First large-scale study reveals important losses of managed honey bee and stingless bee colonies in Latin America.

Over the last quarter century, increasing honey bee colony losses motivated standardized large-scale surveys of managed honey bees (Apis mellifera), particularly in Europe and the United States. Here we present the first large-scale standardized survey of colony losses of managed honey bees and stingless bees across Latin America. Overall, 1736 beekeepers and 165 meliponiculturists participated in the 2-year survey (2016-2017 and 2017-2018). On average, 30.4% of honey bee colonies and 39.6% of stingless bee colonies were lost per year across the region. Summer losses were higher than winter losses in stingless bees (30.9% and 22.2%, respectively) but not in honey bees (18.8% and 20.6%, respectively). Colony loss increased with operation size during the summer in both honey bees and stingless bees and decreased with operation size during the winter in stingless bees. Furthermore, losses differed significantly between countries and across years for both beekeepers and meliponiculturists. Overall, winter losses of honey bee colonies in Latin America (20.6%) position this region between Europe (12.5%) and the United States (40.4%). These results highlight the magnitude of bee colony losses occurring in the region and suggest difficulties in maintaining overall colony health and economic survival for beekeepers and meliponiculturists.

Genetic variability of the honey bee mite, Varroa destructor, from a humid continental climatic region of Canada, and temperate and tropical climatic regions of Mexico.

Varroa destructor is a damaging mite of Western honey bees (Apis mellifera). Genetic variability of the mite in different regions of the world could be related to the movement of infested bees or other factors, such as climate. In this study, V. destructor samples were collected from tropical and temperate climate regions of Mexico, and a humid continental climate region of Canada. COX-1 AFLPs showed that all the mites were the Korean haplotype. Four microsatellites revealed nine haplogroups from the continental climate region of Canada, compared to three haplogroups from the tropical and temperate climate regions of Mexico. CytII-ATP sequences showed seven haplogroups from the humid continental climate region vs. two haplogroups from the temperate region and one haplogroup from the tropical region. CytB sequences revealed seven haplogroups from Canada vs. three from Mexico. A comparison of the cytB sequences of the samples from Canada and Mexico to those from a worldwide collection showed that one sequence, designated the cytB1 type, predominated, comprising 57% of the 86 sequences; it clustered with similar sequences that comprised 80% of the sequences, designated family A. CytB1 was predominant in Mexico, but not in Canada. The other 20% of sequences were in families B and C, and all those samples originated from East and Southeast Asia. The microsatellite, cytII-ATP, and cytB markers, all showed higher variability in mites collected in Canada than in Mexico, which could be related to the cooler climate or an earlier invasion and/or multiple mite invasions in Canada.

Prevalence of Adult Honey Bee (Apis mellifera L.) Pests and Pathogens in the Five Beekeeping Regions of Mexico.

Mexico is a major honey producer, but not much information exists about the health status of honey bees (Apis mellifera L.) in the country. This study was conducted to determine the sanitary status of adult honey bees in Mexico's five beekeeping regions. Samples from 369 apiaries were diagnosed to identify pathogens such as Varroa destructor, which was quantified, Acarapis woodi, Nosema spp., and five viruses. Colonies were also inspected for the presence of the small hive beetle (SHB), Aethina tumida. Varroa destructor was found in 83.5% of the apiaries, with the Pacific Coast region having the highest prevalence (>95%) and rates (4.5% ± 0.6). Acarapis woodi was detected in only one apiary from the Pacific Coast, whereas Nosema spp. were prevalent in 48.5% of the apiaries, with the highest and lowest frequencies in the Yucatan Peninsula and North regions (64.6% and 10.2%, respectively). For viruses, deformed wing virus (DWV) was detected in 26.1% of the apiaries, with the highest frequency in the Pacific Coast region (44.7%). Israeli acute paralysis virus (IAPV) was diagnosed in 3.2% of the samples and sacbrood bee virus (SBV) in 23.3% of them, with the highest frequency in the High Plateau region (36.4%). Chronic bee paralysis and Kashmir bee viruses were not detected. SHB prevalence was 25.2% nationwide, with the highest frequency in the Yucatan Peninsula (39.2%). This study shows that the most common parasites of adult honey bees in Mexico are V. destructor and Nosema spp., and that the most prevalent virus is DWV, whereas SHB is highly prevalent in the Yucatan Peninsula. This information could be useful to design disease control strategies for honey bee colonies in different regions of Mexico.

