Studying fungal diversity in various environmental samples provides us with valuable knowledge about the occurrence of fungi of medical and ecological importance. Moreover, fungal composition may also characterise well the botanical and geographical source of food products, such as the origin of the spore enriched honeydew honeys. Thereby, we identified a wide spectrum of fungi found in 100 of honey samples from various geographical sources - most of them were from Italy, Greece and Hungary. Our honeydew honeys had a higher mean of the number of spore types found in them than floral honeys had. Statistically significant differences in diversity were found regarding the botanical source (p = 1.29 x [10.sup.-9]) and the climatic classification (p = 2.28 x [10.sup.-2]) according to Kruskal-Wallis rank sum tests. Most frequently encountered genera included ubiquitous saprotrophic species (Alternaria, Cladosporium, Epicoccum nigrum, Stemphylium), both in floral and honeydew honeys. On the other hand, certain sooty moulds like Aureobasidium pullulans, Tripospermum and Capnobotrys were rather present in different types of honeydew honeys. Metschnikowia reukaufii, the nectar inhabiting yeast reached considerably high quantities in floral honey samples. Present findings encourage further studies on quantifying the occurrence and the indicator value of specific fungal elements in honey, concerning its origin.

Key words: botanical origin, diversity, fungi, honey, honeydew

INTRODUCTION

The diversity of fungal species is an intensively studied subject because of ecological, phytopathological and pharmaceutical importance of fungi. Morphological identification of species is often used to detect various groups of fungi, e.g. allergenic and phytopathogenic fungi in air samples, Ingoldian fungi in stream water, fossilised spores in historical or forensic samples. Honeys, especially those of honeydew origin are also rich in fungal spores (Dimou et al. 2006, Magyar et al. 2005, Perez-Atanes et al. 2001, Seijo et al. 2011, Zander 1935). Spore content of honeys arose increasing interest, because it can help to determine their source. Knowing that fungi frequently live in a strong association with plants, different fungal species assemblages might be as typical of the honey as the spectrum of pollen grains.

Honeydew elements, namely fungal spores, hyphae fragments and algae are used as indicators of honeydew origin of honeys (Louveaux et al. 1978), due to their frequent accumulation in honeydew. Honeydew is the sugary secretion of phytophagous insects (i.e. Rinchota: Homoptera, Magyar et al. 2005). It is collected by bees mainly from late summer till September when there is a limited source of nectariferous flowers (Persano-Oddo et al. 2000). Honeydew honeys often reach a higher price than other types of honey--speaking mainly of Austria, Switzerland and Germany (Bogdanov and Martin 2002). In comparison with floral honeys, honeydew honeys have a higher mineral (Gonzalez-Miret et al. 2005) and oligosaccharide content (Foldhazi 1994). Certain countries' total honey production, for example that of Greece, comes predominantly from honeydew honey (Thrasyvoulou and Manikis 1995). Thereby, the reliable identification of such honeys is of special commercial interest.

During traditional melissopalynological analysis, honeydew elements are quantified next to pollens. A careful differentiation between the pollen types of nectariferous and those...