Characterization of preimaginal developmental stages in Africanized honey bee workers (Apis mellifera L)

The stages of preimaginal development of the Africanized worker honey bee (Apis mellifera L) were characterized. Body weight and head diameter were used as characters with which to differentiate among the first 4 instars, and additional traits such as apolysis, defecation and tibio-tarsal length of the hind legs were used to characterize the subdivision of the 5th and last instar. Pupal stages were determined on the basis of eye and thorax pigmentation. The duration of each stage was also determined from these characteristics. The post-embryonic development period of Africanized bees is ≈ 24 h shorter than that in Apis mellifera carnica, and 18 and 24 h longer than in African bees

Hybrid status of honey bee populations near the historic origin of Africanization in Brazil

Africanized honey bee populations are genetically heterogeneous across their extensive new world range. Over 35 years have elapsed since the introduction of A m scutellata to southeastern Brazil and we hypothesized that populations from this region should have achieved the highest degree of genetic equilibrium following the perturbation of introduction. We report here the results of a population genetic study of honey bees sampled near the origin of neotropical Africanization combining analyses of morphological, allozyme and mtDNA characters. Data from this study support previously reported allozyme frequency estimates and support the expectation that populations from this region are comparatively stable in genetic composition; and further, that significant polymorphism of European origin persists in the Africanized population of the region. Morphological and mtDNA data from these neotropical populations reveal the strong influence of the African race, A m scutellata. Apparent discordance among data sets from the several analytical methods reflects variation in selection and population size on the inheritance or persistence of such characters and indicates the importance of multiple character analysis

Analysis of the effects of climate variables on Apis mellifera pollen foraging performance

ABSTRACT Pollination services performed by bees are essential for the reproduction of a great part of flowering plants. The pollen collected by Apis mellifera while performing pollination (bee pollen), has been incorporated into the human diet for its favorable nutritional components. Around 1,500 tons of bee pollen are produced annually worldwide, especially in Spain, China, Australia, Argentina, and Brazil. Despite the importance of bee pollen within apiculture, little is known about the effects of climate variations on bee pollen collection and production. We monitored the pollen collection performance of 24 different honey bee colonies in different climate conditions within a period of one year. We then analyzed the statistical interaction among the number of worker bees returning with pollen loads and 12 climatic variables, to produce a predictive mixed linear model. The results obtained showed that 7 climatic variables were statistically correlated to the pollen collection observed: Maximum temperature of the day, minimum temperature of the day, dew point temperature, relative humidity, cloud cover, rainfall, and the date of the sample. This research brings information for the development of a more effective pollen productive system

Genetic characterization of a new Apis mellifera esterase

A new esterase, denoted esterase-1a (Est-1a), was first identified by starch gel electrophoresis of abdomen extracts from adult drones of Apis mellifera. This enzyme was developed only with 4-methylumbelliferyl esters and its inhibition properties suggest that it is an arylesterase. It does not contain reactive sulfhydryl groups and has a monomeric structure. A genetic variant (Est-1a92) was detected at an average frequency of 4.2% in drones collected from five apiaries. Genetic linkage studies showed no close linkage between the Est-1a locus and the genetic markers Est-6, Mdh-1 and Hk-1. Esterase-1 a activity was observed in the reproductive and digestive tracts of sexually mature drones, queens and egg-laying workers, suggesting its association with sexual maturation. In view of its presence in the egg and its restricted localization in the middle portion of the digestive tract (midgut), this enzyme may play a proteolytic role in early embryonic development

Differential performance of honey bee colonies selected for bee-pollen production through instrumental insemination and free-mating technique

ABSTRACT The use of bee-pollen as a nutritional supplement or as a production-enhancing agent in livestock has increased the demand for this product worldwide. Despite the current importance of this niche within the apiculture industry, few studies have addressed the pollen production. We tested the performance of free-mated (FM) and instrumentally inseminated queens (IQ) in order to establish the effect of different breeding systems on pollen production. The F1 generation of IQ queens produced 153.95±42.83g/day, showing a significant improvement on the pollen production (2.74 times) when compared to the parental generation (51.83±7.84g/day). The F1 generation of free-mated queens produced 100.07±8.23 g/day, which increased by 1.78 times when compared to the parental generation. Furthermore, we observed a statistically significant difference between the pollen production between colonies from the IQ and FM treatments. This study suggests that inseminated queens should be considered by beekeepers that aim to increase pollen production

