Andreas Thrasyvoulou

New multiresidue method using solid-phase extraction and gas chromatography–micro-electron-capture detection for pesticide residues analysis in royal jelly

Royal jelly, one of the most important bee products, can be contaminated with pesticide and/or antibiotic residues resulting from treatments applied either inside beehives or in the agricultural environment. A new multiresidue method was developed and validated for analysis of nine pesticides in royal jelly. Solid-phase extraction RP-C(18) cartridges were used for sample purification and isolation of analytes. Final solution was analyzed with GC and micro-electron-capture detection. Four synthetic acaricides used by beekeepers (bromopropylate, coumaphos, malathion and tau-fluvalinate), and moreover one pyrethroid, two organochlorine, and two organophosphate insecticides were tested. Linearity is demonstrated for the range of 0.0025-1mgkg(-1), with correlation coefficients ranging from 0.99991 to 0.99846, depending on the analyte. Overall recovery rates from royal jelly blank samples spiked at five fortification levels ranged from 80.8% (lindane) to 91.3% (ethion), well above the range defined by the SANCO/10232/2006 and EC/675/2002 documents. The limit of quantification was <0.003-0.005 mg kg(-1) depending on the analyte, and the reporting level of the method, defined as the lowest recovery level, was 0.005 mg kg(-1).

Seasonal variation in vegetation and pollen collected by honeybees in Thessaloniki, Greece

Pollen is important for the nutrition of honeybees and it is necessary for their survival and reproduction. In this study, we collected daily the pollen pellets from four colonies and also recorded the plants in flower in the area around the apiary, over a two‐year period. Field records revealed the presence of 204 species with Asteraceae, Fabaceae and Rosaceae being the most specious families. Although honey bees collected more than 140 pollen types, the main pollen sources (>60% of the total weight) came from less than ten taxa. The most important pollen types with respect to total weight were Sisymbrium irio, Papaver rhoeas, Verbascum sp., Polygonum aviculare, Zea mays and Olea europaea. The use of pollen traps proved a more accurate method to record the type and the foraging period during which the honeybees collect pollen, compared to field observations.

Efficient use of pollen traps to determine the pollen flora used by honey bees

Summary We investigated the trade-off between accuracy of results and practical applicability of using pollen trap samples to record the pollen flora of an area. We calculated the minimum representative amount of trapped pollen that needs to be measured. We systematically examined the bee flora of an area for a 2–year period to determine the necessary frequency of sampling. We concluded that even 5 to 10% of the total trapped pollen can give sufficient information about the pollen sources of an area. Moreover, samples of 3–day trapping duration collected at 6–to 9–day intervals through one year were sufficient to catalog the pollen flora of the area.

Investigating plant—pollinator relationships in the Aegean: the approaches of the project POL-AEGIS (The pollinators of the Aegean archipelago: diversity and threats)

Summary Worldwide, there is a well-documented crisis for bees and other pollinators which represent a fundamental biotic capital for wild life conservation, ecosystem function, and crop production. Among all pollinators of the world, bees (Hymenoptera: Apoidea) constitute the major group in species number and importance, followed by hover flies (Diptera: Syrphidae). The Aegean constitutes one of the worlds hotspots for wild bee and other pollinator diversity including flies (mainly hover flies and bee flies), beetles, and butterflies. Despite this advantage, our present knowledge on Greek pollinators is poor, due to a lack of focused and systematic research, absence of relevant taxonomic keys, and a general lack of taxonomic experts in the country. As a result, assessments of pollinator loss cannot be carried out and the causes for the potential pollinator loss in the country remain unknown. Consequently, the desperately needed National Red Data list for pollinators cannot be compiled. This new research (2012–2015) aims to contribute to the knowledge of the pollinator diversity in Greece, the threats pollinators face, as well as the impacts these threats may have on pollination services. The research is conducted in the Aegean archipelago on > 20 islands and several mainland sites in Greece and Turkey. Prime goals are: i. the assessment of bee and hover fly diversity (species, genetic); ii. their pollination services; and iii. the effects of climate change, grazing, intensive bee-keeping, fires, electromagnetic radiation on bee diversity and ecology, as well as on plant-pollinator networks. At the same time, this research contributes to the taxonomic capital in Greece and the Eastern Mediterranean, focusing on the creation of the first identification keys for pollinators, the training of new scientists, as well as the enrichment and further development of the Melissotheque of the Aegean, a permanent reference collection of insect pollinators established at the University of the Aegean.

