Decline may be the infection and transmission of diseases including RNA viruses. Recently, new viruses have been discovered in honeybees, but information on the presence of these in wild bumblebees is largely not available. In this study, we investigated the prevalence of new RNA viruses in Bombus species, and can report for the first time Varroa destructor Macula-like virus (VdMLV) and Lake Sinai virus (LSV) infection in multiple wild bumblebee hosts of Bombus pascuorum, Bombus lapidarius and Bombus pratorum. We sampled in 4 locations in Flanders, Belgium. Besides, we confirmed Slow bee paralysis virus (SBPV) in wild bumblebees, but no positive samples were obtained for Big Sioux river virus (BSRV). Secondly, we screened for the influence of apiaries on the prevalence of these viruses. Our results indicated a location effect for the prevalence of VdMLV in Bombus species, with a higher prevalence in the proximity of honeybee apiaries mainly observed in one location. For LSV, the prevalence was not different in the proximity or at a 1.5 km-distance of apiaries, but we reported a different isolate with similarities to LSV-2 and “LSV-clade A” as described by Ravoet et al. (2015), which was detected both in Apis mellifera and Bombus species. In general, our results indicate the existence of a disease pool of new viruses that seems to be associated to a broad range of Apoidae hosts, including multiple Bombus species.
Colin Fontaine - One of the best experts on this subject based on the ideXlab platform.
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Wild Pollinator activity negatively related to honey bee colony densities in urban context
PLoS ONE, 2019Co-Authors: Lise Ropars, Isabelle Dajoz, Colin Fontaine, Audrey Muratet, Benoit GeslinAbstract:As Pollinator Decline is increasingly reported in natural and agricultural environments, cities are perceived as shelters for Pollinators because of low pesticide exposure and high floral diversity throughout the year. This has led to the development of environmental policies supporting Pollinators in urban areas. However, policies are often restricted to the promotion of honey bee colony installations, which resulted in a strong increase in apiary numbers in cities. Recently, competition for floral resources between wild Pollinators and honey bees has been highlighted in semi-natural contexts, but whether urban beekeeping could impact wild Pollinators remains unknown. Here, we show that in the city of Paris (France), wild Pollinator visitation rates are negatively correlated to honey bee colony densities present in the surrounding landscape (500m-slope =-0.614; p = 0.001-and 1000m-slope =-0.489; p = 0.005). Regarding the morphological groups of wild Pollinators, large solitary bee and beetle visitation rates were negatively affected by honey bee colony densities within a 500m buffer (slope =-0.425, p = 0.007 and slope =-0.671, p = 0.002, respectively) and bumblebee visi-tation rates were negatively affected by honey bee colony density within a 1000m buffer (slope =-0.451, p = 0.012). Further, lower interaction evenness in plant-Pollinator networks was observed with high honey bee colony density within a 1000m buffer (slope =-0.487, p = 0.008). Finally, honey bees tended to focus their foraging activity on managed rather than wild plant species (student t-test, p = 0.001) whereas wild Pollinators equally visited managed and wild species. We advocate responsible practices mitigating the introduction of high density of honey bee colonies in urban environments. Further studies are however needed to deepen our knowledge about the potential negative interactions between wild and domesticated Pollinators.