Genetic differentiation estimated by isozymic analysis of Africanized honeybee populations from Brazil and from Central America

Adult Apis mellifera workers were electrophoretically examined in at least 7 enzyme loci. Five loci were found to exhibit polymorphism (Est-1, Est-3, PGM-1, HK-1 and MDH-1) in the Africanized bee populations from Brazil and from Central America (Costa Rica and Honduras). Genetic variation was not observed for Est-1 and HK-1 in the bee samples from Italy and Germany, and for PGM-1 in the Italian bee sample. Genotypic frequencies at the MDH-1 and HK-1 loci in the Honduras sample are in disagreement with that expected for Hardy-Weinberg equilibrium, suggesting an incipient process of mixture between pre-existing European bees in this country and the Africanized swarms that came from South America. Racial admixture estimates based on MDH-1 data indicate that the Africanization level of Central American honeybees is less than for bees from Southeast and Northern Brazil

Analysis of the effects of climate variables on Apis mellifera pollen foraging performance

<div><p>ABSTRACT Pollination services performed by bees are essential for the reproduction of a great part of flowering plants. The pollen collected by Apis mellifera while performing pollination (bee pollen), has been incorporated into the human diet for its favorable nutritional components. Around 1,500 tons of bee pollen are produced annually worldwide, especially in Spain, China, Australia, Argentina, and Brazil. Despite the importance of bee pollen within apiculture, little is known about the effects of climate variations on bee pollen collection and production. We monitored the pollen collection performance of 24 different honey bee colonies in different climate conditions within a period of one year. We then analyzed the statistical interaction among the number of worker bees returning with pollen loads and 12 climatic variables, to produce a predictive mixed linear model. The results obtained showed that 7 climatic variables were statistically correlated to the pollen collection observed: Maximum temperature of the day, minimum temperature of the day, dew point temperature, relative humidity, cloud cover, rainfall, and the date of the sample. This research brings information for the development of a more effective pollen productive system.</p></div

Effects of artepillin C on model membranes displaying liquid immiscibility

It has been hypothesized that the therapeutic effects of artepillin C, a natural compound derived from Brazilian green propolis, are likely related to its partition in the lipid bilayer component of biological membranes. To test this hypothesis, we investigated the effects of the major compound of green propolis, artepillin C, on model membranes (small and giant unilamelar vesicles) composed of ternary lipid mixtures containing cholesterol, which display liquid-ordered (lo) and liquid-disordered (ld) phase coexistence. Specifically, we explored potential changes in relevant membrane parameters upon addition of artepillin C presenting both neutral and deprotonated states by means of small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and confocal and multiphoton excitation fluorescence microscopy. Thermotropic analysis obtained from DSC experiments indicated a loss in the lipid cooperativity of lo phase at equilibrium conditions, while at similar conditions spontaneous formation of unilamellar vesicles from SAXS experiments showed that deprotonated artepillin C preferentially located at the surface of the membrane. Time-resolved experiments using fluorescence microscopy showed that at doses above 100 µM, artepillin C in its neutral state interacted with both liquid-ordered and liquid-disordered phases, inducing curvature stress and promoting dehydration at the membrane interface