Discriminating pine and fir honeydew honeys by microscopic characteristics

Summary We performed a microscopic analysis of 73 samples of fir (Abies cephalonica) and pine (Pinus sp.) honey from four regions of Greece during 2004. The analysis resulted in the identification of spores of six fungal genera (Alternaria, Cladosporium, Coleosporium, Fumago, Heterosporium and Stemphylium) and urediospores of rust fungi. Fir honeys had a smaller ratio of honeydew elements to pollen grains and lower abundance of honeydew elements than pine honeys, while spores of the genus Coleosporium were present only in pine honeys. The results showed that the botanical origin of pine and fir honeydew honeys could be distinguished by microscopic analysis. Discrimination based on the geographical origin of the honeys was not accomplished.

Brood and honey production of honey bee colonies requeened at various frequencies

SUMMARYForty colonies of Apis mellifera macedonica were established in Greece with naturally-mated sister queens, two frames of sealed brood and 2 kg of bees, and requeened either every year (A), e...

Pollen analysis of honeybee rectum as a method to record the bee pollen flora of an area.

Pollen is very important for the bees’ nutrition and it is necessary for their survival and reproduction. In this work we studied the possibility of recording the pollen flora of an area by examining the pollen content of the rectum of honeybees (Apis mellifera L.) and comparing the results to these coming from pollen traps. We concluded that the pollen analysis of the rectum of honeybees could be used as a fast screening method of the bee flora of an area. However, for quantitative results, additional methods such as pollen pellet analysis should be applied.ZusammenfassungDie Kenntnis der Bienenpflanzen in einer Gegend ist von grundlegender Bedeutung für die Entwicklung der Imkerei. Pollen ist für die Ernährung der Bienen, ihr Überleben und ihre Reproduktion von essentieller Wichtigkeit. Als Methode der Erfassung der Pollenpflanzen in einer Gegend werden weithin Pollenfallen verwendet, für einige Bienenarten ist dies allerdings nicht praktikabel oder nicht wünschenswert, da die Pollenfallen das Nektarsammeln der Völker negativ beeinflussen. Hier untersuchten wir die Möglichkeit, die Pollenpflanzen in einer Gegend anhand des Pollengehaltes im Enddarm (Apis mellifera L.) zu erfassen und die Ergebnisse mit denen von Pollenfallen zu vergleichen. Wir untersuchten den Pollengehalt des Enddarms von Ammenbienen und Bienen sowie die aus Pollenfallen gewonnenen Pollenladungen aus zwei Völkern im Frühjahr und im Herbst. Die Ergebnisse der Untersuchung zeigten keine Unterschiede in der Häufigkeit verschiedener Pollen zwischen den Ammenbienen und den Bienen unterschiedlichen Alters. Dagegen zeigte eine statistische Analyse in den meisten Fällen signifikante Unterschiede zwischen den beiden Methoden zur Erfassung des Pollens (Pollenfallen und Enddarmanalyse). Wir schließen daraus, dass die Pollenanalyse des Enddarms von Honigbienen als rasches Sichtungsverfahren der Bienenflora in einer Region verwendet werden könnte. Allerdings sollten für eine quantitative Analyse zusätzliche Methoden wie die Untersuchung von Pollenhöschen Verwendung finden.

