Solitary-pollen bees do not produce honey. But they are about 80% (17,000 species) of the worlds bees. Because of the sheer numbers these solitary-pollen bees are the ones that do most of the pollination.
Honeybees are a studied extensively for their behavior. The are an excellent "canary in a coal mine" indicator of environmental pollutants. The appetite of honeybees is a good indicator of bad effects (sub lethal) of environmental pollutants.
Now it seems like use of RoundUp (Glyphosate) can cause collapse of honey bee colonies. One research found that typical amounts of Glyphosate added to agricultural fields could reduce short term memory and learning ability and nectar appetite of honey bees. So the glyphosate reduces colony efficiency resulting ultimately in colony collapse.
Of course EPA/Monsanto says RoundUp is harmless for bees and have research studies to prove it. However, when reading the paper, one realizes that it focuses on mortality. That is the study focused on the effect of RoundUp (Glyphosate) acting as a poison and killing bees. There was no study on the long term effects of RoundUp (Glyphosate) on bees.
An Aside on Sri Lanka
Of the four honeybee species of Sri Lanka, only one-the mee massa (Apis cerana)-is suitable for domestication, because it builds its hive in enclosed spaces, which makes it suitable for beekeeping. -
The bambara and the danduwel massa (Apis florea), small, red bees, build their hives in open spaces such as on trees or high up on buildings. The fourth species, the kano mee, a small stingless honeybee species, produces small quantities of honey.