Impact of Nutritional Stress on Honeybee Gut Microbiota, Immunity, and Nosema ceranae Infection

Honeybees are important pollinators, having an essential role in the ecology of natural and agricultural environments. Honeybee colony losses episodes reported worldwide and have been associated with different pests and pathogens, pesticide exposure, and nutritional stress. This nutritional stress is related to the increase in monoculture areas which leads to a reduction of pollen availability and diversity. In this study, we examined whether nutritional stress affects honeybee gut microbiota, bee immunity, and infection by Nosema ceranae, under laboratory conditions. Consumption of Eucalyptus grandis pollen was used as a nutritionally poor-quality diet to study nutritional stress, in contraposition to the consumption of polyfloral pollen. Honeybees feed with Eucalyptus grandis pollen showed a lower abundance of Lactobacillus mellifer and Lactobacillus apis (Firm-4 and Firm-5, respectively) and Bifidobacterium spp. and a higher abundance of Bartonella apis, than honeybees fed with polyfloral pollen. Besides the impact of nutritional stress on honeybee microbiota, it also decreased the expression levels of vitellogenin and genes associated to immunity (glucose oxidase, hymenoptaecin and lysozyme). Finally, Eucalyptus grandis pollen favored the multiplication of Nosema ceranae. These results show that nutritional stress impacts the honeybee gut microbiota, having consequences on honeybee immunity and pathogen development. Those results may be useful to understand the influence of modern agriculture on honeybee health.Fil: Castelli, L.. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Branchiccela, B.. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Garrido, Paula Melisa. Universidad Nacional de Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente; ArgentinaFil: Invernizzi, Ciro. No especifíca;Fil: Porrini, Martín Pablo. Universidad Nacional de Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Producción, Sanidad y Ambiente; ArgentinaFil: Romero, H.. No especifíca;Fil: Santos, E.. No especifíca;Fil: Zunino, P.. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Antúnez, Karina. Instituto de Investigaciones Biológicas "Clemente Estable"; Urugua

First record of Leptus spp. (Acari: Erythraeidae) parasitizing stingless bees (Apidae: Meliponini)

The first occurrence of Leptus mites parasitizing different species of stingless bees is reported. The samples were collected in the Argentinian province of Misiones on flowers and managed stingless bee colonies. Although the frequency registered was very low, the current report is relevant as it will drive research efforts on the understanding of parasite-host dynamics, consequences at the community level, and disease management in wild and productive contexts.Fil: Martínez, Pablo Antonio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Alvarez, Leopoldo Jesús. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; ArgentinaFil: Garrido, Paula Melisa. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones en Sanidad Producción y Ambiente. - Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Instituto de Investigaciones en Sanidad Producción y Ambiente; ArgentinaFil: Porrini, Darío Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia de Buenos Aires. Municipalidad de General Pueyrredon. Secretaría de Cultura. Museo Municipal de Ciencias Naturales Lorenzo Scaglia; ArgentinaFil: Muller, Pablo Fernando. Instituto Superior de Formacion Docente Profesorado En Ciencias Agrarias y Proteccion Ambiental.; ArgentinaFil: Alberoni, Daniele. Universidad de Bologna; ItaliaFil: Porrini, Martín Pablo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones en Sanidad Producción y Ambiente. - Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Instituto de Investigaciones en Sanidad Producción y Ambiente; Argentin

Vairimorpha (Nosema) ceranae can promote Serratia development in honeybee gut: an underrated threat for bees?

The genus Serratia harbors opportunistic pathogenic species, among which Serratia marcescens is pathogenic for honeybees although little studied. Recently, virulent strains of S. marcescens colonizing the Varroa destructor mite’s mouth were found vectored into the honeybee body, leading to septicemia and death. Serratia also occurs as an opportunistic pathogen in the honeybee’s gut with a low absolute abundance. The Serratia population seems controlled by the host immune system, but its presence may represent a hidden threat, ready to arise when honeybees are weakened by biotic and abiotic stressors. To shed light on the Serratia pathogen, this research aims at studying Serratia’s development dynamics in the honeybee body and its interactions with the co-occurring fungal pathogen Vairimorpha ceranae. Firstly, the degree of pathogenicity and the ability to permeate the gut epithelial barrier of three Serratia strains, isolated from honeybees and belonging to different species (S. marcescens, Serratia liquefaciens, and Serratia nematodiphila), were assessed by artificial inoculation of newborn honeybees with different Serratia doses (104, 106, and 108 cells/mL). The absolute abundance of Serratia in the gut and in the hemocoel was assessed in qPCR with primers targeting the luxS gene. Moreover, the absolute abundance of Serratia was assessed in the gut of honeybees infected with V. ceranae at different development stages and supplied with beneficial microorganisms and fumagillin. Our results showed that all tested Serratia strains could pass through the gut epithelial barrier and proliferate in the hemocoel, with S. marcescens being the most pathogenic. Moreover, under cage conditions, Serratia better proliferates when a V. ceranae infection is co-occurring, with a positive and significant correlation. Finally, fumagillin and some of the tested beneficial microorganisms could control both Serratia and Vairimorpha development. Our findings suggest a correlation between the two pathogens under laboratory conditions, a co-occurring infection that should be taken into consideration by researches when testing antimicrobial compounds active against V. ceranae, and the related honeybees survival rate. Moreover, our findings suggest a positive control of Serratia by the environmental microorganism Apilactobacillus kunkeei in a in vivo model, confirming the potential of this specie as beneficial bacteria for honeybees

