Early this summer, I stumbled on some honeybees that were visiting the mud turned up by a tractor tire in one of my orchards. It struck me as odd because honeybees don’t build their cells out of mud like some bees, they build them out of wax. And they couldn’t have been short on water, because it rained in (over)abundance throughout the spring and summer here.
Luckily, the question came up on my pollinator listserve not long after my observation about the importance of minerals in the diet of bees. (I believe someone observed some bees visiting rusty metal.)
“I am travelling so do not have my reference books but I believe it is well known many bees and butterflies do collect minerals for their diet. The below link reports on bees and butterflies drinking from crocodile tears for their salts for example!
Occasionally I will go down to my stream, and whenever I see one of my honeybees sipping water it is from a wet rock or the mud, not from a clear patch of
water. My beekeeping teacher taught us to give mineralized salts occasionally in the hive to help the mineral needs.
The rusting galvanized metal certainly has iron in it, and who knows what
else. I imagine the bumble bees are after the mineral. couple items regarding iron in honeybees, in the one case speaking of iron in development (I think butterflies need it to reproduce) and iron containing an iron oxide, magnetite, which gives them sensitivity to the magnetic field.
Perhaps the bumble bees are taking in iron.
Hope that is interesting,