Italian Honey Research Articles

ERIC-PCR Genotyping of Paenibacillus larvae in Southern Italian Honey and Brood Combs

Given the considerable economic loss to beekeepers worldwide and the possible public health implications related to the presence of antibiotics in honey, an American Foulbrood (AFB) monitoring/prevention program for Paenibacillus larvae is regarded as essential. This study investigates the occurrence and distribution of P. larvae genotypes in honey and brood combs from Apulia (Italy). Genotyping of P. larvae isolates using ERIC-PCR generated a total of four different ERIC banding patterns (ERIC-A, ERIC-B, ERIC-C, ERIC-D), including fragments ranging from 200 to 3000bp. Considering that the genotype has an influence on P. larvae infections and multi-genotype infections of colonies or apiaries may increase the complexity of P. larvae infections by influencing the type and speed of the development of clinical symptoms, the findings of the present study could be helpful for training veterinarians, bee inspector's extension staff, and beekeepers, thus improving the detection of AFB infections in the field.

Characterization of the volatile profile of thistle honey using headspace solid-phase microextraction and gas chromatography–mass spectrometry

In this study, a headspace solid-phase microextraction method was developed for the characterization of the volatile fraction of thistle honey and compared with a dynamic headspace extraction method. A DVB/CAR/PDMS fibre was used. The effects of extraction time, equilibration time and salt addition on extraction yield were evaluated. The volatile fraction of seven Italian thistle honey samples was extracted under the optimized conditions and analyzed by gas chromatography–mass spectrometry. Characterization of the volatile profile was performed in terms of nature and relative amount of the extracted compounds. A total of 40 compounds, belonging to different chemical classes, were identified. The relative amounts of 16 compounds found in all the analyzed thistle honeys, i.e. nonanal, furfural, decanal, 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran, benzaldehyde, α-linalool, lilac aldehyde (isomer IV), hotrienol, phenylacetaldehyde, 4-oxoisophorone, benzyl alcohol, 2-phenylethanol, a not identified compound, octanoic acid, nonanoic acid and methyl anthranilate, were calculated and submitted to statistical analysis, in order to define for each compound a typical range. On the basis of the obtained data, a characteristic set of values was defined for thistle honey volatile fingerprint. The developed model proved to be effective in recognizing the botanical origin of thistle honey.

Seasonal population dynamics of small hive beetles, Aethina tumida Murray, in the south-eastern USA

SummaryThe population of small hive beetles, Aethina tumida (SHB), was monitored from 2005 to 2008 in colonies of Italian and Russian honey bees located near St. Gabriel, Louisiana, USA. SHB populations differed between honey bee strains (only in one site out of two), with Italian colonies supporting more beetles (7.45 ± 0.98 SHB per colony) than the Russian colonies (4.48 ± 0.51 SHB per colony). No difference between the two strains was observed at site 1 where the SHB population was generally low (Italian = 2.73 ± 0.36 SHB; Russian = 2.69 ± 0.57 SHB per colony). Our results also revealed that SHB populations varied throughout the year, with peak infestations observed in the autumn (September and November). SHB abundance was significantly correlated with the proportion of hot days, but not with the proportions of cool, dry, or humid days, or the percentage of days with rainfall. Our results suggest that in-hive autumn trapping of SHB in the south eastern USA may reduce springtime numbers of SHB.

Crystallization in “Tarassaco” Italian honey studied by DSC

The degree and rates of crystallization in honey stored at 5 °C, 10 °C, 15 °C, 20 °C and 25 °C were examined, with reference to rate enhancing and rate limiting factors of both thermodynamic and kinetic nature. Crystals of “Tarassaco” honey (from Taraxacum officinale Weber), mainly glucose monohydrate, were separated and purified from the residual amorphous phase and the enthalpy of melting was determined by DSC. The melting enthalpy resulted 108.39 ± 6.16 J g −1. The crystallization rates were 0.659, 0.755, 0.861, 0.815 and 0.593 g crystals × 100 g honey - 1 days - 1 at the cited temperatures. The water activity ( a w) increased from 0.593 in the liquid honey to 0.658, 0.652, 0.647, 0.639 and 0.640 after 222 days storage. The relationships among crystallization, supersaturation, glass transition temperatures ( T g), melting temperatures ( T m), difference ( T– T g), viscosity and a w are discussed.

