Pour savoir comment effectuer et gérer un dépôt de document, consultez le « Guide abrégé – Dépôt de documents » sur le site Web de la Bibliothèque. Pour toute question, écrivez à corpus@ulaval.ca.
 

Personne :
Fournier, Valérie

En cours de chargement...
Photo de profil

Adresse électronique

Date de naissance

Projets de recherche

Structures organisationnelles

Fonction

Nom de famille

Fournier

Prénom

Valérie

Affiliation

Université Laval. Département de phytologie

ISNI

ORCID

Identifiant Canadiana

ncf11848414

person.page.name

Résultats de recherche

Voici les éléments 1 - 6 sur 6
  • PublicationAccès libre
    Planting of neonicotinoid-coated corn raises honey bee mortality and sets back colony development
    (PeerJ Inc., 2017-08-14) Fournier, Valérie; Labrie, Geneviève; Samson-Robert, Olivier; Chagnon, Madeleine
    Worldwide occurrences of honey bee colony losses have raised concerns about bee health and the sustainability of pollination-dependent crops. While multiple causal factors have been identified, seed coating with insecticides of the neonicotinoid family has been the focus of much discussion and research. Nonetheless, few studies have investigated the impacts of these insecticides under field conditions or in commercial beekeeping operations. Given that corn-seed coating constitutes the largest single use of neonicotinoid, our study compared honey bee mortality from commercial apiaries located in two different agricultural settings, i.e. corn-dominated areas and corn-free environments, during the corn planting season. Data was collected in 2012 and 2013 from 26 bee yards. Dead honey bees from five hives in each apiary were counted and collected, and samples were analyzed using a multi-residue LC-MS/MS method. Long-term effects on colony development were simulated based on a honey bee population dynamic model. Mortality survey showed that colonies located in a corn-dominated area had daily mortality counts 3.51 times those of colonies from corn crop-free sites. Chemical analyses revealed that honey bees were exposed to various agricultural pesticides during the corn planting season, but were primarily subjected to neonicotinoid compounds (54% of analysed samples contained clothianidin, and 31% contained both clothianidin and thiamethoxam). Performance development simulations performed on hive populations’ show that increased mortality during the corn planting season sets back colony development and bears contributions to collapse risk but most of all, reduces the effectiveness and value of colonies for pollination services. Our results also have implications for the numerous large-scale and worldwide-cultivated crops that currently rely on pre-emptive use of neonicotinoid seed treatments.
  • PublicationAccès libre
    Diversity and pollen loads of flower flies (Diptera: Syrphidae) in cranberry crops
    (Entomological Society of America, 2018-08-07) Gervais, Amélie; Chagnon, Madeleine; Fournier, Valérie
    Flower flies are one of the most important groups of pollinators worldwide. Unfortunately, little is known about their pollination capacity and the importance of their role for many crops grown commercially, such as cranberries. To address this information gap, 12 cranberry farms were sampled during the blooming periods of 2013 and 2014 in Quebec, Canada, to evaluate hoverfly diversity and pollen load. Moreover, the effects of the following three factors on community structure were investigated: farm management (organic vs conventional), edge mowing (mowed vs non-mowed), and type of adjacent natural habitat (forest vs meadow vs bog). Flower flies were captured using pan-traps and hand-netting once a week for 3 wk. In total 461 specimens of flower flies were captured and 33 species were identified. Among the three factors studied, edge mowing explained most of the variation among communities, followed by farm management. Natural habitat type did not appear to influence hoverfly communities, contrary to our expectations and reports from other studies. Pollen load analyses and interactive connectance plot showed that two flower fly species, Syrphus torvus Osten Sacken and Eristalis tenax L. (Diptera: Syrphidae), transported the most cranberry pollen, both in terms of quantity and proportion. To our knowledge, this study is the first to describe and provide a complete list of flower fly species found in cranberry crops. Our results also highlight the importance of floral resource diversity for these potential cranberry pollinators, since edge mowing was revealed to be the most influential of all factors we considered.
  • PublicationAccès libre
    Neonicotinoid-contaminated puddles of water represent a risk of intoxication for honey bees
    (Public Library of Science, 2014-12-01) Labrie, Geneviève; Samson-Robert, Olivier; Chagnon, Madeleine; Fournier, Valérie
    In recent years, populations of honey bees and other pollinators have been reported to be in decline worldwide. A number of stressors have been identified as potential contributing factors, including the extensive prophylactic use of neonicotinoid insecticides, which are highly toxic to bees, in agriculture. While multiple routes of exposure to these systemic insecticides have been documented for honey bees, contamination from puddle water has not been investigated. In this study, we used a multi-residue method based on LC-MS/MS to analyze samples of puddle water taken in the field during the planting of treated corn and one month later. If honey bees were to collect and drink water from these puddles, our results showed that they would be exposed to various agricultural pesticides. All water samples collected from corn fields were contaminated with at least one neonicotinoid compound, although most contained more than one systemic insecticide. Concentrations of neonicotinoids were higher in early spring, indicating that emission and