Common Milkweed, Asclepias syriaca, is a plant of the open fields. Many people tell me that milkweeds growing in the field are a sign of mismanagement. It seems to confuse them when I suggest that the presence of milkweeds only signifies poor management if you are managing for a condition that doesn’t include milkweeds. Milkweeds in a pasture or hay field indicate poor management, but milkweeds in a field being managed for diverse native grassland species do not, so don’t use that as an argument that I’m not caring for my fields. This is the point at which I turn the conversation towards the weather, which my daughter says is the only subject I’m capable of handling in social situations.
The fully opened milkweed blossom is a nectar factory that feeds a multitude of different species. I’m especially interested in pollinators and spend a lot of time watching the native bees. A few weeks ago I was with some backyard fruit growers who were lamenting the decline of the European Honeybee and wondering how their flowers would be pollinated if things didn’t improve. When I suggested they try managing for native bees that could provide the same pollination service, they looked at me as if my hair had caught fire. Apparently, any acceptable substitute had to share the honeybee’s ability to work on demand as well as produce a marketable byproduct.
This grasshopper is eating a portion of the flower. Milkweeds contain steroid glycosides and other toxic substances that make the plant unpalatable to all but a few species that have evolved to deal with the toxins. The concentrations of toxins vary throughout the plant, so the grasshopper may be feeding in a less dangerous area. The tiny white spot on the grasshopper’s back is the empty skin of a tachinid fly egg. The larva has recently hatched and made its way inside the grasshopper, where it will feed until ready to pupate. The grasshopper will not survive the activities of this parasite. Perhaps milkweed toxin is a remedy to tachinid fly infestation.
The flowers are even attractive pre-bloom. Like many plants with multiple blooms, the flowers develop and open in succession, so the blooming and pollination activities occur over a long period.