Pollination effectiveness of different strawberry floral visitors in Ribatejo, Portugal: selection of potential pollinators. Part 2

Abstract

This study was carried out in a strawberry (Fragaria × ananassa Duch.) field located in Ribatejo, Por- tugal, and aims to describe the qualitative component of the visits for three strawberry floral visitors, attaining the best results in a previous work. The main objectives were: (1) to assess the pollination rate (PR) resulting from a single visit of Apis mellifera L., Syrphidae and native bees, and (2) to characterize the foraging behaviour of each of these categories in order to select the potential pollinators of strawberry crops under open field con- ditions in the Ribatejo. All analysed categories were shown to be potentially useful pollinators, since there were no significant differences among them in the pollination rates, after a single visit. The observed distinct foraging behaviour among them did not result in significantly different pollination rates. Growers are recommended to take advantage of the several pollinators, either the honey bee or the native pollinators (Syrphidae and native bees). The importance of diversifying pollination sources, avoiding the dependence on a single specific group is stressed. This study also suggests measures which envisage the conservation, establishment and increase of native pollinators' populations in the typical agro-ecosystem of the Ribatejo region.