Detrimental effects of clothianidin on foraging and dance communication in honey bees

Ongoing losses of pollinators are of significant international concern because of the essential role they have in our ecosystem, agriculture, and economy. Both chemical and non-chemical stressors have been implicated as possible contributors to their decline, but the increasing use of neonicotinoid insecticides has recently emerged as particularly concerning. In this study, honey bees were exposed orally to sublethal doses of the neonicotinoid clothianidin in the field in order to assess its effects on the foraging behavior, homing success, and dance communication. The foraging span and foraging activity at the contaminated feeder decreased significantly due to chronic exposure at field-realistic concentrations. Electrostatic field of dancing bees was measured and it was revealed that the number of waggle runs, the fanning time and the number of stop signals were significantly lower in the exposed colony. No difference was found in the homing success and the flight duration between control and treated bees released at a novel location within the explored area. However, a negative effect of the ambient temperature, and an influence of the location of the trained feeder was found. Finally, the residues of clothianidin accumulated in the abdomens of exposed foraging bees over time. These results show the adverse effects of a chronic exposure to sublethal doses of clothianidin on foraging and dance communication in honey bees

Altimetry for the future: Building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Altimetry for the future: building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Neonicotinoide verändern das Sammelverhalten, die Navigation, das Lernvermögen und das Gedächtnis von Honigbienen (Apis Mellifera)

The decline of pollinators worldwide is of growing concern because of the essential role they have in our ecosystem, agriculture and economy. Both biotic and abiotic factors have been implicated as possible contributors to their decline; however, the potential role(s) of commonly-used neonicotinoid insecticides has emerged as particularly concerning in the last decade. I chose to focus my research on two substances: thiacloprid, a widely used cyano-substituted neonicotinoid thought to be less toxic to honey bees and of which use has increased in the last years, and clothianidin, a nitro- substituted neonicotinoid mostly applied as seed-treatment and currently subject to a moratorium in the EU. Honey bees (Apis mellifera carnica) were chronically exposed to field-realistic concentrations of thiacloprid or clothianidin in the field for several weeks. Foraging behavior, homing success, navigation performance, and social communication were impaired by thiacloprid and residue levels increased both in the foragers and the nest mates over time. Exposure to clothianidin also impaired the foraging span, foraging behavior and recruitment abilities of honey bees in the field but the homing success was not impaired. For both substances, we showed that the effects observed in the field were not due to a repellent taste. Furthermore, we applied a laboratory standard procedure, the Proboscis Extension Response (PER) conditioning, in order to assess which processes, acquisition, memory consolidation and/or memory retrieval were compromised after bees were fed either with clothianidin, thiacloprid or the formulation of thiacloprid named Calypso® at 3 different sublethal doses. Extinction and generalization tests were performed to determine whether bees respond to a learned stimulus, and how selectively. We showed that thiacloprid, as active substance and as formulation, poses a substantial risk to honey bees by disrupting learning and memory functions. The consolidation and the retrieval of memory was also impaired in the case of bees exposed acutely to sublethal doses of clothianidin. Using both field and laboratory studies, we could show that commonly used neonicotinoids are strong candidates for the observed decline in efficiency of pollinators´ populations. Evidence that sublethal doses of thiacloprid, its formulation Calypso® and clothianidin are having such negative effects on honey bees at field-realistic concentrations raises important and challenging questions for agricultural management.Der weltweite Rückgang von Bestäubern ist von großer Bedeutung aufgrund ihrer wichtigen Rolle für die Ökosysteme, den Ackerbau und die Wirtschaft. Sowohl biotische als auch abiotische Faktoren werden als potentielle Ursachen für diesen Rückgang betrachtet. In den letzten zehn Jahren hat sich auch eine mögliche Rolle von Neonikotinoiden, den üblich verwendeten Insektiziden, herausgestellt. Für meine Forschung habe ich zwei Substanzen gewählt: Thiacloprid, ein weit verbreitetes cyano-substituiertes Neonikotinoid, das als wenig toxisch für die Honigbienen eingeschätzt wird und dessen Verwendung in den letzten Jahren rasch gestiegen ist; und Clothianidin, ein nitro- substituiertes Neonikotinoid, das meistens in der Samenbehandlung eingesetzt wird, und für das aktuell ein möglicher Zulassungsstopp in der EU geprüft wird. Honigbienen (Apis mellifera carnica) wurden über mehrere Wochen chronisch feldrealistischen Konzentrationen von Thiacloprid oder Clothianidin ausgesetzt. Die Futtersuche, erfolgreiche Nest- Rückkehr, Navigationsleistung und intraspezifische Kommunikation wurden durch Thiacloprid beeinträchtigt und seine Rückstände haben in Sammlerinnen sowie in Stockbienen im Laufe des Versuchs zugenommen. Auch die Behandlung mit Clothianidin hat die Futtersuche und die Rekrutierungsfähigkeit der Sammlerinnen beeinträchtigt und ihre Lebenserwartung verkürzt. Die Nest-Rückkehr wurde durch Clothianidin nicht beeinflusst. Wir haben für beide Substanzen nachgewiesen, dass der beobachtete Effekt nicht mit dem repellenten Geschmack zusammenhängt. Des Weiteren wurde ein standardisierter Versuch unter Laborbedingungen, die Proboscis Extension Response (PER) Konditionierung, durchgeführt, um zu erforschen, welche Prozesse der Gedächtnisbildung (der Erwerb, die Konsolidierung und/oder der Abruf des Gedächtnisses) durch die Aufnahme von Clothianidin, Thiacloprid oder einer Thiacloprid-Mixtur Calypso® in drei verschiedenen subletalen Konzentrationen beeinträchtigt werden. Extinktions- und Generalisierungsversuche wurden durchgeführt um zu bestimmen, ob und wie selektiv die Bienen auf einen gelernten Stimulus reagieren. Wir zeigen dass Thiacloprid, als reine aktive Substanz sowie in Form einer Mixtur ein erhebliches Risiko für Honigbienen, durch eine Störung der Lern- und Gedächtnisfunktion, darstellt. Die Konsolidierung und der Abruf des Gedächtnisses wurden auch nach der Aufnahme von subletalen Dosen von Clothianidin negativ beeinflusst. Durch unsere Feld- und Laborversuche wurde gezeigt, dass üblich verwendete Neonikotinoide einen starken Einfluss auf die beobachtete Abnahme der Leistung von Bestäuberpopulationen haben. Die nachgewiesene negative Wirkung der feldrealistischen subletalen Konzentrationen von Clothianidin, Thiacloprid und seiner Mixtur Calypso® auf die Honigbienen, wirft eine wichtige und herausfordernde Frage für das Agrarmanagement auf

