Eristalini Hoverflies Are Efficient Pollinators for Seed Production of Wild Rocket, <i>Diplotaxis tenuifolia</i> (L.) <scp>DC</scp> (Brassicaceae)

ABSTRACT The selection of pollinators in seed multiplication and genetic improvement programmes must ensure the highest possible productivity and maximum crop yield. The present study evaluates the pollination effectiveness of three different pollinator strategies, two based on two hoverfly species ( Eristalis tenax and Eristalinus aeneus ) and another one based on a blowfly ( Lucilia sericata ), in two varieties of wild rocket. The comparison was made in terms of floral visits, pollen deposition, fertilisation of flowers, and seed yield obtained with the three pollination strategies compared. The number of visits was directly related to the level of flowering, with the highest rate of floral visits observed in E. tenax and E. aeneus (10.4 visits per plant and 8.9 visits per plant, respectively), and L. sericata exhibiting the lowest rate (3.4 visits per plant). The pollen adhesion on stigma in both varieties of wild rocket was greater in flowers pollinated by E. tenax (+257.0%) and E. aeneus (+153.0%) compared to L. sericata . In terms of seed yield, both hoverfly species were found to be significantly more effective in seed yield per plant in Variety 1 ( E. tenax : 34.96 g; E. aeneus : 29.49 g; L. sericata : 14.06 g), as well as in seeds per insect ( E. tenax : 7496.2 seeds; E. aeneus : 4379.9 seeds; L. sericata : 648.0 seeds). Nevertheless, in Variety 2, no significant variations were detected in seed per plant. Instead, pronounced differences were observed in the number of seeds obtained per insect, which was higher in E. tenax (+439.0%) and E. aeneus (+331.7%) compared to L. sericata . The study also demonstrated that the seed germinability of Variety 1 was higher than that of Variety 2, but the impact of the pollinator species was not significant. These findings suggest that E. tenax and E. aeneus are more effective pollinators for wild rocket, compared to L. sericata .