The South American Black Bumblebee (Bombus pauloensis) as a Potential Pollinator of Alfalfa (Medicago sativa)

Abstract

We assessed if the commercially reared South American bumblebee Bombus pauloensis for-ages resources in alfalfa crops by monitoring their colony activity daily. We analyzed the pollencollected by using pollen traps specifically designed for B. pauloensis nests and counted the numberof bumblebees in the crop. Consequentially, colony activity was found to be highest during themornings; 65% of the pollen trap samples analyzed contained alfalfa pollen grains, and 60% of thetotal pollen loads were identified as alfalfa pollen. Although the honey bee was the predominantpollinator observed in the crop, the high percentage of alfalfa pollen found in the pollen traps of B.pauloensis nests suggests that this species forages resources in alfalfa crops and could be considereda potential managed pollinator.