Georgios Goras

Ranking pollen from bee plants according to their protein contribution to honey bees

The existing literature classifies bee pollen as “excellent” or “poor” according to protein content. In this research, we ranked bee pollen according to its contribution to bee nutrition, taking into consideration the seasonal variation. We found that the richness in protein content of each single taxon alone is not enough to classify it, as a “good” pollen source, and seasonal variation in vegetation and colony needs should be taken into account. In many cases, bees collected more pollen from plants poorer in protein, which were in total more beneficial to the colony compared to pollen rich in protein, but collected in smaller amounts. We concluded that the amount of the collected pollen was the most important factor and this is relative to the population of the plants at the surrounding area, the flowering period, and the season. The attractiveness of pollen, as indicated by the amount of pollen collected by the bees, was not correlated to the protein content of different taxa. Bees collected pollen from a large number of taxa, but only few of those contributed significantly to their nutritional requirements. We found that only 14 out of 46 pollen taxa included the 88.8% of the total proteins that were available for bees. The crude protein of these “selected” pollen sources ranged from 13.9 to 25.5%. Pollen from plants blooming in spring had higher protein content (20–24.7%) than those from summer (15.1–19.9%) and autumn (19.3–23.1%). The great amount of pollen that honey bees collected in spring and its richness in proteins could explain the strong growth of brood and population during this period.

Pollen analysis as a means to determine the geographical origin of royal jelly

In this study we investigated the use of pollen analysis as a method to determine the geographical origin of royal jelly. We recorded the pollen flora sampled by bees using pollen traps for two consecutive years and we also collected and examined royal jelly samples from the same apiary. For royal jelly production, bees mainly used the freshly collected pollen. All major pollen types that were recorded in the area using pollen traps were also detected in the royal jelly samples. Thus, pollen analysis can be used as a method to determine the geographical origin of royal jelly.

Impact of honeybee (Apis mellifera L.) density on wild bee foraging behaviour

Abstract Honey bees are globally regarded as important crop pollinators and are also valued for their honey production. They have been introduced on an almost worldwide scale. During recent years, however, several studies argue their possible competition with unmanaged pollinators. Here we examine the possible effects of honey bees on the foraging behaviour of wild bees on Cistus creticus flowers in Northern Greece. We gradually introduced one, five, and eight honey-bee hives per site, each containing ca. 20,000 workers. The visitation frequency and visit duration of wild bees before and after the beehive introductions were measured by flower observation. While the visitation frequencies of wild bees were unaffected, the average time wild bees spent on C. creticus increased with the introduction of the honey-bee hives. Although competition between honey bees and wild bees is often expected, we did not find any clear evidence for significant effects even in honey-bee densities much higher than the European-wide average of 3.1 colonies/km2.

Nontarget Effects of Aerial Mosquito Adulticiding with Water-Based Unsynergized Pyrethroids on Honey Bees and other Beneficial Insects in an Agricultural Ecosystem of North Greece

ABSTRACT We assessed the nontarget effects of ultra-low-volume (ULV) aerial adulticiding with two new water-based, unsynergized pyrethroid formulations, Aqua-K-Othrine (FFAST antievaporant technology, 2% deltamethrin) and Pesguard S102 (10% d-phenothrin). A helicopter with GPS navigation technology was used. One application rate was tested per formulation that corresponded to 1.00 g (AI)/ha of deltamethrin and 7.50 g (AI)/ha of d-phenothrin. Three beneficial nontarget organisms were used: honey bees (domesticated hives), family Apidae (Apis mellifera L.); mealybug destroyers, family Coccinellidae (Cryptolaemus montrouzieri Mulsant); and green lacewings, family Chrysopidae (Chrysoperla carnea (Stephens)). No significant nontarget mortalities were observed. No bees exhibited signs of sublethal exposure to insecticides. Beehives exposed to the insecticidal applications remained healthy and productive, performed as well as the control hives and increased in weight (25–30%), in adult bee population (14–18%), and in brood population (15–19%).