Comparative Resistance of Russian and Italian Honey Bees (Hymenoptera: Apidae) to Small Hive Beetles (Coleoptera: Nitidulidae)

To compare resistance to small hive beetles (Coleoptera: Nitidulidae) between Russian and commercial Italian honey bees (Hymenoptera: Apidae), the numbers of invading beetles, their population levels through time and small hive beetle reproduction inside the colonies were monitored. We found that the genotype of queens introduced into nucleus colonies had no immediate effect on small hive beetle invasion. However, the influence of honey bee stock on small hive beetle invasion was pronounced once test bees populated the hives. In colonies deliberately freed from small hive beetle during each observation period, the average number of invading beetles was higher in the Italian colonies (29 +/- 5 beetles) than in the Russian honey bee colonies (16 +/- 3 beetles). A similar trend was observed in colonies that were allowed to be freely colonized by beetles throughout the experimental period (Italian, 11.46 +/- 1.35; Russian, 5.21 +/- 0.66 beetles). A linear regression analysis showed no relationships between the number of beetles in the colonies and adult bee population (r2 = 0.1034, P = 0.297), brood produced (r2 = 0.1488, P = 0.132), or amount of pollen (P = 0.1036, P = 0.295). There were more Italian colonies that supported small hive beetle reproduction than Russian colonies. Regardless of stock, the use of entrance reducers had a significant effect on the average number of small hive beetle (with reducer, 16 +/- 3; without reducer, 27 +/- 5 beetles). However, there was no effect on bee population (with reducer, 13.20 +/- 0.71; without reducer, 14.60 +/- 0.70 frames) or brood production (with reducer, 6.12 +/- 0.30; without reducer, 6.44 +/- 0.34 frames). Overall, Russian honey bees were more resistant to small hive beetle than Italian honey bees as indicated by fewer invading beetles, lower small hive beetle population through time, and lesser reproduction.

Characterisation of the phenolic and flavonoid fractions and antioxidant power of Italian honeys of different botanical origin

AbstractBACKGROUND: Twenty‐seven Italian honey samples of different floral origin were analysed for total phenolic and flavonoid contents by a spectrophotometric method and for antioxidant power and radical‐scavenging activity by the ferric‐reducing/antioxidant power (FRAP) and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) assays respectively. In addition, the phenolic and flavonoid profiles were analysed using high‐performance liquid chromatography with UV detection (HPLC‐UV).RESULTS: The results of this study showed that honey contains copious amounts of phenolics and flavonoids. HPLC‐UV analysis showed a similar qualitative polyphenolic profile for all honey samples analysed. The main difference among samples was in the contribution of individual analytes, which was affected by floral origin. Total phenolic and flavonoid contents varied from 60.50 to 276.04 mg gallic acid equivalent kg−1 and from 41.88 to 211.68 mg quercetin equivalent kg−1 respectively. The antioxidant capacity was high and differed widely among samples. The FRAP value varied from 1.265 to 4.396 mmol Fe2+ kg−1, while the radical‐scavenging activity expressed as DPPH‐IC50 varied from 7.08 to 64.09 mg mL−1. Correlations between the parameters analysed were found to be statistically significant (P < 0.05).CONCLUSION: The present study shows that honey contains high levels of phenolics and flavonoids and that the distribution of these compounds is influenced by the honey's floral origin. Copyright © 2009 Society of Chemical Industry

Ege Bölgesi’nde Muğla Ekotipi ve İtalyan Melezi Bal Arılarının Kimi Performans Özellikleri Bakımından Karşılaştırılması

Summary In this research, colony population growth, brood production, attractiveness, flight activity and honey production of Mugla ecotype and Italian cross honey bees have determined and evaluated with comparison in Aegean Region. Genotype effect did not found statistically important on colony population growth and brood production (P>0.05). Flight activity and honey yields of Italian cross honey bees determined more higher than Mugla ecotype whereas Mugla ecotype showed better performance than Italian cross for adaptation of environmental condition. At the end of the research, determining of performance characteristics and protecting of Mugla ecotype that of Aegean Region is suggested with making breeding programs.

Comparison of microsatellite DNA diversity among commercial queenbreeder stocks of Italian honey bees in the United States and Italy.

