Foraging bees of the onion (Allium cepa L.) and their impact on seed production in Tizi-Ouzou area (Algeria)

Foraging insects of Allium cepa L. (Liliaceae) have been studied during two flowering periods in 2016 and 2017, in the region of Tizi Ouzou (northeastern Algeria). At first, our observations showed that the majority of forager insects, which led and gave preference for their foraging activity of this plant, is Hymenoptera Apoidea. However, we noted also that the Apidae, Apis mellifera and the Halictidae, Lasioglossum malachurum, and L. pauxillum are the most frequent visitors on onion flowers. We highlighted all these species perform positive foraging regardless of the product harvested. Moreover, as for food research, our study described a specific behavior of honey bee, which devotes its visits to the exclusive harvesting of nectar whereas the visits of two other species are much more devoted to the mixed collection. According to other studies about Allium cepa L. (Liliaceae), we confirm the presence of pollinating insects greatly contributes to the improvement of production; indeed the grain yield obtained by cross-pollination is higher than obtained by autogamy. We gathered data showing the average weight of seeds obtained per free quadrates is 4.14 g and that of caged quadrates is 0.09 g.