Legislation of honey criteria and standards

Differences between European legislation and revised Codex Alimentarius standards exist, and refer to the definition, the claim of the country of origin, honey of low enzymes and the adoption of Baker’s honey. Furthermore, different countries maintain dated quality criteria that do not coincide with the provisions of Codex or EU directives. The parameters that vary are mainly the moisture content, HMF, diastase activity, electrical conductivity, sugars and the microscopical justification. The necessity to adopt national rules is imposed mainly by the absence of provisions regarding the characteristics of monofloral honey, the declaration of the geographical origin of the product, the natural deviation of different types of honey and the quality rating of domestic honey. To address the problem that exists in international legislation regarding honey, we propose adopting minimum requirements as mandatory for all countries that produce, import or export honey.

The determination of the botanical origin in honeys with over-represented pollen: combination of melissopalynological, sensory and physicochemical analysis

BACKGROUND Pollen analysis of honey is the basic method for the determination of its botanical origin. However, the presence of over-represented pollen in honeys may lead the analysis to false results. This can be more severe if this pollen is present in unifloral under-represented honeys of commercial importance (e.g. thyme honey). In the present study, we investigated the abundance of over-represented pollen grains on several quality characteristics in honey samples. In particular, we mixed honeys characterised as over-represented, specifically chestnut and eucalyptus, with thyme honeys in different analogies, and we also analysed the melissopalynological, organoleptic, physicochemical (water content, electrical conductivity, colour) and volatile characteristics of the blends. RESULTS The most sensitive parameters were the microscopic characteristics, followed by the organoleptic ones. Blends of thyme honey with an originally low percentage of thyme pollen were the most influenced and could not be characterised as unifloral regarding their melissopalynological characteristics, even when they were mixed with small quantities of honeys with over-represented pollen (i.e. 5%). CONCLUSION The present study confirms that, in the case of presence of over-represented pollen in honeys, pollen analysis alone cannot give trustworthy results for the determination of the botanical origin, even though their exclusion during pollen analysis, when they are present in percentages of up to 30%, could provide more accurate results. Consequently, pollen analysis should also be combined with the other analyses, especially in honeys with under-represented and over-represented pollens, to give safer results for the botanical characterisation of honeys.

Melissopalynological analysis of royal jelly from Greece

Abstract Microscopic analysis of 82 royal jelly samples obtained from several locations in Greece was carried out in order to study the pollen spectrum of Greek royal jelly. The analysis recorded over 60 taxa. The abundance of each pollen type varied among the areas and the samples. The most frequent pollen types found in the samples were Brassicaceae, Olea europaea, Eucalyptus, Trifolium, Rubus, Carduus-type, Hypericum, Daucus-type and Cistus. The majority of the pollen types found in the royal jelly samples were also found at the pollen flora around the apiaries.

Investigating the Effect of Supplementary Feeding on Carbohydrate Composition and Quantity of Royal Jelly

One of the main practices followed by beekeepers during the production of royal jelly (RJ) is the artificial sugar feeding. In this study, the effect of carbohydrate supplementary feeding on the composition of the three main sugars (fructose, glucose, sucrose) and on the final quantity of the product was explored using one-way ANOVA and non-parametric tests. Also, the correlations among the parameters were examined. The average yield per colony for non-supplemented colonies (Group A) was 12.8 g, while the average content of fructose, glucose and sucrose was 4.32%, 3.78%, and 0.04%, respectively. For the colonies fed at the grafting day one time (Group B), these values were 12.76 g, 3.11%, 3.19% and 3.71%, and for the colonies fed from the insertion until the collection day (Group C), 12.81 g, 3.05%, 3.12% and 3.54% respectively. It should also be noted that the sucrose content in all samples from supplemented colonies was found greater than 1.97%. The statistical tests highlighted the impact of artificial feeding on fructose and glucose contents, while the produced quantity remained uninfluenced. Finally, the Spearman (rho) coefficient test showed statistically significantly negative correlation between the monosaccharides (fructose, glucose) and sucrose.