Comparison of microsatellite DNA diversity among commercial queenbreeder stocks of Italian honey bees in the United States and Italy.

Comparative reproduction of Varroa destructor in different types of Russian and Italian honey bee combs

Earlier studies showed that Russian honey bees support slow growth of varroa mite population. We studied whether or not comb type influenced varroa reproduction in both Russian and Italian honey bees, and whether Russian bees produced comb which inhibited varroa reproduction. The major differences found in this study concerned honey bee type. Overall, the Russian honey bees had lower (2.44 +/- 0.18%) levels of varroa infestation than Italian honey bees (7.20 +/- 0.60%). This decreased infestation resulted in part from a reduced number of viable female offspring per foundress in the Russian (0.85 +/- 0.04 female) compared to the Italian (1.23 +/- 0.04 females) honey bee colonies. In addition, there was an effect by the comb built by the Russian honey bee colonies that reduced varroa reproduction. When comparing combs having Russian or Italian colony origins, Russian honey bee colonies had more non-reproducing foundress mites and fewer viable female offspring in Russian honey bee comb. This difference did not occur in Italian colonies. The age of comb in this study had mixed effects. Older comb produced similar responses for six of the seven varroa infestation parameters measured. In colonies of Italian honey bees, the older comb (2001 dark) had fewer (1.13 +/- 0.07 females) viable female offspring per foundress than were found in the 2002 new (1.21 +/- 0.06 females) and 1980s new (1.36 +/- 0.08 females) combs. This difference did not occur with Russian honey bee colonies where the number of viable female offspring was low in all three types of combs. This study suggests that honey bee type largely influences growth of varroa mite population in a colony.

Comparison of microsatellite DNA diversity among commercial queen breeder stocks of Italian honey bees in the United States and Italy

SummaryDeclines in the numbers of breeder honey bee queens and the concomitant loss of genetic diversity could potentially result in inbreeding, and increased susceptibility to pests and diseases. Genetic diversity of commercial Italian bee colonies in the United States and Italy was assessed using six variable microsatellite DNA loci. Worker bees were sampled from colonies of queen breeders in both countries (USA, n = 18; Italy, n = 24). Overall, allelic richness (mean alleles/locus), gene diversity (heterozygosity), and FIS (inbreeding coefficient) did not differ between the two groups. A total of 48 alleles were present among all colonies. Sampled colonies from each country had a total of 38 alleles, although alleles were present that were unique to each group. There were a total of 10 unique alleles among USA bees and 10 among Italian bees. Estimates of the level of genetic differentiation based on different allele frequency patterns among the USA and Italian bees were measured with the population genetic parameter FST. These estimates showed that bees from the USA and Italy were measurably distinct relative to the frequencies of the microsatellite alleles present in samples from each country. Overall allelic diversity levels were sufficiently high indicating that inbreeding does not appear to be an immediate threat to existing honey bee populations.

Comparison of Parasitic Mites in Russian-Hybrid and Italian Honey Bee (Hymenoptera: Apidae) Colonies across Three Different Locations in North Carolina

The most economically important parasites of honey bee, Apis mellifera L. (Hymenoptera: Apidae), colonies are the parasitic mites Varroa destructor Anderson & Trueman and Acarapis woodi (Rennie). Research has shown that mite-tolerant stocks are effective means to reduce mite infestations within colonies, but it is unclear whether the stocks available commercially are viable means of mite control because they are likely to be genetic hybrids. We compared colonies of a standard commercial stock ("Italian") with those of a commercially purchased mite-tolerant stock ("Russian") for their levels of varroa and "tracheal" mites (A. woodi) over the course of 2 yr in three different geographic locations. We were unable to detect significant infestations of tracheal mites; thus, we were unable to adequately compare the stocks for their tolerance. In contrast, we found significant differences in the levels of varroa mites within and among colonies located across the three different study sites for both years. By the end of the first year, we found statistically significant differences between the stocks in varroa mite intensity (mites per adult bee), such that Russian-hybrid colonies tended to have a significantly lower proportion ofparasitized adult bees than Italian colonies. In the second year, we found statistically significant differences between the stocks in varroa mite load (daily mite drop), such that Russian-hybrid colonies tended to have lower total numbers of mites than Italian colonies. These findings suggest that beekeepers may benefit by incorporating commercially purchased mite-tolerant stocks into their existing integrated pest management programs.

