L'oeuvre d'Anna Maurizio

Abstract - The scientific achievements of Anna Maurizio
On the occasion of Anna Maurizio's retirement, O Morgenthaler (1966) gave a description of her professional career. After entering the Federal Station of Dairy and Bacteriology in Liebefeld-Bern in 1928, A Maurizio published her first papers on mycology of honeybees (1934-1935). Trained in botany, entomology and microscopic studies, she was plainly destined to take charge of honey pollen analysis and rapidly understood the advantages to be gained by a knowledge of pollen. She initiated the Bienenbotanik concept and wrote : "The concept of Bienenbotanik (bee botany) comprises the relations of the honeybees with their plant environment. To this field belong first of all bee plants (secretion of nectar, collection of nectar, production and collection of pollen), poisoning of honeybees by plants, microscopy of honey and pollen and also the relation of apiculture and agriculture. Connected with Bienenbotanik in a larger sense is also research about honeydew, use of pollen by the bee colony, physiology of the nutrition and poisoning by phytosanitary products" (Maurizio, 1960c). If pollination is disregarded, a field she hardly broached, at least one original contribution can be found for each of the great themes in the total of her publications. The pollen analysis of honeys was the initial theme. This field of research began with a publication by Pfister (1895), which was used by laboratories to verify the geographical origin of honeys; however, it remained entirely empirical. In 1935, Zander published a manual with a modern approach; the research of A Maurizio continued the work of Zander by completing it and giving it a new dimension with the introduction of the notion of typology. Typology of honeys. The theme of the typology of honeys has resulted in a long series of publications from 1936 until the present day. Honeys from a determined geographic or ecologic zone are described with the aim of determining the palynological essentials. The pollen spectrum of a certain honey forms the link between honeybee activity and the surroundings. This research led the author to start questioning all existing methodology of pollen analysis. Methodology. The first very important contribution (Maurizio, 1939) was a new approach to quantitative pollen analysis. The new method opened the door to the investigation of monofloral honeys which was to be continued for more than 20 years. The body of publications on this theme contribute considerably to the knowledge of melliferous flora, especially that in Europe. On the basis of this know-ledge, Méthodes de la Melissopalynologie (Louveaux et al, 1950) was edited within the framework of the activities of the International Commission of Bee Botany. Maurizio was the founder and the first president of this commission (Maurizio 1975b). Mellissopalynological observations. These consist of 19 short communications which were published between 1938 and 1963 (see annex). They deserve to be regrouped for their precise and efficacious approach to a mellissopalynological enigma. Poisoning of honeybees by plants. The bibliography on this subject is already extensive (Maurizio, 1945b). The personal research of A Maurizio concerns Ranunculus (crowsfoot), lime, and horse chestnut. Methods for maintaining worker bees in cages in the laboratory were developed during identification studies on toxic substances contained in the pollen. This research was the starting point for studies on the physiology of honeybee nutrition which began with the research on mellissopalynology. A number of publications followed, mainly as a result of the discovery of the connection between longevity of worker bees and nutrition (Maurizio, 1950-1954a). Collection of pollen. A Maurizio was able to study the returns with the aid of the "pollen trap". She was particularly interested in "mixed" pollen loads containing pollen grains from 2 or more different plant species. The percentage of these pollen loads varies and seems to be higher when the colony is in a difficult situation. Pesticides and poisonous gases. The diagnosis of honeybee poisoning by pesticides and gases emitted by the chemical industry became a major challenge for the Liebefeld laboratory : methods for calculating lethal doses were elaborated, and the problem of fluor emissions by aluminium factories was specifically studied. Chromatography. At the beginning of the 1950s paper chromatography of sugars was used in the laboratories which analyzed honey. A Maurizio introduced this method to complement pollen analysis. As a result of the new technique, considerable progress was made in the analysis of monofloral honeys. Due to the possibility of analyzing very small quantities, parallel studies of nectar became feasible. From the nectar to the bee and finally to the honey, sugar chromatography showed all the transformations of the original material; and honeydew was not forgotten. Nectar secretion. A Maurizio was very interested in polyploid plants : fodder plants or ornamental flowers visited by honeybees. Polyploidy causes changes in quantity and quality of the secreted nectar, but not in all cases with obvious advantage for honeybees. A Maurizio and plant physiology specialists were able to study the functioning of the nectaries, site of important enzymatic activities. In conclusion, it can be said that the scientific work of Anna Maurizio is a mine of information - both facts and methodology - which will provide knowledge for many years to come. Her contribution to changing pollen analysis of honeys from the empiricism of the beginning of the century to a modern scientific discipline, mellissopalynology, has also been a great value to apiology.