Effect of honey bees (Apis mellifera) and wild insect pollination on rapeseed (Brassica napus) yield in the Argentine Pampas: Results of a caging experiment

A honeybee on rapeseed

by Scally et al.

Rapeseed (canola) can produce higher yields when its flowers are visited by insects. In the Argentine Pampas, farming is highly intensive and there are few natural areas that support wild pollinators. This makes it especially important to understand how both managed honeybees and wild insects contribute to crop production.

We studied how insect pollination affects rapeseed by comparing three groups of plants: those open to all insects, those visited only by honeybees (Apis mellifera), and those from which all insects were excluded. Plants visited only by honeybees produced 33% more seeds than plants without insect visits. Plants exposed to all insects produced 20% more seeds than plants without insects.

Higher yields were mainly due to plants producing more fruits and more seeds per fruit. Seed quality was also better in pollinated plants, with higher ripeness, germination, and vigor.

Our results show that insect pollination is important for rapeseed production even in highly intensive farming systems. Supporting wild pollinators through appropriate agricultural practices, and using managed honeybees when needed, could help increase crop yields in the Argentine Pampas and other similarly intensified agricultural regions.

 Read the scientific publication in JPE.