Comparison of Parasitic Mites in Russian-Hybrid and Italian Honey Bee (Hymenoptera: Apidae) Colonies across Three Different Locations in North Carolina

Comparison of Parasitic Mites in Russian-Hybrid and Italian Honey Bee (Hymenoptera: Apidae) Colonies across Three Different Locations in North Carolina

Amplification of Three Unlinked Regions of Honey Bee (Hymenoptera: Apidae) DNA with Polymorphisms at High Frequencies in East European Subspecies

Abstract The growth rate (r) of Varroa destructor Anderson & Trueman (Acari: Varroidae) populations in Russian and Italian honey bee, Apis mellifera L., colonies was monitored from 2001 to 2003 in Baton Rouge, LA. Over this period, our results consistently showed lower mite growth in the Russian than in the Italian colonies. In 2001, instantaneous growth rates per week (r7) were r7 = 0.191 ± 0.011 for mites in Italian colonies and r7 = 0.137 ± 0.012 in Russian honey bees for 24.3 wk. These growth rates were equivalent to 159.1- and 61.6-fold increase, respectively. Divergence in r7 values also was observed in 2002 when Russian colonies supported a lower growth rate of r7 = 0.061 ± 0.016 (9.3-fold increase) than the Italian colonies (r7 = 0.122 ± 0.01 or a 31.7-fold increase) did after 26 wk. The lowest rate of r7 = 0.021 ± 0.011 (a 1.4-fold increase) was recorded for Russian honey bees in 2003, whereas the Italian bees in that year supported r7 = 0.145 ± 0.009 (an 18.9-fold increase) after 19 wk. This low...

Environmental and Genotypic Effects on Russian-Hybrid and Italian Honey Bee (Apis mellifera) (Hymenoptera: Apidae) Foraging Behavior

Both environment and genotype have a significant influence on the foraging behavior of honey bees (Apis mellifera). We compared the colony-level foraging behaviors of two honey bee stocks at three different sites by sampling 50 foragers each from 16 Russian-hybrid and 16 Italian colonies distributed among the Coastal Plain, Piedmont, and Mountain regions of North Carolina. We detected highly significant differences in foraging behavior among the different sites, but we found very few differences between the stocks. Moreover, there were very few environment–genotype interactions on foraging behavior, suggesting that the effect of genotype does not vary significantly depending on the environment in which it is located. These findings suggest that, while there are some notable differences between Russian-hybrid and Italian honey bees, the environment has a relatively larger impact on honey bee foraging behavior for these two stocks.

Environmental and Genotypic Effects on Russian-Hybrid and Italian Honey Bee (<I>Apis mellifera</I>) (Hymenoptera: Apidae) Foraging Behavior

Both environment and genotype have a signiÞcant insuence on the foraging behavior of honey bees (Apis mellifera). We compared the colony-level foraging behaviors of two honey bee stocks at three different sites by sampling 50 foragers each from 16 Russian-hybrid and 16 Italian colonies distributed among the Coastal Plain, Piedmont, and Mountain regions of North Carolina. We detected highly signiÞcant differences in foraging behavior among the different sites, but we found very few differences between the stocks. Moreover, there were very few environmentÐ genotype interactions on foraging behavior, suggesting that the effect of genotype does not vary signiÞcantly depending on the environment in which it is located. These Þndings suggest that, while there are some notable differences between Russian-hybrid and Italian honey bees, the environment has a relatively larger impact on honey bee foraging behavior for these two stocks.

Russian Honey Bee (Hymenoptera: Apidae) Colonies: <I>Acarapis woodi</I> (Acari: Tarsonemidae) Infestations and Overwintering Survival

Honey bee, Apis mellifera L. (Hymenoptera: Apidae), colonies infested by parasitic mites are more prone to suffer from a variety of stresses, including cold temperature. We evaluated the overwintering ability of candidate breeder lines of Russian honey bees, most of which are resistant to both Varroa destructor Anderson & Trueman and Acarapis woodi (Rennie), during 1999-2001. Our results indicate that Russian honey bee colonies (headed by original and supersedure queens) can successfully overwinter in the north, even during adverse weather conditions, owing to their frugal use of food stores and their resistance to tracheal mite infestations. In contrast, colonies of Italian honey bees consumed more food, had more mites, and lost more adult bees than Russian honey bees, even during unusually mild winter conditions.

