17 research outputs found
A methodology to assess the effects of plant protection product on the homing flight of honeybee foragers
Solar Biomass Gasification Combined With Iron Oxide Reduction for Syngas Production and Green Iron Metallurgy
International audienceThe solar gasification of biomass with iron oxide for combined syngas and iron production was investigated. Both solar energy and biomass are promising renewable energies. The process of gasification converts solid carbonaceous feedstocks into either fuels or chemicals. However, conventional processes require partial combustion of the feedstock for energy supply and inherently suffer from high oxygen production costs and low syngas calorific value due to dilution with combustion products. Chemical looping gasification using solid oxides is an alternative option to tackle these issues. By supplying concentrated solar energy as the high-temperature heat source, it is possible to produce even more syngas from the process while enabling solar energy storage into dispatchable fuels. This work proposes to explore solar biomass gasification over iron oxide at high heating rates, representative of the conditions obtained in solar reactors. Thermodynamic equilibriums of gasification reactions between 100 and 1,500 • C were calculated and experimental results obtained at 1,100 • C with a specially designed induction furnace were reported for biomass gasification with iron oxide, water, or carbon dioxide as oxidizing agents. Solid products analysis showed that iron oxide can be reduced to metallic iron depending on the proportion of the oxygen carrier. These results indicate that iron oxide is an effective material for solar biomass gasification producing both syngas and iron via a novel green metallurgical process
Larval exposure to thiamethoxam and American foulbrood: effects on mortality and cognition in the honey bee Apis mellifera
Here, we examined the in vitro effects of co-exposure to a pathogen and a common neonicotinoid on honey bee larvae survival and on adult learning behavior following a standard olfactory conditioning procedure based on the proboscis extension response paradigm. We exposed or co-exposed honey bee larvae to American foulbrood and to sub-lethal doses of thiamethoxam (chronic exposure). Our results revealed no additive effects between the two stressors on larval mortality. However, the present work provides the first evidence of impaired learning and memory in adult bees that were fed thiamethoxam (0.6 ng/bee) during the larval stage. We also show no alterations in learning and memory in bees after infection with American foulbrood at the larval stage. The present study contributes to our knowledge of the sub-lethal effects of neonicotinoids on honey bee larvae and adults.En este estudio se examinaron los efectos in vitro de la co-exposiciĂłn a un patĂłgeno y un neonicotinoide comĂşn en la supervivencia de las larvas de abejas melĂferas y sobre el comportamiento de aprendizaje de adultos siguiendo un procedimiento de acondicionamiento olfativo estándar basado en el paradigma de la respuesta de extensiĂłn de la probĂłscide (PER por sus siglas en inglĂ©s). Expusimos o co-expusimos las larvas de abejas melĂferas a la loque americana y a dosis sub-letales de thiamethoxam (exposiciĂłn crĂłnica). Nuestros resultados no revelaron efectos aditivos entre los dos estresores sobre la mortalidad larvaria. Sin embargo, el presente trabajo proporciona la primera evidencia de deterioro del aprendizaje y la memoria en abejas adultas que fueron alimentadas con thiamethoxam (0,6 38 ng / abeja) durante la fase larvaria. TambiĂ©n mostramos que no hay alteraciones en el aprendizaje y la memoria en las abejas despuĂ©s de la infecciĂłn con loque americana en la fase larvaria. El presente estudio contribuye a nuestro conocimiento de los efectos sub-letales de los neonicotinoides en larvas de abejas y en adultos
Hydrogen production from solar-driven biomass gasification in a high-temperature continuously-fed solar reactor
International audienc
Ces abeilles piquées d'électronique : Les dispositifs qui révolutionnent la recherche en abeille
National audienc
Early steps of cryopreservation of day one honeybee (Apis mellifera) embryos treated with low-frequency sonophoresis
International audienceHoneybees, major providers of pollination, are endangered in many areas. Embryo cryopreservation may be avery useful tool to maintain their genetic diversity. However, it is complex in insects, because embryos are chillsensitive and are surrounded by two protectant membranes, the chorion and vitelline. These membranes preventpenetration of cryoprotectant in the embryos. This study aimed to test different conditions of embryo pre-paration before cryopreservation, including low-frequency sonophoresis, a physical method of permeabilization,and passages through cryoprotectant solutions.Apis mellifera ligusticaembryos were collected in artificial cellplugs 7.5 h after queens had been caged, in two different seasons (winter, spring) and were then incubatedinvitroovernight (16.5 h). Embryos were individually sonicated and then incubated in three cryoprotectant baths(B1 = 10%, B2 = 20% and B3 = 40% of cryoprotectant) and quenched in liquid nitrogen. Artificial cell plugsandin vitroincubation device were efficient in producing future embryos hatching. Embryos stained ruby redwith rhodamine B after sonophoresis treatment indicated that low-frequency ultrasound had permeabilizedembryos. According to the treatment, different significant hatching rates were obtained after sonophoresis (up to25%). After three cryoprotectant incubations, best hatching rates were obtained after 10 min in B1 and B2, and40 s in B3. These results show that sonophoresis is an efficient tool to permeabilize the chorion and vitellinemembrane of the day one honeybee embryo allowing a hatching rate of more than 20%. They also show that theseason is an important variability facto