drifting of contaminated dust during sowing raises contamination levels of puddles. Although the overall average acute risk of drinking water from puddles was relatively low, concentrations of neonicotinoids ranged from 0.01 to 63 µg/L and were sufficient to potentially elicit a wide array of sublethal effects in individuals and colony alike. Our results also suggest that risk assessment of honey bee water resources underestimates the foragers' exposure and consequently miscalculates the risk. In fact, our data shows that honey bees and native pollinators are facing unprecedented cumulative exposure to these insecticides from combined residues in pollen, nectar and water. These findings not only document the impact of this route of exposure for honey bees, they also have implications for the cultivation of a wide variety of crops for which the extensive use of neonicotinoids is currently promoted.
  • PublicationAccès libre
    Assessing wild bee biodiversity in cranberry agroenvironments : influence of natural habitats
    (Oxford Oxford University Press, 2017-08-01) Gervais, Amélie; Fournier, Valérie; Sheffield, Cory Silas; Chagnon, Madeleine
    The conservation of bee populations for pollination in agricultural landscapes has attracted a lot of recent research interest, especially for crop industries undergoing expansion to meet increased production demands. In Canada, much growth has been occurring with commercial cranberry production, a field crop which is largely dependent on bee pollination. Wild bee pollinators could be negatively impacted by losses of natural habitat surrounding cranberry fields to accommodate increased production, but growers have little insight on how to manage their lands to maximize the presence of wild bees. Here, we described a 2-yr study where bee diversity and species composition were investigated to better understand the dynamic between natural habitat and cranberry fields. Bees were sampled using pan-traps and hand netting both within cranberry fields and in one of the three adjacent natural habitat types once a week during the crop flowering period. We found that bee community composition among cranberry fields did not differ based on the respective adjacent habitat type, but fields bordered by meadows were marginally less diverse than fields bordered by forest. As one would expect, field and natural habitat communities differed in terms of species composition and species richness. There was no evidence that one type of natural habitat was more favorable for the bees than another. Future agrobiodiversity studies should simultaneously examine bee diversity comprised in both crop fields and adjacent natural environments to better understand the species dynamics essential to the preservation of pollination services.
  • PublicationAccès libre
    Increased acetylcholinesterase expression in bumble bees during neonicotinoid-coated corn sowing
    (2015-07-30) Fournier, Valérie; Labrie, Geneviève; Samson-Robert, Olivier; Mercier, Pierre-Luc; Chagnon, Madeleine; Derome, Nicolas
    While honey bee exposure to systemic insecticides has received much attention, impacts on wild pollinators have not been as widely studied. Neonicotinoids have been shown to increase acetylcholinesterase (AChE) activity in honey bees at sublethal doses. High AChE levels may therefore act as a biomarker of exposure to neonicotinoids. This two-year study focused on establishing whether bumble bees living and foraging in agricultural areas using neonicotinoid crop protection show early biochemical signs of intoxication. Bumble bee colonies (Bombus impatiens) were placed in two different agricultural cropping areas: 1) control (≥3 km from fields planted with neonicotinoid-treated seeds) or 2) exposed (within 500 m of fields planted with neonicotinoid-treated seeds) and maintained for the duration of corn sowing. As determined by Real Time qPCR, AChE mRNA expression was initially significantly higher in bumble bees from exposed sites, then decreased throughout the planting season to reach a similar endpoint to that of bumble bees from control sites. These findings suggest that exposure to neonicotinoid seed coating particles during the planting season can alter bumble bee neuronal activity. To our knowledge, this is the first study to report in situ that bumble bees living in agricultural areas exhibit signs of neonicotinoid intoxication.
  • PublicationAccès libre
    Pollen diversity collected by honey bees in the vicinity of Vaccinium spp. crops and its importance for colony development
    (National Research Council of Canada, 2012-06-21) Girard, Mélissa; Chagnon, Madeleine; Fournier, Valérie
    Access to a rich diversity of flowering plants is very important for the development of honey bee colonies introduced in crops for pollination. The aim of this observational study was to determine the impact of surrounding pollen diversity on the health of honey bee colonies introduced in lowbush blueberries (Vaccinium angustifolium) in June and cranberries (V. macrocarpon) in July. The results suggest that monocultures of lowbush blueberries are not suitable for optimal brood rearing. In the blueberry environments we studied, the dominant pollen collected by honey bees were Alnus spp. and Taraxacum officinale, which are deficient in some essential amino acids. Significant reduction of brood rearing during bees’ stay in blueberry monocultures in June may therefore be explained by nutritional deficiencies. In July, the polliniferous flora in the vicinity of cranberry monocultures was poorer, but of better nutritional quality. Pollen analysis allowed the identification of Brassicaceae, Trifolium spp. and V. macrocarpon as the three dominant taxa collected by bees during this period. The complete lists of plant taxa foraged by honey bees for pollen during the pollination of lowbush blueberries and cranberries are provided.