Vairimorpha (Nosema) ceranae can promote Serratia development in honeybee gut: an underrated threat for bees?

The genus Serratia harbors opportunistic pathogenic species, among which Serratia marcescens is pathogenic for honeybees although little studied. Recently, virulent strains of S. marcescens colonizing the Varroa destructor mite’s mouth were found vectored into the honeybee body, leading to septicemia and death. Serratia also occurs as an opportunistic pathogen in the honeybee’s gut with a low absolute abundance. The Serratia population seems controlled by the host immune system, but its presence may represent a hidden threat, ready to arise when honeybees are weakened by biotic and abiotic stressors. To shed light on the Serratia pathogen, this research aims at studying Serratia’s development dynamics in the honeybee body and its interactions with the co-occurring fungal pathogen Vairimorpha ceranae. Firstly, the degree of pathogenicity and the ability to permeate the gut epithelial barrier of three Serratia strains, isolated from honeybees and belonging to different species (S. marcescens, Serratia liquefaciens, and Serratia nematodiphila), were assessed by artificial inoculation of newborn honeybees with different Serratia doses (104, 106, and 108 cells/mL). The absolute abundance of Serratia in the gut and in the hemocoel was assessed in qPCR with primers targeting the luxS gene. Moreover, the absolute abundance of Serratia was assessed in the gut of honeybees infected with V. ceranae at different development stages and supplied with beneficial microorganisms and fumagillin. Our results showed that all tested Serratia strains could pass through the gut epithelial barrier and proliferate in the hemocoel, with S. marcescens being the most pathogenic. Moreover, under cage conditions, Serratia better proliferates when a V. ceranae infection is co-occurring, with a positive and significant correlation. Finally, fumagillin and some of the tested beneficial microorganisms could control both Serratia and Vairimorpha development. Our findings suggest a correlation between the two pathogens under laboratory conditions, a co-occurring infection that should be taken into consideration by researches when testing antimicrobial compounds active against V. ceranae, and the related honeybees survival rate. Moreover, our findings suggest a positive control of Serratia by the environmental microorganism Apilactobacillus kunkeei in a in vivo model, confirming the potential of this specie as beneficial bacteria for honeybees.Fil: Braglia, Chiara. Universidad de Bologna; ItaliaFil: Alberoni, Daniele. Universidad de Bologna; ItaliaFil: Garrido, Paula Melisa. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Porrini, Martín Pablo. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Baffoni, Loredana. Universidad de Bologna; ItaliaFil: Scott, Dara. No especifíca;Fil: Eguaras, Martin Javier. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Di Gioia, Diana. Universidad de Bologna; ItaliaFil: Mifsud, David. No especifíca

Combined effect of a neonicotinoid insecticide and a fungicide on honeybee gut epithelium and microbiota, adult survival, colony strength and foraging preferences

Fungicides, insecticides and herbicides are widely used in agriculture to counteract pathogens and pests. Several of these molecules are toxic to non-target organisms such as pollinators and their lethal dose can be lowered if applied as a mixture. They can cause large and unpredictable problems, spanning from behavioural changes to alterations in the gut. The present work aimed at understanding the synergistic effects on honeybees of a combined in-hive exposure to sub-lethal doses of the insecticide thiacloprid and the fungicide penconazole. A multidisciplinary approach was used: honeybee mortality upon exposure was initially tested in cage, and the colonies development monitored. Morphological and ultrastructural analyses via light and transmission electron microscopy were carried out on the gut of larvae and forager honeybees. Moreover, the main pollen foraging sources and the fungal gut microbiota were studied using Next Generation Sequencing; the gut core bacterial taxa were quantified via qPCR. The mortality test showed a negative effect on honeybee survival when exposed to agrochemicals and their mixture in cage but not confirmed at colony level. Microscopy analyses on the gut epithelium indicated no appreciable morphological changes in larvae, newly emerged and forager honeybees exposed in field to the agrochemicals. Nevertheless, the gut microbial profile showed a reduction of Bombilactobacillus and an increase of Lactobacillus and total fungi upon mixture application. Finally, we highlighted for the first time a significant honeybee diet change after pesticide exposure: penconazole, alone or in mixture, significantly altered the pollen foraging preference, with honeybees preferring Hedera pollen. Overall, our in-hive results showed no severe effects upon administration of sublethal doses of thiacloprid and penconazole but indicate a change in honeybees foraging preference. A possible explanation can be that the different nutritional profile of the pollen may offer better recovery chances to honeybees