Rearing Drones in Queen Cells of Apis mellifera Honey Bees

Abstract We investigated the rearing of drone larvae grafted in queen cells. From the 1200 drone larvae that were grafted during spring and autumn, 875 were accepted (72.9%) and reared as queens. Drone larvae in false queen cells received royal jelly of the same composition and of the same amounts as queen larvae. Workers capped the queen cells as if they were drones, 9-10 days after the egg laying. Out of 60 accepted false queen cells, 21 (35%) were capped. The shape of false queen cells with drone larvae is unusually long with a characteristically elongate tip which is probably due to the falling of larvae. Bees start the destruction of the cells when the larvae were 3 days old and maximised it before and after capping. Protecting false queen cells in the colony by wrapping, reversing them upside down, or placing in a horizontal position, did not help. The only adult drones that emerged from the false queen cells were those protected in an incubator and in push-in cages. Adult drones from false queen cells had smaller wings, legs, and proboscis than regular drones. The results of this study verify previous reports that the bees do not recognise the different sex of the larvae at least at the early stage of larval development. The late destruction of false queen cells, the similarity in quality and quantity of the produced royal jelly, and the bigger drone cells, allow for the use of drone larvae in cups for the production of royal jelly.

A suggestion for royal jelly specifications / Prijedlog globalnih standarda za matičnu mliječ

This article proposes guidelines for quality standards of royal jelly. The proposals are based on two sets of data; the first from our study of the factors that may affect the royal jelly’s chemical composition (protein and sugar supplementation of beehives) and the second on the analysis of a great number of samples from across Greece to establish natural variability of this product. We compared our findings with the adopted national limits, the proposals of the working group of the International Honey Commission (IHC), and the draft proposal of the International Organization of Standardization (ISO). The studied parameters included moisture, total proteins, sugars (fructose, glucose, sucrose, total sugars), and 10-hydroxy- 2-decenoic acid (10-HDA). Our results indicate that the limits for royal jelly in some countries should be amended and the proposals of the IHC and the ISO reviewed in view of recent data on variability. We believe that our proposals could be considered for setting global standards for royal jelly, as they incorporate national legislations, proposals of scientific groups, experimental data, and updated information. U ovome se članku predlažu međunarodne smjernice za kakvoću matične mliječi. U prvom dijelu istraživanja analizirali smo koliko dohrana bjelančevinama i šećerima utječe na kemijski sastav matične mliječi, a u drugom smo analizirali velik broj uzoraka matične mliječi prikupljene iz cijele Grčke kako bismo ustanovili prirodnu varijabilnost ovog proizvoda. Svoje smo rezultate usporedili s usvojenim standardima različitih država, prijedlogom standarda Međunarodne komisije za med (International Honey Commission - IHC) te nacrtom prijedloga Međunarodne organizacije za normizaciju (International Organization of Standardization - ISO). Analizom su obuhvaćeni sljedeći parametri: vlažnost, ukupne bjelančevine, šećeri (fruktoza, glukoza, saharoza) te 10-hidroksi-2-decenska kiselina (10-HDA). Naši rezultati upućuju na to da neke zemlje trebaju izmijeniti i dopuniti svoje standarde, a IHC i ISO trebaju ponovo razmotriti svoje prijedloge u svjetlu najnovijih podataka o prirodnoj varijabilnosti matične mliječi. Smatramo da bi naš prijedlog mogao poslužiti za utvrđivanje međunarodnih standarda za matičnu mliječ s obzirom na to da obuhvaća podatke iz zakona i propisa pojedinih država, prijedloge znanstvenih i stručnih skupina, podatke iz istraživanja te najnovije informacije iz literature.