Transfer and bioaccumulation of pesticides in terrestrial arthropods and food webs: State of knowledge and perspectives for research

International audienceArthropods represent an entry point for pesticide transfers in terrestrial food webs, and pesticide accumulation in upper chain organisms, such as predators can have cascading consequences on ecosystems. However, the mechanisms driving pesticide transfer and bioaccumulation in food webs remain poorly understood. Here we review the literature on pesticide transfers mediated by terrestrial arthropods in food webs. The transfer of pesticides and their potential for bioaccumulation and biomagnification are related to the chemical properties and toxicokinetic of the substances, the resistance and detoxification abilities of the contaminated organisms, as well as by their effects on organisms’ life history traits. We further identify four critical areas in which knowledge gain would improve future predictions of pesticides impacts on terrestrial food webs. First, efforts should be made regarding the effects of co-formulants and pesticides mixtures that are currently understudied. Second, progress in the sensitivity of analytical methods would allow the detection of low concentrations of pesticides in small individual arthropods. Quantifying pesticides in arthropods preys, their predators, and arthropods or vertebrates at higher trophic level would bring crucial insights into the bioaccumulation and biomagnification potential of pesticides in real-world terrestrial food webs. Finally, quantifying the influence of the trophic structure and complexity of communities on the transfer of pesticides could address several important sources of variability in bioaccumulation and biomagnification across species and food webs. This narrative review will inspire future studies aiming to quantify pesticide transfers in terrestrial food webs to better capture their ecological consequences in natural and cultivated landscape

La réponse du métabolome des microalgues face aux contaminations anthropiques : une revue

International audienceMicroalgae play a key role in ecosystems and are widely used in ecological status assessment. Research focusing on such organisms is then well developed and essential. Anyway, approaches for a better comprehension of their metabolome's response towards anthropogenic stressors are only emerging. This review presents the biochemical responses of various microalgae species towards several contaminants including metals and chemicals as pesticides or industrial compounds. We aim to provide a comprehensive and up-to-date overview of analytical approaches deciphering anthropogenic contaminants impact on microalgae metabolome dynamics, in order to bring out relevant biochemical markers that could be used for risk assessment. Studies to date on ecotoxicological metabolomics on microalgae are highly heterogeneous in both analytical techniques and resulting metabolite identification. There is a real need for studies using complementary approaches to determine biomarkers usable for ecological risk assessment

