ETD system

Electronic theses and dissertations repository


Tesi etd-03182017-230526

Thesis type
Tesi di laurea magistrale
Studio sulle interazioni tra Apis mellifera e la comunita degli impollinatori selvatici in ambiente dunale
Corso di studi
relatore Prof. Petroni, Giulio
relatore Dott. Quaranta, Marino
relatore Dott.ssa Boschetti, Matilde
Parole chiave
  • Apis mellifera
  • dune
  • interazioni
  • impollinatori
Data inizio appello
Riassunto analitico
Insect pollination represents the most spread mechanism of cross-pollination among plants. Up to the 80% of all wild plants use it, and so, it is necessary to maintain the structure and richness of wild plants communities. Many cultivated species get benefits too from insect pollination; researches show yields increase when insect pollinators, like Apoidea, are involved and so the economic value of this service is very high, reaching 153 billion euro/year. Among domesticated animals honeybees (Apis mellifera L., order Hymenoptera, super family Apoidea) is undoubtedly one of the most widespread. From researches on wild plant communities emerge that wild pollinators, especially Apoidea, could be negatively influenced by competition with honeybees. Apis mellifera could become the most representative pollinators on flowers during the season, outnumber the other bee species and even replace them blocking their activity. Because of their great numbers and frequency of visits, honeybees could consume the most part of nectar and pollen resources, so they cannot sustain wild pollinator’s communities anymore, bringing to the extinction of some species. Not all the works agree on the existence of competition between Apis mellifera and wild bees at least in Europe. Honeybees have been involved in crop pollination for a long time and their contribution in agriculture is huge; for this reason, they have been considered very useful and benefic. Whether competition with honeybees has or not a negative impact on wild pollinator’s communities is still an unsolved problem. The goal of our research is to asses if exist such interaction in the dune environment inside the region park of Migliarino San Rossore Massaciuccoli where, from the 90s along the coasts of the park, take place the activity of honey production. What is obtained is a characteristic product called “miele di spiaggia”. Our study focuses on two areas where are present fixed hives inside two SCI (Sites of Community Interest). The first one is inside the SCI “Selva Pisana” in the location called Fortino inside San Rossore estate, and the second is inside SCI “Dune litoranee di Torre del Lago” in Torre del Lago. We use two sampling methodologies: one is active, direct observation along transects, and the other one is passive, using pan traps. The traps were plastic bowls painted in with UV-florescent spray paint of four different colors: red, blue, white and yellow; all the bowls were filled with soapy water. Pan traps has been positioned in 6 sites in San Rossore and 3 sites in Torre del Lago, at increasing distance from the hives; for every site has been positioned 8-12 traps divided in 2 locations for site in San Rossore and 3 for site in Torre del Lago. Direct observations took place in 3 sites in both areas. Both transect and traps took place inside the dune environment. The two methodologies give us different information. Pan traps, which are specific to attract pollinators, give us information about specie composition of pollinator’s community in our study areas; observations help us to understand the presence and activity of different species on vegetation. Our work try to asses if exist a “distance effect”, a change in species composition or activity on flowers of wild pollinators at increasing distance from hives. This is an indirect approach to evaluate the competition between honeybees and wild pollinators, because has been shown by some researches A. mellifera could exclude other pollinators from floral patches because of their presence. Both samplings protocols took place once a month for a period of 4 months from April to July 2016 so to cover the flying period of all bee species from the earliest to the last and the flowering period of most plant species of the dunes.