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The Whereabouts of Flower Visitors: Contrasting Land- Use Preferences Revealed by a Country-Wide Survey Based on Citizen Science
PLoS ONE, 2012Co-Authors: Nicolas Deguines, Romain Julliard, Mathieu De Flores, Colin FontaineAbstract:Background: In the past decade, accumulating evidence of Pollinator Decline has raised concerns regarding the functioning of terrestrial ecosystems and the sustainability of crop production. Although land-use changes have been advanced as the major causes, the affinities of most wild Pollinators with the main land-use types remain unknown. Filling this gap in our knowledge is a prerequisite to improving conservation and management programmes. Methodology/Principal Findings: We estimated the affinity of flower visitors with urban, agricultural and natural land-uses using data from a country-wide scale monitoring scheme based on citizen science (Spipoll). We tested whether the affinities differed among insect orders and according to insect frequency (frequent or infrequent). Our results indicate that the affinities with the three land-use types differed among insect orders. Apart from Hymenopterans, which appeared tolerant to the different land-uses, all flower visitors presented a negative affinity with urban areas and a positive affinity with agricultural and natural areas. Additionally, infrequent taxa displayed a lower affinity with urban areas and a higher affinity with natural areas than did frequent taxa. Within frequent taxa, Hymenoptera and Coleoptera included specialists of the three land-use types whereas Diptera and Lepidoptera contained specialists of all but urban areas. Conclusions/Significance: Our approach allowed the first standardised evaluation of the affinity of flower visitors with the main land-use types across a broad taxonomical range and a wide geographic scope. Our results suggest that the most detrimental land-use change for flower visitor communities is urbanisation. Moreover, our findings highlight the fact that agricultural areas have the potential to host highly diverse Pollinator communities. We suggest that policy makers should, therefore, focus on the implementation of Pollinator-friendly practices in agricultural lands. This may be a win-win strategy, as both biodiversity and crop production may benefit from healthier communities of flower visitors in these areas.
Jean-michel Salles - One of the best experts on this subject based on the ideXlab platform.
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Land use change as a determinant of the European agricultural vulnerability confronted with Pollinator Decline
2013Co-Authors: Nicolas Gallai, Jean-michel SallesAbstract:The aim of this paper was to assess the evolution of European vulnerability to Pollinator loss inorder to determine the need for policy to protect insect Pollinators. For this purpose, we studiedthe evolution of European vulnerability across three ALARM scenarios: GRAS, BAMBU andSEDG. Those scenarios included extreme policy orientations that will affect the vulnerabilityand social welfare due to Pollinator loss. GRAS scenario policies are reactive to climate changewhile SEDG scenario policies are proactive. BAMBU scenario policies are simply anextrapolation of the 2005 policies. With proactive policies, by 2080 the vulnerability of agriculturefrom northern countries will decrease while that of Southern countries will not change. But withreactive policies, the vulnerability of Southern countries will decrease while that of Northerncountries will not change. The consumer welfare loss for consumers that prefer insect-pollinatedcrops as well as those that do not will decrease in Northern countries regardless of the scenarios.On the other hand, the consumer welfare loss of Southern countries will increase for consumersthat do not prefer insect-pollinated crops, while it will decrease for those that prefer insect-pollinated crops. The consumer welfare loss of people that have high preferences for insect-pollinated crops could even increase in the case of an accelerated increase in temperature.We found that insect Pollinators will have an important impact in the future European agriculturewhatever the political strategy undertaken (proactive or reactive). Effective actions for insectPollinator protection or for consumer welfare protection will be necessaries. This paperdemonstrated that an effective action has to be realized locally since agriculture of Europeancountries are different and will evolve differently. Furthermore the action will be differentdepending on the impact of a Pollinator Decline since it will be measured either on the agriculturalindustry or on the consumer welfare depending on the countries.
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Land use change as a determinant of the European agricultural vulnerability confronted with Pollinator Decline
2012Co-Authors: Nicolas Gallai, Jean-michel Salles, Bernard VaissièreAbstract:Insect pollination is essential for the production of a large array of crops. In the last decade, there has been evidence of a worldwide Pollinator Decline. A major pressures for this Decline seem to be land use change and agricultural intensification. Yet the policy response is not as fast as it should be. One can explain this reluctance by the low visibility of this impact into the agricultural sector in the near future. This paper analyzes the evolution in next years of the European agricultural vulnerability confronted with Pollinator Decline through the evolution of land use change. The vulnerability of agriculture to insect pollination loss is a combination of three indicators: 1) the economic value of insect pollination, 2) the vulnerability ratio, and 3) the social welfare loss. The evolution of these indicators until 2080 have been estimated in three scenarios: Growth Applied Strategy (GRAS), Business As Might Be Usual (BAMBU) and Sustainable European Development Goal (SEDG). The overall result is that the European agricultural vulnerability will increase in the near future in all scenarios and thus we demonstrate that policy is needed to protect Pollinators.