Effects of sublethal doses of glyphosate on honeybee navigation

Glyphosate (GLY) is a herbicide that is widely used in agriculture for weed control. Although reports about the impact of GLY in snails, crustaceans and amphibians exist, few studies have investigated its sublethal effects in non-target organisms such as the honeybee Apis mellifera, the main pollen vector in commercial crops. Here, we tested whether exposure to three sublethal concentrations of GLY (2.5, 5 and 10 mg l-1: corresponding to 0.125, 0.250 and 0.500 μg per animal) affects the homeward flight path of honeybees in an open field. We performed an experiment in which forager honeybees were trained to an artificial feeder, and then captured, fed with sugar solution containing traces of GLYand released from a novel site either once or twice. Their homeward trajectories were tracked using harmonic radar technology. We found that honeybees that had been fed with solution containing 10 mg l-1 GLY spent more time performing homeward flights than control bees or bees treated with lower concentrations. They also performed more indirect homing flights. Moreover, the proportion of direct homeward flights performed after a second release from the same site increased in control bees but not in treated bees. These results suggest that, in honeybees, exposure to levels of GLY commonly found in agricultural settings impairs the cognitive capacities needed to retrieve and integrate spatial information for a successful return to the hive. Therefore, honeybee navigation is affected by ingesting traces of the most widely used herbicide worldwide, with potential long-term negative consequences for colony foraging success.Fil: Balbuena, María Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Tison, Léa. Freie Universitat Berlin; AlemaniaFil: Hahn, Marie-Luise. Freie Universitat Berlin; AlemaniaFil: Greggers, Uwe. Freie Universitat Berlin; AlemaniaFil: Menzel, Randolf. Freie Universitat Berlin; AlemaniaFil: Farina, Walter Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

Pesticide contamination in an intensive insect predator of honey bees

Pesticides used for plant protection can indirectly affect target and non-target organisms and are identified as a major cause of insect decline. Depending on species interactions, pesticides can be transferred into the environment from plants to preys and predators. While the transfer of pesticides is often studied through vertebrate and aquatic exposure, arthropod predators of insects may represent valuable bioindicators of environmental exposure to pesticides. A modified QuEChERS extraction coupled with HPLC-MS/MS analysis was used to address the question of the exposure to pesticides of the invasive hornet Vespa velutina, a specialist predator of honey bees. This analytical method allows the accurate quantification of nanogram/gram levels of 42 contaminants in a sample weight that can be obtained from single individuals. Pesticide residues were analyzed in female workers from 24 different hornet nests and 13 different pesticides and 1 synergist, piperonyl butoxide, were identified and quantified. In 75 % of the explored nests, we found at least one compound and in 53 % of the positive samples we could quantify residues ranging from 0.5 to 19.5 ng.g−1. In this study, hornets from nests located in sub-urban environments were the most contaminated. Pesticide residue analysis in small and easy to collect predatory insects opens new perspectives for the study of environmental contamination and the transfer of pesticides in terrestrial trophic chains

Seasonal and environmental variations influencing the Varroa Sensitive Hygiene trait in the honey bee

International audienceThe invasive miteVarroa destructor is identified as the main biotic cause of European honey bee colony losses in many regions, leading to systematic treatments of colonies every year in order to prevent colonies from collapsing. However, some colonies have been reported to survive in the absence of treatment. The ability of honey bee colonies to survive varroa mite infestations has been associated with the development of Varroa Sensitive Hygiene (VSH) behavior. Colonies displaying VSH are able to detect the presence of varroa through the cap of developing brood cells and to remove the parasitized brood. To improve breeding programs for varroa resistance in apiculture, detailed knowledge of the mechanisms that enable bees to survive mite infestation and environmental conditions that can influence the expression and phenotyping of VSH behavior are needed. This study evaluated the influence of the genetic origin of the colony, the colony population dynamics, varroa density, and food supply on the ability of colonies to express the VSH trait. First, we found that varroa-selected colonies displayed lower varroa population growth rate. We also revealed that the genetic origin of the colonies and the month during which the test was performed had a significant impact on VSH behavior, with varroa-selected colonies showing higher VSH abilities than unselected colonies, and especially at the end of summer. Finally, we showed that sedentary varroa-selected colonies expressed higher VSH activity than colonies placed on lavender fields during active honey flow. Such findings are particularly important to standardize testing for varroa resistant colonies in different locations, a feature that is essential to ensure the success of breeding efforts

Seasonal variations influencing Varroa Sensitive Hygiene trait in the honey bee

National audienceVarroa resistance can be defined as the ability of honey bee colonies to survive the parasite for several years in the absence of any treatment against the mite. Long-term survival of untreated Apis mellifera populations has been reported in the US and Europe. The ability of honey bee colonies to survive varroa mite infestations has been associated with the development of Varroa Sensitive Hygiene behavior (VSH). Resistant colonies are able to detect the presence of varroa through the cap of developing brood cells and to remove parasitized brood and the mites. To improve breeding programs for varroa resistance, detailed knowledge of the mechanisms that enable bees to survive mite infestation and environmental conditions that can influence the expression and evaluation of VSH behavior are needed. This study aims at evaluating the influence of the coloniy population dynamics, the varroa density in colonies, he task allocation strategy and the food supply on the ability of colonies to expres the VSH trait. Such efforts are particularly important to standardize testing in different locations, a feature that is essential to ensure the success of breeding efforts