Effects of Synthetic Acaricides and Nosema ceranae (Microsporidia: Nosematidae) on Molecules Associated with Chemical Communication and Recognition in Honey Bees

Acaricides and the gut parasite Nosema ceranae are commonly present in most productivehives. Those stressors could be affecting key semiochemicals, which act as homeostasis regulators inApis mellifera colonies, such as cuticular hydrocarbons (CHC) involved in social recognition and ethyloleate (EO) which plays a role as primer pheromone in honey bees. Here we test the effect of amitraz,coumaphos, tau-fluvalinate and flumethrin, commonly applied to treat varroosis, on honey beesurvival time, rate of food consumption, CHC profiles and EO production on N. ceranae-infected andnon-infected honey bees. Different sublethal concentrations of amitraz, coumaphos, tau-fluvalinate andflumethrin were administered chronically in a syrup-based diet. After treatment, purified hole-bodyextracts were analyzed by gas chromatography coupled to mass spectrometry. While N. ceranaeinfection was also shown to decrease EO production affecting survival rates, acaricides showed nosignificant effect on this pheromone. As for the CHC, we found no changes in relation to the healthstatus or consumption of acaricides. This absence of alteration in EO or CHC as response to acaricidesingestion or in combination with N. ceranae, suggests that worker honey bees exposed to those highlyubiquitous drugs are hardly differentiated by nest-mates. Having determined a synergic effect onmortality in worker bees exposed to coumaphos and Nosema infection but also, alterations in EOproduction as a response to N. ceranae infection it is an interesting clue to deeper understand theeffects of parasite-host-pesticide interaction on colony functioning.Fil: Porrini, Martín Pablo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Garrido, Paula Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Umpiérrez, María Laura. Universidad de la República; UruguayFil: Porrini, Leonardo Pablo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Cuniolo, Antonella. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Davyt, Belén. Universidad de la República; UruguayFil: González, Andrés. Universidad de la República; UruguayFil: Eguaras, Martin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Rossini, Carmen. Universidad de la República; Urugua

Sublethal effects of acaricides and Nosema ceranae infection on immune related gene expression in honeybees

Nosema ceranae is an obligate intracellular parasite and the etiologic agent of Nosemosis that affects honeybees. Beside the stress caused by this pathogen, honeybee colonies are exposed to pesticides under beekeeper intervention, such as acaricides to control Varroa mites. These compounds can accumulate at high concentrations in apicultural matrices. In this work, the effects of parasitosis/acaricide on genes involved in honeybee immunity and survival were evaluated. Nurse bees were infected with N. ceranae and/or were chronically treated with sublethal doses of coumaphos or tau-fluvalinate, the two most abundant pesticides recorded in productive hives. Our results demonstrate the following: (1) honeybee survival was not affected by any of the treatments; (2) parasite development was not altered by acaricide treatments; (3) coumaphos exposure decreased lysozyme expression; (4) N. ceranae reduced levels of vitellogenin transcripts independently of the presence of acaricides. However, combined effects among stressors on imagoes were not recorded. Sublethal doses of acaricides and their interaction with other ubiquitous parasites in colonies, extending the experimental time, are of particular interest in further research work.Fil: Garrido, Paula Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Cs. Exactas y Naturales. Centro de Investigación en Abejas Sociales; ArgentinaFil: Porrini, Martín Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Cs. Exactas y Naturales. Centro de Investigación en Abejas Sociales; ArgentinaFil: Antúnez, karina. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Branchiccela, Belén. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Martínez Noël, Giselle María Astrid. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnología; ArgentinaFil: Zunino, Pablo. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Salerno, Graciela Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnología; ArgentinaFil: Eguaras, Martin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Cs. Exactas y Naturales. Centro de Investigación en Abejas Sociales; ArgentinaFil: Ieno, Elena. Highland Statistics; Españ

Towards precision nutrition: a novel concept linking phytochemicals, immune response and honey bee health