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Ecosystem services in a general equilibrium setting: the case of insect pollination
2010Co-Authors: Nicola Gallai, Charles Figuieres, Jean-michel SallesAbstract:Insect pollination is widely used for agricultural production and contributes significantly to the global value of crops. In this study, the impact of insect Pollinators on the social welfare is assessed within a general equilibrium. What would be the general consequences of a production loss due to Pollinators Decline? How are changes in profits distributed between producers of pollinated goods and other producers? These questions are studied within two alternative distribution of property rights over the firms: the case when agents possess and equal share of the firms (egalitarian ownership structure) and the case where each agent possesses one firm (polarized ownership structure). For each case, we consider the case when agent and firms are homogeneous, and the case when firms are heterogeneous. Under the egalitarian ownership structure, a Pollinator Decline will result in the decrease of the utility of both agents. When the distribution of the property right is polarized, the utility of the owner of the firm that produces the good which is not Pollinator-dependent, will increase. Under specified condition, the social welfare might increase, especially if the production function of the firm of the non dependant sector is more efficient than the other.
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Economic assessment of an insect Pollinator Decline: A general equilibrium analysis
2009Co-Authors: Nicola Gallai, Jean-michel Salles, Charles Figuieres, Bernard E. VaissiereAbstract:Insect pollination service is widely used in agriculture. This pollination service contributes significantly to the total economic value of crop production and can be valued this way. A better economic valuation is be to assess the welfare loss resulting from insect Pollinator Decline, this welfare loss being the sum of producer and consumer surplus variation. In this study, we assess the impact of insect Pollinators on the social welfare within a general equilibrium analysis. What would be the consequences of a production loss due to an insect Pollinator Decline considering the adaptation of the overall economy and more particularly considering the possible spillovers on others markets? How are changes in profits distributed between producers of pollinated goods and other producers? These two questions will be studied within two alternative scenarios for the distribution of property rights over the firms: the case where agents possess and equal share of the productive sector (the egalitarian ownership structure) and the case where each agent possess one firm (the polarized ownership structure). For each scenario, we considered two states of the economy. In the first state, agent and firms are homogeneous. In the second state, firms are heterogeneous. The social welfare is a function of the profile of consumers' utilities weighted by a ratio expressing the social preferences. We will analyze and measure the variation of the social welfare after the insect Pollinator Decline. Under the egalitarian ownership structure, we found that an insect Pollinator Decline will cause a social welfare loss. However this loss is reduced by the possibility of agents to consume the good, for which production does not depends on insect pollination. This result no longer holds when the distribution of the property right of firms is heterogeneous between agents. In this case the owner of the firm that does not produce insect pollination dependent good, would experience a gain in utility. As a result, the social welfare could increase after a Pollinator Decline. This social welfare gain would raise if production function of the firm of the non agricultural sector would be more efficient than the agricultural one.
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Economic assessment of an insect Pollinator Decline: A general equilibrium analysis
2009Co-Authors: Nicola Gallai, Jean-michel Salles, Charles Figuieres, Bernard E. VaissiereAbstract:Insect pollination service is widely used in agriculture. This pollination service contributes significantly to the total economic value of crop production. A better economic valuation is to assess the welfare loss resulting from insect Pollinator Decline, this welfare loss being the sum of producer and consumer surplus variation. In this study, we assess the impact of insect Pollinators on the social welfare within a general equilibrium analysis. What would be the consequences of a production loss due to an insect Pollinator Decline considering the adaptation of the overall economy and more particularly considering the possible spillovers on others markets? How are changes in profits distributed between producers of pollinated goods and other producers? These two questions will be studied within two alternative scenarios for the distribution of property rights over the firms: the case where agents possess and equal share of the productive sector (the egalitarian ownership structure) and the case where each agent possess one firm (the polarized ownership structure). For each scenario, we considered two states of the economy. In the first state, agent and firms are homogeneous. In the second state, firms are heterogeneous. The social welfare is a function of the profile of consumers' utilities. We will analyze and measure the variation of the social welfare after the insect Pollinator Decline. Under the egalitarian ownership structure, we found that an insect Pollinator Decline will cause a social welfare loss. However this loss is reduced by the possibility of agents to consume the good, whose production does not depends on insect pollination. This result no longer holds when the distribution of the property right is heterogeneous between agents. In this case the owner of the firm that does not produce the pollination-dependent good, would experience a gain in utility. As a result, the social welfare could increase after a Pollinator Decline. This social welfare gain would rise if the production function of the firm of the non agricultural sector would be more efficient than the agricultural one.
