The first draft of this post began back in the summer of 2012 when the milkweed fed our bees in a drought. After a time it ceased blooming, formed pods, and still later cast its downy seeds onto the winds before the cold came. Yet the post was unfinished due to lack of attention or inspiration. Perhaps the next year when the milkweed bloomed again. Well, it did and finished and still we had not posted. Even worse, we were scooped by fellow blogger Petals and Wings in a post with much nicer pictures. And now here we are again, two years later, our milkweed having again burst into scented bloom. Time to extract the pollex and finally publish before we are again watching seeds fly away.
Milkweed is best known as the obligatory host of caterpillars of the monarch butterfly. While an adult monarch can sip nectar from a variety of flowers it must lay eggs on milkweed for there to be future generations of monarchs. So as the milkweed largely took over its flowerbed we began in spite of our sign (Click on the picture to enlarge it and you will see a honeybee flying past just above the "H".) to vaguely regard the little patch as butterfly fodder and of no particular interest to other pollinators.
Then came July of 2012 when we were moaning about the lack of rain and fretful that anything flowering would be deficient in nectar until we smelled the milkweed in bloom and saw the bees visiting. Turning to wikipedia we were reminded that every variety of it is in fact a major source of nectar for honeybees, so abundant that one can shake the blossom and see the nectar fall. We did not try the experiment as we could hardly ever find a plant without at least one bee hard at work. The plant is often described as drought-tolerant but we took that to simply mean that it will not die in dry spell rather than that it would continue to produce abundant nectar under those circumstances.
Consulting our favorite reference, Honey Plants of North America by John H. Lovell, we found a large section about milkweed, another of those plants beloved by beekeepers and despised by the general populace. Deep rooted, growing on nearly any soil, and spread by a cloud of windblown seeds it is oft regarded as a noxious weed. But those deep roots, especially in clay soil, bring forth the life-saving summer nectar. Its flow in Michigan is reported to be about thirty days beginning in early July and so rapid that a colony can gather over ten pounds in a single day. The resulting honey is very light in color with a slight tang that becomes milder with age.
The pollen on the other hand is useless for honeybees and even dangerous. Rather than existing as a loose powder to dust their furry bodies and collect in their corbiculae, milkweed pollen occurs in coherent clumps called pollinia. The manner of propagating these is unique to the milkweed and described in lovely photographic detail along with more of the milkweed life cycle at microscopy-uk.org.uk.
Our own capsule summary is that a pollinator’s leg slips into a slit on the elaborate structure of the milkweed flower whereupon it gets clamped by a corpusculum from which dangle two pollinia. Then the pollinator must withdraw its leg so that after a few minutes the dangling pollinia can dry and twist and form a narrow body. Finally the pollinator visits another flower, where that leg again slips into a slit and the pollinaria contact a small area at the base to achieve pollination. Unlike the dusty pollen she collects on her fur and in her saddlebags, the pollinaria are an irritation to the honeybee. Rather than get on with pollination it is likely to spend a lot of time trying to just get the wretched things off its leg. She may return to the hive for help where, if it can be removed, it is simply discarded rather than used to make bee bread. And that assumes that the honeybee can remove her leg from the flower. A larger pollinator would have no trouble but a honeybee may become trapped and perish. Or she might remove her leg from her body instead, which also does not bode well for her.
Most of the bees we saw working our patch seemed to have avoided the hazard but we did come across one making repeated attempts to fly away from the grip of the flower but unable to loose herself. In that case we were able to gently brush her free and she flew off, presumably to return to the hive. We have read other reports where a samaritan expedited a bee’s release only to have her fly back to the same flower and get trapped again, the lure of the uncollected nectar being too strong.
We also once saw a hovering honeybee engaged in beating a milkweed flower with her foremost legs like a boxer working the speed bag. She seemed to have all her legs with none encumbered by pollinaria. Had she had a narrow escape and was letting the flower know that it had best not try such a trap again? We would welcome any other reports or explanations of such behavior.
And so, having finally completed and published our milkweed maunderings, we conclude with a recent, happy observation not related to bees. We have seen a monarch caterpillar munching away in our milkweed patch as well as a monarch butterfly feeding. Only one of each and not likely to count for much against the numbers lost to disappearing habitat and pesticides but enough to gladden our hearts for a bit.