Composition and antioxidant activity of honey from Africanized and stingless bees in Alagoas (Brazil): a multivariate analysis

The purpose of this study was to evaluate the antioxidant activity of honey from different entomological sources which were harvested in the dry season of 2008-2009 from distinct mesoregions of the State of Alagoas in the North East of Brazil. Honey produced by five different species of bees, even from the same region and season, showed a statistically significant difference (p <0.05) in the content of phenols, flavonoids and antioxidants, with higher levels of these compounds found in honey produced by Plebeia spp. and A. mellifera. Honey from stingless bees was quite different from that of A. mellifera, especially from the Plebeia spp. A dendrogram of the five species of bees showed the formation of 3 groups, one being formed by Apis mellifera, one by the genus Melipona (M. subnitida, M. quadrifasciata and M. scutellaris) and another formed by Plebeia spp.

The use of Open Reading frame ESTs (ORESTES) for analysis of the honey bee transcriptome

Abstract Background The ongoing efforts to sequence the honey bee genome require additional initiatives to define its transcriptome. Towards this end, we employed the Open Reading frame ESTs (ORESTES) strategy to generate profiles for the life cycle of Apis mellifera workers. Results Of the 5,021 ORESTES, 35.2% matched with previously deposited Apis ESTs. The analysis of the remaining sequences defined a set of putative orthologs whose majority had their best-match hits with Anopheles and Drosophila genes. CAP3 assembly of the Apis ORESTES with the already existing 15,500 Apis ESTs generated 3,408 contigs. BLASTX comparison of these contigs with protein sets of organisms representing distinct phylogenetic clades revealed a total of 1,629 contigs that Apis mellifera shares with different taxa. Most (41%) represent genes that are in common to all taxa, another 21% are shared between metazoans (Bilateria), and 16% are shared only within the Insecta clade. A set of 23 putative genes presented a best match with human genes, many of which encode factors related to cell signaling/signal transduction. 1,779 contigs (52%) did not match any known sequence. Applying a correction factor deduced from a parallel analysis performed with Drosophila melanogaster ORESTES, we estimate that approximately half of these no-match ESTs contigs (22%) should represent Apis-specific genes. Conclusions The versatile and cost-efficient ORESTES approach produced minilibraries for honey bee life cycle stages. Such information on central gene regions contributes to genome annotation and also lends itself to cross-transcriptome comparisons to reveal evolutionary trends in insect genomes.

Variation morphogeometrics of Africanized honey bees (Apis mellifera) in Brazil

The morphometrics of the honey bee Apis mellifera L., 1758 has been widely studied mainly because this species has great ecological importance, high adaptation capacity, wide distribution and capacity to effectively adapt to different regions. The current study aimed to investigate the morphometric variations of wings and pollen baskets of honey bees Apis mellifera scutellata Lepeletier, 1836 from the five regions in Brazil. We used geometric morphometrics to identify the existence of patterns of variations of shape and size in Africanized honey bees in Brazil 16 years after the classic study with this species, allowing a temporal and spatial comparative analysis using new technological resources to assess morphometrical data. Samples were collected in 14 locations in Brazil, covering the five geographical regions of the country. The shape analysis and multivariate analyses of the wing allowed to observe that there is a geographical pattern among the population of Apis mellifera in Brazil. The geographical variations may be attributed to the large territorial extension of the country in addition to the differences between the bioregions.

Effects of pesticides on honey bees (Apis mellifera L.): study of a specific route of exposure and evaluation of biochemical-physiological changes in the assessment of the pesticides toxicity

In this study, some important aspects of the relationship between honey bees (Apis mellifera L.) and pesticides have been investigated. In the first part of the research, the effects of the exposure of honey bees to neonicotinoids and fipronil contaminated dusts were analyzed. In fact, considerable amounts of these pesticides, employed for maize seed dressing treatments, may be dispersed during the sowing operations, thus representing a way of intoxication for honey bees. In particular, a specific way of exposure to this pesticides formulation, the indirect contact, was taken into account. To this aim, we conducted different experimentations, in laboratory, in semi-field and in open field conditions in order to assess the effects on mortality, foraging behaviour, colony development and capacity of orientation. The real dispersal of contaminated dusts was previously assessed in specific filed trials. In the second part, the impact of various pesticides (chemical and biological) on honey bee biochemical-physiological changes, was evaluated. Different ways and durations of exposure to the tested products were also employed. Three experimentations were performed, combining Bt spores and deltamethrin, Bt spores and fipronil, difenoconazole and deltamethrin. Several important enzymes (GST, ALP, SOD, CAT, G6PDH, GAPDH) were selected in order to test the pesticides induced variations in their activity. In particular, these enzymes are involved in different pathways of detoxification, oxidative stress defence and energetic metabolism. The results showed a significant effect on mortality of neonicotinoids and fipronil contaminated dusts, both in laboratory and in semi-field trials. However, no effects were evidenced in honey bees orientation capacity. The analysis of different biochemical indicators highlighted some interesting physiological variations that can be linked to the pesticide exposure. We therefore stress the attention on the possibility of using such a methodology as a novel toxicity endpoint in environmental risk assessment.