Bernard Vaissière - One of the best experts on this subject based on the ideXlab platform.
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Melliferous potential of some herbaceous plants in agricultural habitats
2013Co-Authors: Nicoleta Ion, Jean Francois Odoux, Bernard VaissièreAbstract:Agricultural intensification is one of the main causes of Pollinator Decline, due to the evolution of practices in recent decades. Nevertheless, crops and weeds still provide important resources for honey bees and it is there for essential to check the plants that can contribute to the sustainability of honey bees and beekeeping in agricultural habitats. Floral resources available in a farming landscape are not continuous and may result in periods of dearth. Many floral species, especially forbs, are threatened in today modern agriculture due to weeding practices, crop rotation, and the disappearance of some crops. Methods are needed to survey candidate plants that provide nectar resources, even if these are ordinary weeds but even more so if they could be of potential agricultural interest. We reviewed about 170 plant species, belonging to 120 genus and 35 botanical families, known to be visited by honey bees in agricultural habitats and assessed their melliferous potential based upon the many studies conducted in Romania. We built a large database and results from older and current studies were surveyed in order to cover the largest spectrum of species and ecological conditions. We then analysed features and relationships among species based upon their nectar secretion and ecological traits. Systematic and life history traits, functional traits and traditional use were also taken into account in order to explore cropping possibilities. Indeed, some of these species could offer new perspectives to improve agricultural habitats for honey bees.
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Land use change as a determinant of the European agricultural vulnerability confronted with Pollinator Decline
2012Co-Authors: Nicolas Gallai, Jean-michel Salles, Bernard VaissièreAbstract:Insect pollination is essential for the production of a large array of crops. In the last decade, there has been evidence of a worldwide Pollinator Decline. A major pressures for this Decline seem to be land use change and agricultural intensification. Yet the policy response is not as fast as it should be. One can explain this reluctance by the low visibility of this impact into the agricultural sector in the near future. This paper analyzes the evolution in next years of the European agricultural vulnerability confronted with Pollinator Decline through the evolution of land use change. The vulnerability of agriculture to insect pollination loss is a combination of three indicators: 1) the economic value of insect pollination, 2) the vulnerability ratio, and 3) the social welfare loss. The evolution of these indicators until 2080 have been estimated in three scenarios: Growth Applied Strategy (GRAS), Business As Might Be Usual (BAMBU) and Sustainable European Development Goal (SEDG). The overall result is that the European agricultural vulnerability will increase in the near future in all scenarios and thus we demonstrate that policy is needed to protect Pollinators.
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Evolution of agricultural vulnerability in europe confronted with Pollinator Decline: a case study comparing germany and spain
2009Co-Authors: Nicola Gallai, Jean-michel Salles, Gabriel Carre, Geoffroy Enjolras, Bernard Vaissière, Isabelle ReginsterAbstract:Here we developed economic valuations as indicators of the impact of insect Pollinators on agriculture. We calculated the value of their contribution to agriculture, crop vulnerability and the social welfare loss due to their Decline and we assessed the evolution of those indicators under the ALARM scenarios. As agricultural profi les differ between countries, we compared the impact of insect Pollinator Decline in two countries that are both important European agricultural producers, but also appear quite contrasted: Germany and Spain. The fi rst step was to valuate the contribution of insect pollination to their national agriculture. We then quantifi ed the vulnerability of national agriculture confronted with Pollinator Decline. For that purpose, we evaluated the economic loss from the Pollinator disappearance in each of these two countries based on the dependence ratio of individual crops to Pollinators based upon Klein et al. (2007). The second step was to estimate the welfare loss at the national scale. To do so, we estimated the consumer surplus loss assuming that producers might adapt at no cost to Pollinator Decline. In the last part, we discuss these indicators and analyze the possible responses aiming to prevent or alleviate the consequences of Pollinator Decline.