The high annual losses of managed honey bees (Apis mellifera) has attracted intensive attention, and scientists have dedicated much effort trying to identify the stresses affecting bees. There are, however, no simple answers; rather, research suggests multifactorial effects. Several works have been reported highlighting the relationship between bees’ immunosuppression and the effects of malnutrition, parasites, pathogens, agrochemical and beekeeping pesticides exposure, forage dearth and cold stress. Here we analyze a possible connection between immunity-related signaling pathways that could be involved in the response to the stress resulted from Varroa-virus association and cold stress during winter. The analysis was made understanding the honey bee as a superorganism, where individuals are integrated and interacting within the colony, going from social to individual immune responses. We propose the term “Precision Nutrition” as a way to think and study bees’ nutrition in the search for key molecules which would be able to strengthen colonies’ responses to any or all of those stresses combined.Fil: Negri, Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Villalobos, Ethel. University of Hawaii at Manoa; Estados UnidosFil: Szawarski, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Damiani, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Gende, Liesel Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Garrido, Paula Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Maggi, Matías Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Quintana, Silvina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Lamattina, Lorenzo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Eguaras, Martin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentin

Tendencias en la apicultura y pérdida de colonias de abejas melíferas en América Latina

Over the past decade, several countries have carried out monitoring programs of managed honey bee colonies, which suggest beekeeping difficulties, with high colony loss rates all over the world. Although Latin America plays a major role in the global honey supply, information about trends in beekeeping activities and honey bee colony losses are lacking. Using the Food and Agriculture Organization of the United Nations (FAO) dataset and a synthesis of unpublished data of colony losses survey carried out over the last 7 years, we reveal a worrying situation of the beekeeping in this region. The Latin American trends in honey production and beehive numbers are drifting from the global pattern, and several high colony loss rates were registered in this region. These results reveal the presence of beekeeping difficulties in Latin America. However, the variability in methods of colony loss survey across initiatives prevent proper conclusion on loss rates. Efforts are needed to adapt, centralize and standardize methods to monitor honey bee health and colony losses across countries in Latin America, the main objective of the “colony losses” working group at the LatinAmerican Society for Bee Research, SOLATINA, a large-scale platform created in 2017 to coordinate bee research programs in Latin America.Durante la última década, varios países han llevado a cabo programas de monitoreo de colmenas de abejas melíferas, que sugieren dificultades en la apicultura relacionadas con altas tasas de pérdida de colonias al rededor del mundo. Aunque América Latina juega un papel importante en la producción mundial de miel, hay un vacío de información sobre la actividad apícola y las pérdidas de colonias en la región. Utilizando el conjunto de datos de la FAO y una síntesis de datos inéditos de encuestas sobre pérdidas de colonias realizada en los últimos siete años, revelamos una preocupante situación para la apicultura en esta región. Las tendencias latinoamericanas en la producción de miel y el número de colonias se desvían del patrón global, y se registran altas tasas de pérdidas de colonias en la región. Estos resultados revelan dificultades en el desarrollo apícola latinoamericano. Sin embargo, la variabilidad en los métodos de valoración de la pérdida de colonias en las diferentes iniciativas impide llegar a conclusiones definitivas sobre las tasas de pérdidas. Se necesitan esfuerzos para adaptar, centralizar y estandarizar los métodos de monitoreo de la salud de las abejas melíferas y las pérdidas de colonias en todos los países de América Latina. Esto constituye el principal objetivo del grupo de trabajo “Pérdida de colonias” de la Sociedad Latinoamericana de Investigación en Abejas, SOLATINA, una plataforma a gran escala creada en 2017 para coordinar los programas de investigación apícola en América Latina.Facultad de Ciencias Veterinaria

Effects of Synthetic Acaricides and <i>Nosema ceranae</i> (Microsporidia: Nosematidae) on Molecules Associated with Chemical Communication and Recognition in Honey Bees

Acaricides and the gut parasite Nosema ceranae are commonly present in most productive hives. Those stressors could be affecting key semiochemicals, which act as homeostasis regulators in Apis mellifera colonies, such as cuticular hydrocarbons (CHC) involved in social recognition and ethyl oleate (EO) which plays a role as primer pheromone in honey bees. Here we test the effect of amitraz, coumaphos, tau-fluvalinate and flumethrin, commonly applied to treat varroosis, on honey bee survival time, rate of food consumption, CHC profiles and EO production on N. ceranae-infected and non-infected honey bees. Di erent sublethal concentrations of amitraz, coumaphos, tau-fluvalinate and flumethrin were administered chronically in a syrup-based diet. After treatment, purified hole-body extracts were analyzed by gas chromatography coupled to mass spectrometry. While N. ceranae infection was also shown to decrease EO production affecting survival rates, acaricides showed no significant effect on this pheromone. As for the CHC, we found no changes in relation to the health status or consumption of acaricides. This absence of alteration in EO or CHC as response to acaricides ingestion or in combination with N. ceranae, suggests that worker honey bees exposed to those highly ubiquitous drugs are hardly differentiated by nest-mates. Having determined a synergic effect on mortality in worker bees exposed to coumaphos and Nosema infection but also, alterations in EO production as a response to N. ceranae infection it is an interesting clue to deeper understand the e ects of parasite-host-pesticide interaction on colony functioning.Instituto de Investigaciones Bioquímicas de La Plat