Sublethal effects of a common neonicotinoid pesticide, thiamethoxam, on honey bees: impact on locomotion and thermoregulation

Neonicotinoids have been pointed to as a factor responsible for the increased honey bee colony losses in the last decades. Many studies have investigated the effects of the first marketed neonicotinoid, imidacloprid, while fewer have focused on thiamethoxam. One recent study showed that sublethal doses of thiamethoxam lead to colony failure by decreasing forager homing flight success. We thus decided to investigate the mechanism which caused this phenomenon. Our hypothesis was that this effect was caused by impairment of forager locomotion abilities. Therefore we tested the effects of sublethal acute and chronic exposures to thiamethoxam on forager walking (Chapter 2) and flight (Chapter 3) performances. The acute treatment (1.34 ng/bee) affected walking locomotion firstly triggering hyperactivity (30 min post-treatment) and then impairing motor functioning (60 min post-treatment). 2-day continuous exposures to thiamethoxam (32.5, 45 ppb) elicited fewer effects on walking locomotion, however both exposure modes elicited an increased positive phototaxis. Similarly, in flight experiments, the single dose (1.34 ng/bee) elicited hyperactivity shortly after intoxication (increased flight duration and distance), while longer and continuous exposures (32.5, 45 ppb) impaired forager motor functions (decreased flight duration, distance, velocity). It is known that flight muscles temperature needs to be precisely regulated by bees during flight. Therefore, we further hypothesized that the impaired flight performances of neonicotinoid intoxicated bees were caused also by thermoregulation anomalies. We tested the effects that acute thiamethoxam exposures (0.2, 1, 2 ng/bee) elicit on forager thorax temperature (Chapter 4). Foragers treated with high doses exhibited hyperthermia or hypothermia when respectively exposed to high or low environmental temperatures. In summary, we show that sublethal doses of thiamethoxam affected forager walking and flight locomotion, phototaxis and thermoregulation. We also display the intricate mode of action of thiamethoxam which triggered, at different extents, inverse sublethal effects in relation to time and dose.

Virus infections and winter losses of honey bee colonies (Apis mellifera)

Apiculturists have recently been confronted with drastic and inexplicable winter losses of colonies, and virus infections may be involved. Here, we surveyed 337 Swiss honey bee colonies in the winter of 2005 and 2006 and categorized their health status as: 1. dead (= no or few live bees left); 2. weak (= dwindling, high mortality of adult bees); or 3. healthy (= normal overwintering colony). From each colony, pooled adult workers were analyzed for deformed wing virus (DWV), acute bee paralysis virus (ABPV), chronic bee paralysis virus (CBPV) and Kashmir bee virus (KBV). Neither KBV nor CBPV were found, but significantly higher ABPV and DWV infections were found in dead vs. weak vs. healthy colonies (except DWV in 2006 between weak and healthy). Moreover, ABPV and DWV loads were positively correlated with each other. This is the first report demonstrating statistically significant correlations between viruses associated with Varroa destructor and winter mortality.

Worldwide Diaspora of Aethina tumida (Coleoptera: Nitidulidae), a Nest Parasite of Honey Bees

Native to sub-Saharan Africa, Aethina tumida Murray (Coleoptera: Nitidulidae) is now an invasive pest of honey bee, Apis mellifera L., colonies in Australia and North America. Knowledge about the introduction (s) of this beetle from Africa into and among the current ranges will elucidate pest populations and invasion pathways and contribute to knowledge of how a parasite expands in new populations. We examined genetic variation in adult beetle samples from the United States, Australia, Canada, and Africa by sequencing a 912-base pair region of the mitochondrial DNA cytochrome c oxidase subunit I gene and screening 10 informative microsatellite loci. One Canadian introduction of small hive beetles can be traced to Australia, whereas the second introduction seems to have come from the United States. Beetles now resident in Australia were of a different African origin than were beetles in North America. North American beetles did not show covariance between two mitochondrial haplotypes and their microsatellite frequencies, suggesting that these beetles have a shared source despite having initial genetic structure within their introduced range. Excellent dispersal of beetles, aided in some cases by migratory beekeeping and the bee trade, seems to lead to panmixis in the introduced populations as well as in Africa.

Declines of managed honey bees and beekeepers in Europe

Growing evidence indicates that European managed honey bees are in decline, but information for Europe remains patchy and localized. Here we compile data from 18 European countries to assess trends in the number of honey bee colonies and beekeepers between 1965 and 2005. We found consistent declines in colony numbers in central European countries and some increases in Mediterranean countries. Beekeeper numbers have declined in all of the European countries examined. Our data support the view that honey bees are in decline at least in some regions, which is probably closely linked to the decreasing number of beekeepers. Our data on colony numbers and beekeepers must, however, be interpreted with caution due to different approaches and socioeconomic factors in the various countries, thereby limiting their comparability. We therefore make specific recommendations for standardized methodologies to be adopted at the national and global level to assist in the future monitoring of honey bees.

Localization of Deformed Wing Virus (DWV) in the Brains of Apis mellifera (European Honey Bees)

The purpose of the current research project is to design a successful in-situ hybridization to identify regions within the brains of honeybees where DWV replicates. The localization of the virus in the brains of the bees can draw a connection between CCDand DWV.In conclusion, these results demonstrate that in bees infected with DWV the virus replicates actively in very important regions of the brain, including neuropils that are responsible for vision and olfaction. This means that the virus could adversely affect the vision and olfaction of the honeybees making it difficult for bees to behave normally.