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Assessing the potential impact of declining insect pollination service to crops in Europe
2008Co-Authors: Bernard Vaissière, Simon G. Potts, Nicola Gallai, Gabriel Carre, Riccardo Bommarco, Kristin Krewenka, Nicolas Morison, Stuart P.m. Roberts, Ingolf Steffan-dewenter, Jean-michel SallesAbstract:In Europe, 80% of crop species are dependent upon or benefit from pollination by insects, and mostly bees. Insect pollination is both a major ecosystem service that contributes to human well-being and a production practice used by farmers. Wild bees contribute to the pollination of most crop species and their importance are increasingly recognised since their foraging activity as well as their interaction with honey bees can significantly enhance the overall pollinating activity. Yet significant Declines have been reported for wild bee populations and honey bee colonies alike in Europe. We quantified the relative importance of autonomous self-pollination, wind pollination and the pollination service provided by insects in annual entomophilous field crops over 7 to 10 sites located over a gradient of increasing semi-natural habitats in five pairs of crop-European country (ALARM EU project) : buckwheat Fagopyrum esculentum in Poland, cantaloupe Cucumis melo in France, field bean Vicia faba in the UK, spring oilseed rape Brassica napus in Sweden, and strawberry Fragaria x ananassa in Germany. Pollination service was measured on a whole plant basis, rather than using flower samples, so as to have direct access to yield data as well the quality and value of the production. Based on these results and also a larger review (Klein et al. 2007. Proc. Roy. Soc. B. 274:303-313), the potential impacts of Pollinator Decline on European agriculture will be presented in agronomic terms and also in terms of economic vulnerability.
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Economic valuation of the vulnerability of world agriculture confronted to Pollinator Decline
2008Co-Authors: Nicola Gallai, Jean-michel Salles, Josef Settele, Bernard VaissièreAbstract:There is mounting evidence of Pollinator Decline all over the world and consequences in many agricultural areas could be significant. We assessed these consequences by measuring 1) the contribution of insect pollination to the world agricultural output economic value, and 2) the vulnerability of world agriculture in the face of Pollinator Decline. We used a bioeconomic approach, which integrated the production dependence ratio on Pollinators, for the 100 crops used directly for human food worldwide as listed by FAO. The total economic value of pollination worlwide amounted to €153 billion, which represented 9.5% of the value of the world agricultural production used for human food in 2005. In terms of welfare, the consumer surplus loss was estimated between €190 and €310 billion based upon average price elasticities of –1.5 to –0.8, respectively. Vegetables and fruits were the leading crop categories in value of insect pollination with about €50 billion each, followed by edible oil crops, stimulants, nuts and spices. The production value of a ton of the crop categories that do not depend on insect pollination averaged €151 while that of those that are Pollinator dependent averaged €761. The vulnerability ratio was calculated for each crop category at the regional and world scales as the ratio between the economic value of pollination and the current total crop value. This ratio varied considerably among crop categories and there was a positive correlation between the rate of vulnerability of a crop category to Pollinators and its value per production unit. Looking at the capacity to nourish the world population after Pollinator loss, the production of 3 crop categories – namely fruits, vegetables, and stimulants– will clearly be below the current consumption level at the world scale and even more so for certain regions like Europe. Yet, although our valuation clearly demonstrates the economic importance of insect Pollinators, it cannot be considered as a scenario since it does not take into account the strategic responses of the markets.