FUNCTIONAL AND ECOLOGICAL STATUS, VULNERABILITY AND ECONOMIC EVALUATION OF INSECT POLLINATORS IN SERBIA

Pollination is important ecosystem services in terrestrial systems, essential for the reproduction of flowering plants, the conservation of biological diversity, as well as food production. The vast majority of flowering plants (87.5%) are pollinated by insects and other animals, and even about 75% of the main types of cultivated plants in the world can benefit from this type of pollination. Of the 115 most commonly cultivated plants for human consumption, as many as 87, it relies more or less on pollinators, and about 35% of the food produced at global level depends on them. Between plant and pollinators there are very complex relations of mutual condition and influence on reproduction, production, and maintenance of populations and communities, and it is of particular interest to determine what are the main trends and effects of manifesting these phenomena on the gradient from natural and semi-natural - relatively conserved ecosystems to agroecosystems and other predominantly artificial formations, exposed to a strong negative impact. Pollinators are now exposed to a number of negative factors of global change, among which the most important are: climate change, changes in land use, intensification of agriculture and the spread of invasive species - especially pathogens. The decline in the number and variety of pollinators could have a cascading effect on the loss of many other biodiversity segments, as well as major implications for food safety in global terms. The economic value of pollinating services provided by animals in agriculture on a global scale was estimated at 153 billion euros (data for 2005). The most numerous pollinators are insects, and among them are by far the most significant bees (Hymenoptera: Apiformes); of over 2,000 species known in the fauna of Europe, for Serbia we can roughly estimate that there are probably around 800-1,000 species. Flies (Diptera) are the second most frequent visitors of flowers, and among many groups, the most significant pollinators are members of the family Syrphidae. Of the nearly 900 species of hoverflies in European fauna, in Serbia was recorded over 400. So far in Serbia, the butterflies (Hesperioidea, Papilionoidea) have been registered up to 200 species, whereas the heterogeneous non-taxonomic group of Heterocera is more numerous but far weaker investigated; The latest estimates are dealing with about 1,200 species of Macrolepidoptera and more than 1,300 species of Microlepidoptera. Among other insects, it is known that many beetles, wasps, ants, thrips and some others also frequented the flowers, but about their pollination effects is knows very little. Honey bees (Apis mellifera) is arguably the best-known species of pollinators, but other reared and wild bees are more important pollinators worldwide in the production of crops, and certainly, have an invaluable role in the pollination of wild plants. Beside bees (social and solitary), some fly species are reared as pollinators. Bees are undoubtedly the most important pollinator group in the temperate zone, while fly pollinators are much more diverse and more abundant in colder regions (Arctic and Alpine). Butterflies are the most widely studied group of insects, but their role and practical application as pollinators are proportionately considerably less evaluated and quantified. In general, functional-ecological research and various valorizations of the pollinator insect status have been more than 15 years among the priorities of international funding programs for fundamental and applied science, while in Serbia these issues are not yet adequately represented.