Genotype, but Not Climate, Affects the Resistance of Honey Bees (Apis mellifera) to Viral Infections and to the Mite Varroa destructor.

This study was conducted to analyze the effect of genotype and climate on the resistance of honey bee (Apis mellifera) colonies to parasitic and viral diseases. The prevalence and intensity of parasitism by Varroa destructor, or infection by Nosema spp., and four honey bee viruses were determined in 365 colonies of predominantly European or African ancestry (descendants of A. m. scutellata) in subtropical and temperate regions of Mexico. Varroa destructor was the most prevalent parasite (95%), whilst N. ceranae was the least prevalent parasite (15%). Deformed wing virus (DWV) and black queen cell virus (BQCV) were the only viruses detected, at frequencies of 38% and 66%, respectively. Varroa destructor was significantly more prevalent in colonies of European ancestry (p < 0.05), and the intensity of parasitism by V. destructor or infection by DWV and BQCV was also significantly higher in colonies of European descent than in African descent colonies (p < 0.01), although no genotype−parasite associations were found for N. ceranae. Additionally, significant and positive correlations were found between V. destructor and DWV levels, and the abundance of these pathogens was negatively correlated with the African ancestry of colonies (p < 0.01). However, there were no significant effects of environment on parasitism or infection intensity for the colonies of both genotypes. Therefore, it is concluded that the genotype of honey bee colonies, but not climate, influences their resistance to DWV, BQCV, and V. destructor.

Impact of sublethal exposure to synthetic and natural acaricides on honey bee (Apis mellifera) memory and expression of genes related to memory.

Acaricides are used by beekeepers in honey bee (Apis mellifera L.) colonies to control parasitic mites, but may also have adverse effects to honey bees. In this study, five commonly used acaricides were tested for their sublethal effects on memory and expression of neural-related genes in honey bees. Memory measured with the proboscis extension reflex (PER) assay was significantly reduced by topical treatment of bees with a single LD05 dose of formic acid at 2 and 24 h post treatment (hpt). However, tau-fluvalinate, amitraz, coumaphos, and formic acid, but not thymol, resulted in memory loss at 48 hpt. The LD05 doses of the acraricides did not affect expression of neuroligin-1, related to memory, or expression of major royal jelly protein-1, related to both memory and development, although expression of both genes was affected at LD50 doses. The LD05 doses of thymol, formic acid, amitraz and coumaphos increased defensin-1 expression, which is related to both memory and immunity. The effect of thymol, however, may have been due to its impact on the immune response rather than memory. This study demonstrates that acaricides vary in their effects on bee's memory, and that the widely used acaricide, formic acid, is particularly damaging.

Impact of Varroa destructor and deformed wing virus on emergence, cellular immunity, wing integrity and survivorship of Africanized honey bees in Mexico.

The ectoparasitic mite Varroa destructor is the primary health problem of honey bees (Apis mellifera) worldwide. Africanized honey bees in Brazil have demonstrated tolerance to the mite, but there is controversy about the degree of mite tolerance of Africanized bees in other countries. This study was conducted to quantify the effect of V. destructor parasitism on emergence, hemocyte concentration, wing integrity and longevity of Africanized honey bees in Mexico. Africanized bee brood were artificially infested with V. destructor mites and held in an incubator until emergence as adults and compared to non-infested controls. Deformed wing virus (DWV) presence was determined in the mites used to infest the bees. After emergence, the bees were maintained in an incubator to determine survivorship. The percentage of worker bees that emerged from parasitized cells (69%) was significantly lower than that of bees emerged from non-infested cells (96%). Newly-emerged parasitized bees had a significantly lower concentration of hemocytes in the hemolymph than non-parasitized bees. Additionally, the proportion of bees with deformed wings that emerged from V. destructor-parasitized cells was significantly higher (54%) than that of the control group (0%). The mean survival time of bees that emerged from infested and non-infested cells was 8.5 ±â€¯0.3 and 14.4 ±â€¯0.4 days, respectively, and the difference was significant. We conclude that V. destructor parasitism and DWV infections kill, cause deformities and inhibit cellular immunity in developing Africanized honey bees, and significantly reduce the lifespan of adult bees in Mexico. These results suggest that the tolerance of Africanized bees to V. destructor is related to adult bee mechanisms.

