Search Results

You are looking at 1 - 4 of 4 items for

  • Author: Andreas Thrasyvoulou x
Clear All Modify Search
Open access

Maria Dimou, Chrysoula Tananaki, Vasilios Liolios and Andreas Thrasyvoulou

Abstract

Pollen is very important for honey bee colony development and nutrition. It is also a valuable product for human consumption, considered to have high nutritional value. In this study, we performed melissopalynological analysis of 285 pollen load samples collected from 44 apiaries throughout Greece. The analysis revealed 229 plant taxa represented in total. The abundance of each pollen type varied among the geographical areas from which the samples were collected. We also observed variation among samples collected from the same geographical region. The most frequently found families were Fabaceae, Asteraceae and Rosaceae. The most frequently observed taxa were Brassicaceae, Carduus type, Cistus and Papaver rhoeas. Statistical analysis showed that the geographical classification of pollen samples among northern, central and southern Greece is possible.

Open access

Georgios Goras, Chrysoula Tananaki, Maria Dimou, Thomas Tscheulin, Theodora Petanidou and Andreas Thrasyvoulou

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.

Open access

Georgios Goras, Chrysoula Tananaki, Sofia Gounari, Elissavet Lazaridou, Dimitrios Kanelis, Vasileios Liolios, Emmanouel Karazafiris and Andreas Thrasyvoulou

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.

Open access

Dimitrios Kanelis, Chrysoula Tananaki, Vasilis Liolios, Maria Dimou, Georgios Goras, Maria Anna Rodopoulou, Emmanuel Karazafiris and Andreas Thrasyvoulou

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.