Effect of a colour dimorphism on the flower constancy of honey bees and bumble bees

We assessed the flower constancy of Italian honey bees (Apis mellifera ligustica Spinelli, 1808) and bumble bees (Bombus impatiens Cresson, 1863) by presenting individual foragers with a mixed array of equally rewarding yellow and blue flowers after they were trained to visit each colour in succession. All honey bees showed a high degree of flower constancy to one colour and rarely visited the alternate colour, whereas most bumble bees indiscriminately visited both colours. Foraging rates (flowers visited per minute) and flower handling times did not differ between honey bee and bumble bee foragers; however, bumble bees tended to fly farther between consecutive flower visits and make fewer moves to nearest neighbouring flowers than honey bees. When bees were forced to specialize on one of two previously rewarding flower colours by depleting one colour of reward, honey bees required almost twice as many flower visits to specialize on the rewarding flower colour as bumble bees. Together, these results suggest that the relationship between individual flower constancy and colour differences is not a general behavioural phenomenon in honey and bumble bees, perhaps because of differences in the ability of each group to effectively manage multiple colours at the same time and location.

Supervised pattern recognition applied to the discrimination of the floral origin of six types of Italian honey samples

In this work a supervised chemometric approach to the discrimination of Italian honey samples from different floral origin is presented. The analytical data of 73 Italian honey samples from six varieties (chestnut, eucalyptus, heather, sulla, honeydew, and wildflower) have been processed by Linear Discriminant Analysis (LDA), using two different variable selection procedures (Fisher F-based and stepwise LDA). Three and two variables, respectively have been necessary to obtain a 100% predictive ability as evaluated by cross-validation. Successively, a class modeling approach has been followed, using UNEQ. The resulting models showed 100% sensitivity and specificity.

Varroa jacobsoni infestation of adult Africanized and Italian honey bees (Apis mellifera) in mixed colonies in Brazil

Different levels of infestation with the mite Varroa jacobsoni have been observed in the various Apis mellifera races. In general, bees of European races are more susceptible to the mite than African honey bees and their hybrids. In Brazil honey bee colonies are not treated against the mite, though apparently both climate and bee race influence the mite infestation. Six mixed colonies were made with Italian and Africanized honey bees. The percentage infestation by this parasite was found to be significantly lower in adult Africanized (1.69 ± 0.44) than Italian bees (2.79 ± 0.65). This ratio was similar to that found in Mexico, even though the Africanized bees tested there had not been in contact with varroa, compared to more than 20 years of the coexistence in Brazil. However, mean mite infestation in Brazil on both kinds of bees was only about a third of that found in Mexico.

Africanized honey bee response to differences in reward frequency

SUMMARYDifferences in predation pressure and floral resources exist among the endemic ranges of Apis mellifera subspecies. Those environmental differences should select for heterogeneity in forager flower fidelity among honey bee subspecies, particularly when reward frequency differences are associated with competing flower types. We tested that evolutionary model by examining the foraging behaviour of Africanized honey bees (AHB), and by comparing our observations with those recorded for Italian (A. m. ligustica) and Caucasian honey bees (A. m. caucasica). The response of AHB (A. m. scutel- lata hybrid/introgressant) to reward frequency differences among flower colours was examined using artificial flower patches. Each patch contained blue, white, and yellow flowers. When rewards offered by all three flower- morphs were identical, some foragers restricted visitation to blue and white flowers, while others showed fidelity to yellow flowers. Bees visiting blue and white flowers did not show a preference for either the blue or white colour morph under those conditions. However, forager behaviour changed when they were presented with different reward frequencies associated with the alternative flower colours. Bees frequenting blue and white flowers favoured blue when it offered a reward more frequently than white, and favoured white when the reverse was true. That behaviour occurred not only when the more frequently rewarding flower colour offered a higher harvest rate, but also when harvest rates obtained from all flower colours were equal. A change in flower colour fidelity involving yellow vs. blue and white flowers was observed only when reward frequency difference was linked to maximizing harvest rate. Those results contrast sharply to reported A. m. ligustica and A. m. caucasica honey bee behaviour: neither Italian nor Caucasian bees respond to reward frequency differences among flower colours, even between blue and white flowers.