Nosema ceranae is an old resident of honey bee (Apis mellifera) colonies in Mexico, causing infection levels of one million spores per bee or higher during summer and fall.

This study was conducted to identify Nosema spp. and to determine their infection levels in honey bee (Apis mellifera) samples collected in Mexico in 1995-1996. Samples of historical surveys from different countries are of particular interest to support or challenge the hypothesis that the microsporidium Nosema ceranae is a new parasite of A. mellifera that has recently dispersed across the world. We demonstrate that N. ceranae has parasitized honey bees in Mexico since at least 1995 and that the infection levels of this parasite during summer and fall, exceed the threshold at which treatment of honey bee colonies is recommended.

Varroa destructor (Mesostigmata: Varroidae) Parasitism and Climate Differentially Influence the Prevalence, Levels, and Overt Infections of Deformed Wing Virus in Honey Bees (Hymenoptera: Apidae).

The prevalence and loads of deformed wing virus (DWV) between honey bee (Apis mellifera L.) colonies from a tropical and a temperate environment were compared. The interaction between these environments and the mite Varroa destructor in relation to DWV prevalence, levels, and overt infections, was also analyzed. V. destructor rates were determined, and samples of mites, adult bees, brood parasitized with varroa mites and brood not infested by mites were analyzed. DWV was detected in 100% of the mites and its prevalence and loads in honey bees were significantly higher in colonies from the temperate climate than in colonies from the tropical climate. Significant interactions were found between climate and type of sample, with the highest levels of DWV found in varroa-parasitized brood from temperate climate colonies. Additionally, overt infections were observed only in the temperate climate. Varroa parasitism and DWV loads in bees from colonies with overt infections were significantly higher than in bees from colonies with covert infections. These results suggest that interactions between climate, V. destructor, and possibly other factors, may play a significant role in the prevalence and levels of DWV in honey bee colonies, as well as in the development of overt infections. Several hypotheses are discussed to explain these results.

Analysis of volatile components from Melipona beecheii geopropolis from Southeast Mexico by headspace solid-phase microextraction.

A head space solid-phase microextraction method combined with gas chromatography-mass spectrometry was developed and optimised to extract and analyse volatile compounds of Melipona beecheii geopropolis. Seventy-three constituents were identified using this technique in the sample of geopropolis collected. The main compounds detected include ß-fenchene (14.53-15.45%), styrene (8.72-9.98%), benzaldehyde (7.44-7.82%) and the most relevant volatile components presents at high level in the geopropolis were terpenoids (58.17%).

Differential responses of Africanized and European honey bees (Apis mellifera) to viral replication following mechanical transmission or Varroa destructor parasitism.

For the first time, adults and brood of Africanized and European honey bees (Apis mellifera) were compared for relative virus levels over 48 h following Varroa destructor parasitism or injection of V. destructor homogenate. Rates of increase of deformed wing virus (DWV) for Africanized versus European bees were temporarily lowered for 12h with parasitism and sustainably lowered over the entire experiment (48 h) with homogenate injection in adults. The rates were also temporarily lowered for 24h with parasitism but were not affected by homogenate injection in brood. Rates of increase of black queen cell virus (BQCV) for Africanized versus European bees were similar with parasitism but sustainably lowered over the entire experiment with homogenate injection in adults and were similar for parasitism and homogenate injection in brood. Analyses of sac brood bee virus and Israeli acute paralysis virus were limited as detection did not occur after both homogenate injection and parasitism treatment, or levels were not significantly higher than those following control buffer injection. Lower rates of replication of DWV and BQCV in Africanized bees shows that they may have greater viral resistance, at least early after treatment.

Colonización, impacto y control de las abejas melíferas africanizadas en México / Colonization, impact and control of Africanized honey bees in Mexico

This review article describes the colonization process and the replacement of European honey bee populations by Africanized bees, as well as the biological characteristics that have given Africanized bees advantages for their colonizing success, and a discussion on their impact, control, and perspectives for the Mexican beekeeping industry, taking into consideration the beekeepers' point of view with regard to their management and culture in comparison with European bees.

