Efficient and Functional Bee Pollinators of Alfalfa ( <i>Medicago sativa</i> L.) in the Algerian Agricultural Ecosystem

Abstract

ABSTRACT Floral foragers' pollination performance varies by taxon, and many crops rely on insect pollinators to produce fruit. Although honey bees are the primary pollinators for most crops, wild pollinators can sometimes be more effective and efficient. This study evaluated the pollination efficiency of several bee species: Apis mellifera , Megachile spp., and Bombus terrestris (queens and workers) on alfalfa. The research was conducted in the Wilaya of Mila, at Djebel Aougeb, Commune of Oued El Athmania (36°31′48.6″N, 6°39′49.1″ E), during the flowering seasons of 2021 and 2022. The experiments compared the pollination efficiency of the four groups based on pollen deposition per visit, foraging behaviour, and foraging speed. In terms of pollination efficiency, B. terrestris queens deposited the most pollen, visited more flowers per minute, and spent the least time per visit. This was followed by Megachile spp., while A. mellifera deposited the least pollen, visited fewer flowers per minute, and spent more time per flower. Whereas B. terrestris workers primarily collected nectar, contributing less to effective pollination. A significant increase in alfalfa grain yield was observed when comparing insect‐pollinated and unpollinated plants. The findings highlight the economic value of wild bees, particularly Bombus terrestris queens and Megachile species ( M. leachella and M. pilidens ), in agroecosystems. Insect pollination resulted in a substantial increase in fruit and seed production, with pollinated flowers producing up to 17 times more seeds in 2021 and 14 times more in 2022 compared to unpollinated flowers. Open pollination had a significantly greater impact than self‐pollination. To optimise pollination in Algerian alfalfa fields, synchronising the flowering period with the emergence of B. terrestris queens to avoid the dominance of workers and providing nesting habitats for Megachile species, in addition to using Apis mellifera , is recommended.