CIReine - Conception d’Indicateurs de qualité des Reines d’abeilles
The objectives of this project were to develop early and non-invasive indicators for queen’s quality. Inthe same time, it proceeded (1) to the development of an electronic device to record the activity ofqueens inside the hive and to (2) test the relevance of different simple indicators (weight, colonydynamics) in connection with the performance of the colonies. It also contributed (3) to the developmentof sets of genomic markers to ensure the quality of queen mating with drones.This work began with the evaluation of the glues used for marking bee queens by beekeepers. Theresults of this study guide beekeepers towards less harmful glues for their bees. Then variousexperiments, gradually, allowed developing a system to automatic record the position of a queen insideher colony thanks to a RFID technology. This very innovative system has resulted in the creation of sixdevices that are thus available to apidologist researchers for their future research on the behavior ofbees. Experiments that have made it possible to finalize the device already bring some usefulknowledge, the absence of differences between daytime and nocturnal activity for example. It turns out,however, that the activity of a queen within her colony is relatively little related to the dynamics of it.The follow-up of nearly 300 queens throughout the project made it possible to study and disseminateknowledge on the impact of the dynamics of a colony, linked to the queen spawning, on all beekeepingperformances. The link between colony dynamics and dynamics of Varroa infestations has been studiedin detail and raised the importance of monitoring infestations on highly populated colonies in season,which, if they appear ideal for producing honey, are also subject to very strong varroas infestations.Unfortunately, simple and easily accessible criteria for beekeepers, such as the weight of queens,remained too unreliable to predict the quality of queens.The search for genetic markers to know the origin of the males which fertilized the queens should soonlead to a product available to beekeepers. It will allow breeders and conservatories to ensure the qualityof their fertilization areas.Les objectifs de ce projet étaient de développer des indicateurs précoces et non invasifs de qualité desreines d’abeilles. En parallèle, il a donc procédé (1) au développement d’un outil d’enregistrement del’activité des reines dans la ruche ainsi qu’au (2) test de la pertinence de différents indicateurs simples(poids, dynamique de colonies) en lien avec les performances des colonies. Il a par ailleurs contribué(3) à la mise au point de jeux de marqueurs génomiques permettant de s’assurer de la qualité desaccouplements des reines avec les faux bourdons.Ce travail a démarré par l’évaluation des colles utilisées pour le marquage des reines d’abeilles par lesapiculteurs. Les résultats de cette étude permettent d’orienter les apiculteurs vers des produits moinsnocifs pour les abeilles. Puis différentes expérimentations, étape par étape, ont permis de développerun système d’enregistrement automatique de la poistion d’une reine dans sa colonie grâce à unetechnologie RFID. Ce système totalement innovant a donné lieu à la création de six dispositifs qui sontainsi à disposition des chercheurs apidologues pour leurs recherches futures sur le comportement desabeilles. Les expérimentations qui ont permis de finaliser le dispositif apportent d’ores et déjà quelquesconnaissances utiles, l’absence de différences entre activité diurne et nocturne par exemple. Il s’avèreen revanche que l’activité d’une reine au sein de sa colonie est assez peu liée à la dynamique de celleci.Le suivi de près de 300 reines sur l’ensemble du projet a permis d’étudier puis diffuser lesconnaissances sur l’impact de la dynamique d’une colonie, liée à la ponte de la reine, sur toutes lesperformances d’intérêt apicole. Le lien entre la dynamique des colonies et la dynamique desinfestations de varroas a ainsi pu être étudié finement et soulever l’importance de suivre les infestationssur des colonies très populeuses en saison qui, si elles apparaissent idéales pour produire du miel, sontaussi sujetes à des infestations de varroas très fortes. Malheureusement, des critères simples etfacilement accessibles pour les apiculteurs, comme le poids des reines, demeurent trop peu fiablespour prédire la qualité des reines.La recherche de marqueurs génétiques, permettant de connaitre l’origine des mâles ayant fécondés lesreines, devrait bientôt aboutir à un produit disponible pour les apiculteurs. Il permettra ainsi auxéleveurs et aux conservatoires de s’assurer de la qualité de leurs zones de fécondation