En este trabajo recapitulativo se describe el proceso de colonización y reemplazo de las poblaciones de abejas melíferas europeas por africanizadas, así como las características biológicas que han dado ventajas a las abejas africanizadas para su éxito colonizador y una discusión sobre su impacto, control y perspectivas para la apicultura mexicana, abordando el punto de vista de los apicultores respecto a su manejo y explotación en comparación con abejas europeas.

Estudio comparativo de tres pruebas para evaluar el comportamiento higiénico en colonias de abejas (Apis mellifera L.) / Comparative study of three assays to evaluate hygienic behavior in honey bee (Apis mellifera L.) colonies

The discriminatory capacity, cost and practicality of three assays to measure hygienic behavior in 60 honey bee colonies were compared in a first experiment. Capped worker brood of these colonies were killed with an insect pin (P), frozen in a freezer at -18°C (CC) and with liquid nitrogen at -195°C (CN2). The percentage of brood removed by the bees was recorded 24 h after being killed. Since the P assay showed a low discriminatory capacity, an additional experiment with 50 colonies was performed, reducing the evaluation time to 8 h and verifying the influence of body fluids and odors released by the pin-killed brood. Colonies were significantly more hygienic (P < 0.01) with the P assay (88%) than with the CC (69%) and CN2 (65%) assays. There were significant correlations among assays (r > 0.54, P < 0.01) and between replicates within assays (r > 0.37, P < 0.01). Variation among colonies was greater with the CN2 and CC assays than with the P assay. The P assay was the least expensive and easiest to apply (6.59 pesos, 0.58 dollars per colony), but showed the lowest discriminatory capacity, that could not be enhanced even though the time of evaluation was reduced. This could have been caused by the strong stimulus from odors and haemolymph released from the pinkilled brood. The CN2 and the CC assays showed a high discriminatory capacity, but the former was more expensive (14.80 pesos, 1.31 dollars) and the least practical. The CC assay was the second least expensive (10.15 pesos, 0.90 dollars) and practical. The application of either freeze assays is recommended for screening hygienic behavior in honey bees because of their reliability.

Se comparó la capacidad discriminatoria, costo y facilidad de aplicación de tres pruebas para medir el comportamiento higiénico en 60 colonias de abejas melíferas en un primer experimento. Las crías operculadas de estas colonias fueron sacrificadas al puncionarlas con un alfiler entomológico (P), y congelarlas en congelador a -18°C (CC) con nitrógeno líquido a -195° C (CN2). Se determinó el porcentaje de crías removidas por las abejas 24 h después de que fueron sacrificadas. Como consecuencia de la poca discriminación entre colonias inicialmente encontrada con la prueba P, se realizó un experimento adicional con 50 colonias, reduciendo el tiempo de lectura a 8 h y se verificó el efecto producido por la emanación de olores y fluidos de las crías sacrificadas. Las colonias fueron significativamente más higiénicas (P < 0.01) con la prueba P (88%), en comparación con la de CC (69%) y CN2 (65%). Se encontraron correlaciones significativas entre pruebas (r > 0.54, P < 0.01) y entre repeticiones dentro de pruebas (r > 0.37, P < 0.01). La variación entre colonias fue mayor con las pruebas CN2 y CC que con la P. La prueba P fue la más económica y práctica de aplicar (6.59 pesos, 0.58 dólares, por colonia), pero mostró menor capacidad discriminatoria, que no se incrementó aun cuando se redujo el tiempo de lectura. Este resultado pudo deberse al fuerte estímulo provocado por olores y hemolinfa emanados de las crías sacrificadas. Las pruebas CN2 y CC mostraron alta capacidad discriminatoria, pero la primera fue más cara (14.80 pesos, 1.31 dólares) y la menos práctica. La prueba CC fue la segunda más económica (10.15 pesos, 0.90 dólares) y práctica. Se recomienda aplicar cualquiera de las pruebas de congelación para medir el comportamiento higiénico de colonias de abejas melíferas por su confiabilidad.