Interaction of Artepillin C with model membranes

Green propolis, a mixture of beeswax and resinous compounds processed by Apis mellifera, displays several pharmacological properties. Artepillin C, the major compound in green propolis, consists of two prenylated groups bound to a phenyl group. Several studies have focused on the therapeutic effects of Artepillin C, but there is no evidence that it interacts with amphiphilic aggregates to mimic cell membranes. We have experimentally and computationally examined the interaction between Artepillin C and model membranes composed of dimyristoylphosphatidylcholine (DMPC) because phosphatidylcholine (PC) is one of the most abundant phospholipids in eukaryotic cell membranes. PC is located in both outer and inner leaflets and has been used as a simplified membrane model and a non-specific target to study the action of amphiphilic molecules with therapeutic effects. Experimental results indicated that Artepillin C adsorbed onto the DMPC monolayers. Its presence in the lipid suspension pointed to an increased tendency toward unilamellar vesicles and to decreased bilayer thickness. Artepillin C caused point defects in the lipid structure, which eliminated the ripple phase and the pre-transition in thermotropic chain melting. According to molecular dynamics (MD) simulations, (1) Artepillin C aggregated in the aqueous phase before it entered the bilayer; (2) Artepillin C was oriented along the direction normal to the surface; (3) the negatively charged group on Artepillin C was accommodated in the polar region of the membrane; and (4) thinner regions emerged around the Artepillin C molecules. These results help an understanding of the molecular mechanisms underlying the biological action of propolis

Isolation And Characterization Of Microsatellite Markers From The Stingless Bee Nannotrigona Testaceicornis

Conservation of natural populations and handling of breeding programs would benefit from the availability of molecular markers. Stingless bees are one of the most important pollinators in several ecosystems. Thus, seventeen microsatellite markers were developed from an enriched genomic library of Nannotrigona testaceicornis. They were characterized using 50 samples. The expected and observed heterozygosities ranged from 0.59 to 0.89 and from 0.39 to 0.79, respectively. These markers will contribute to advance researches on the genetic conservation, characterization and preservation of the Brazilian native bees. © Springer Science+Business Media B.V. 2009.119799Billotte, N., Lagoda, P.J.L., Risterucci, A.M., Baurens, F.C., Microsatellite-enriched libraries: Applied methodology for the development of SSR markers in tropical crops (1999) Fruits, 54, pp. 277-288Creste, S., Tulmann-Neto, A., Figueira, A., Detection of single sequence repeat polymorphism in denaturing polyacrylamide sequencing gels by silver staining (2001) Plant Mol Biol Report, 19, pp. 1-8Francisco, F.O., Silvestre, D., Arias, M.C., Mitochondrial DNA characterization of five species of Plebeia (Apidae: Meliponini): RFLP and restriction map (2001) Apidologie, 32, pp. 323-332Green, C.L., Franck, C., Oldroyd, B.P., Characterization of microsatellite loci for Trigona carbonaria, a stingless bee endemic to Australia (2001) Mol Ecol Notes, 1, pp. 89-92Kerr, W.E., Carvalho, G.A., Nascimento, V.A., (1996) Abelha Uruçu, , Biologia, manejo e conservação, Fundação Acangaú, Belo HorizonteNei, M., Estimation of average heterozygosity and genetic distance from a small number of individuals (1978) Genetics, 89, pp. 583-590Paxton, R.J., Weißschuh, N., Quezada-Euan, J.J.G., Characterization of dinucleotide microsatellite loci for stingless bees (1999) Mol Ecol, 8, pp. 685-702Peters, J.M., Queller, D.C., Imperatriz-Fonseca, V.L., Strassmann, J.E., Microsatellite loci for stingless bees (1998) Mol Ecol, 7, pp. 783-792Raymond, M., Rousset, F., GENEPOP (version 1.2): Population genetics software for exact tests and ecumenicism (1995) J Hered, 86, pp. 248-249Rozen, S., Skaletsky, H.J., PRIMER 3 on the WWW for general users and for biologist programmers (2000) Bioinformatics Methods and Protocols: Methods in Molecular Biology, pp. 365-386. , In: Krawetz S, Misener S (eds), Humana Press, Totowa, NJSambrook, J., Fritsch, E.F., Maniatis, T., (1989) Molecular Cloning: A Laboratory Manual, , 2nd edn. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NYvan Oosterhout, C., Hutchinson, W.F., Wills, D.P.M., Shipley, P., MICRO-CHECKER: Software for identifying and correcting genotyping errors in microsatellite data (2004) Mol Ecol Notes, 4, pp. 535-53