High frequency sounds produced by Cyprian honeybees Apis mellifera cypria when confronting their predator, the Oriental hornet Vespa orientalis

Honeybees face several predators and their ability to express collective defence behaviour is one of their major life traits that promote colony survival. We discovered that, while confronting attacks by the Oriental hornet Vespa orientalis, Apis mellifera cypria honeybees engage in a distinct acoustic behaviour: they produce a characteristic hissing sound of unexpectedly high frequency. When recording and analysing these hissing sounds during an extended sample of artificial attacks by hornets, we found that honeybees can produce sounds covering a wide frequency spectrum with a dominant frequency around 6 kHz. Notably, these acoustic emissions are distinct from the background noise of neighbouring flying bees. These results provide a detailed description of the sounds generated by A. m. cypria when defending their nest against hornets, and they could be used for future research to better understand the biological function of the acoustic behaviour in honeybees’ colony defence.ZusammenfassungWährend der Abwehr von Angriffen durch die orientalische Hornisse Vespa orientalis zeigen die zyprischen Honigbienen Apis mellifera cypria ein spezifisches akustisches Verhalten, bei dem sie einen charakteristischen Zischlaut von unerwartet hoher Frequenz erzeugen. Dieser charakteristische Ton wird während der Annäherung des Räubers und während der Auseinandersetzung mit verteidigenden Bienen am Eingang der Kolonie hervorgebracht. Wir nahmen diese Zischlaute während einer ausgedehnten Serie künstlicher Angriffe von Hornissen auf und analysierten sie. Für die Aufnahmen verwendeten wir ein mit einem Marantz PMD 670 Digitalrekorder verbundenes Sennheiser ME64 Mikrofon. Die Aufnahmen wurden unter Verwendung der Avisoft und Seewave Software untersucht. Wir ermittelten, dass die Bienen ein weites Frequenzspektrum mit einer dominanten Frequenz um 6 kHz erzeugen können. Die Zischlaute zeigten ein bis zu 16–17 kHz ausgedehntes Spektrum, das bis zu 30–35 harmonische Bänder einschloss. Die Untersuchung von 93 an 9 Kolonien aufgenommenen verschiedenen Zischlauten ergab keine Hinweise auf akustische Kennzeichen der unterschiedlichen Kolonien. Insbesondere waren die akustischen Emissionen deutlich von den durch benachbarte fliegende Bienen hervorgebrachten Hintergrundgeräuschen abgesetzt. Diese Ergebnisse beinhalten eine detaillierte Beschreibung der von A. m. cypria bei der Verteidigung gegen Hornissen hervorgebrachten Töne und können in zukünftigen Untersuchungen zu einem besseren Verständnis der biologischen Bedeutung des akustischen Verhaltens bei der Nestverteidigung der Honigbienen beitragen.

Effect of bumble bee pollination on greenhouse strawberry production

Summary In this study, bumble bees (Bombus terrestris) were used as pollinators in the hydroponic cultivation of strawberries in a greenhouse during winter. We supplied IN Hoagland nutrient solution three times per day to 160 strawberry plants (var. Selva) growing in two 10 cm diameter pipes filled with perlite. One row (control) of the strawberry plants was covered with a fine mesh in order to prevent bee visitation whilst other was open to pollinators. The fruit was collected and weighed weekly during the harvest period. Deformed fruit was counted separately. The results showed that the row pollinated by the bumble bees produced more well-shaped fruit and the total marketable fruit production was double compared to the control row.

A comparison of three methods for assessing the relative abundance of pollen resources collected by honey bee colonies

Summary We compared three different methods for determining the presence and abundance of various pollen resources collected by honey bees: 1) a colour-based segregation of the pollen loads collected in pollen traps; 2) examination of trapped pollen in distilled water; and 3) examination of beebread in distilled water. We concluded that all three methods can give satisfactory qualitative information about the main pollen sources. However, we found significant differences among the three approaches regarding the abundance of pollen resources.