Love and death at the milkweed saloon

monarch pair
Monarch butterflies on common milkweed

The milk of milkweed is a strong drug. Members of the genus Asclepias — named for the Greek god of medicine — contain “powerful heart poisons that can be used to treat congestive heart failure and atrial fibrillation,” according to this article. Crab spiders that feed on milkweed aphids spin erratic webs, turn pink, grow fat to match the flowers. Monarchs, whose caterpillars eat nothing but milkweed leaves, are said to be immune to the effects of the drug, but I wonder. Would you call a three-thousand-mile mass migration normal behavior? And they’re not alone: the large milkweed bug (Oncopeltus fasciatus), too, is a long-distance traveler, migrating hundreds of miles south each fall to escape the frosts, and returning in the spring.

swallowtail and honeybee
Tiger swallowtail butterfly and Italian honeybee

But the nectar is the main attraction. The globular clusters of flowers emit a fragrance that most humans find a little cloying, but insects find irresistible. Common milkweed has pollinators innumerable that arrive by day and by night: honeybees and bumblebees, wasps, flies, butterflies, moths, and skippers. Many who come to drink, of course, are freeloaders, but the pink cups overflow — there’s enough for all.

milkweed longhorns mating
Milkweed longhorn beetles mating

A large milkweed patch on a sunny day makes me think of a street of saloons in Hollywood’s version of the Old West. The air is electric with danger and desire. While a pair of monarchs circles in graceful courtship, beetles copulate, and sinister assassins lie in wait for their victims. I found a moth swinging dead from a flower by its proboscis, the victim either of an assassin bug — which tends to dispose of its prey in this fashion, after sucking out the juices — or of the milkweed flower itself, which frequently traps insects in the too-narrow grooves of its sexual parts. The milkweed, let’s remember, has its own agenda: by late fall, to begin to release thousands of seeds into the wind on silk parachutes. So right now, it wants to be pollinated. It wants it bad.
dead moth
dead moth, species unknown (to me, at least)

Once established, a milkweed colony can expand rapidly through rhizomes, growing from just a few plants to half an acre in a few years. Then, too, it can dwindle over the course of a decade, finally disappearing altogether. Currently, our largest patch of common milkweed is at the end of the old field where it extends up to the ridgetop, which therefore — presuming that migrating monarchs ride the wind currents along the ridges to some extent — may be ideally situated to attract the first monarchs north in early summer. This year, I spotted my first monarch on June 17. This particular patch is only a few years old, and seems still to be in the expansion mode, filling in a strip of field between the edge of a maturing deciduous forest and a 30-year-old grove of Norway spruce. A couple of vernal ponds, which can collect water from heavy rains throughout the year, lie a short distance away through the woods, which is also littered with abundant fallen and standing dead trees of several species and in all states of decomposition. In short, the place is a hotspot of local invertebrate biodiversity — an insect Mecca.

netwinged beetle orgy
A net-winged beetle orgy

I’ve barely begun to explore the teeming life of the milkweed patch, assembling the better photos into a photo set on flickr. As time and light conditions permit, I hope to augment it. In the meantime, here’s a small selection. As usual, my focus is more on aesthetics than science, but I urge anyone with an interest in natural history to read the article I quoted from above, In a Milkweed Patch, by Marcia Bonta (Hi, Mom!). She — unlike me — has done her research.

I have also scrutinized list after list by scientists that are fascinated by all the insects that live, eat, nectar and/or die on common milkweed and each differs in species’ numbers and kinds. So even though scientists have been studying the common milkweed and its visitors for as long as 113 years–beginning with Illinois naturalist Charles Robertson’s pioneering, 25-year study–there is still much more to be learned about these intriguing wildflowers and their inhabitants.

yellow skipper 2
tawny-edged skipper (I think)

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Dave Bonta (bio) crowd-sources his problems by following his gut, which he shares with 100 trillion of his closest microbial friends — a close-knit, symbiotic community comprising several thousand species of bacteria, fungi, and protozoa. In a similarly collaborative fashion, all of Dave's writing is available for reuse and creative remix under a Creative Commons Attribution-ShareAlike 3.0 United States License. For attribution in printed material, his name (Dave Bonta) will suffice, but for web use, please link back to the original. Contact him for permission to waive the "share alike" provision (e.g. for use in a conventionally copyrighted work).

14 Comments


  1. the down was used
    by some Middlewestern pioneering types
    as pillow and quilt filler

    I have naturally
    spun some

    short fiber as it is
    it must be spun with fleece

    I collected a bag of it
    set the bag next to my wheel
    and as I’d reach in for a handful
    some would float right up
    out of the bag
    and into the room

    one of my favorite
    plants

    Reply

  2. fyi – Asclepius is the demigod, Asclepias is the milkweed genus. very interesting, thanks

    Reply

  3. anon – Omigosh, you’re right! I’ll make the change.

    suzanne – I didn’t know one could spin it – great comment! Adds a whole new dimension to the post. Thank you.

    Reply

  4. I’m not sure anyone else has, Dave
    or for any reason other than
    the one that impelled me:

    I see fluff
    I just have to give it a twist . . .

    Reply

  5. I see fluff
    I just have to give it a twist . . .

    Heh. I’ll bet the editor of the National Enquirer says that too!

    Reply

  6. Lovely, Dave, all those beuatiful flowers and insects! I don’t think I’ve ever seen a milkweed plant, maybe they don’t grow around here. I do have a gorgeous pod that someone gave me that I think is milkweed – it came from the hotter drier interior of BC. It looks rather erotic.

    Reply

  7. Fascinating information, Dave. You are so interestingly encyclopedic. Being your particular mother’s son helps, I guess, giving you a headstart over most people. Though I’m shockingly lacking in natural history knowledge, I love such personal journeys into the heart of the miniature world beneath our feet. A favourite book of mine is Fabre’s “The Secret Life of Insects”. Do you know it?

    Reply

  8. Great post! Églantine and I spend a lot of time checking out our Milkweed patches for insect photo ops. We are often rewarded. I like your idea of a Flickr set re milkweed. Perhaps I should gather my photos in a new set.

    Reply

  9. marja-leena – I haven’t checked on the web, but with close to dozen native species of milkweed in North America, I’m sure you must have some out in British Columbia. And yes, they too tend to make very cool pods! We have two different Christmas tree ornaments fashioned from the pods of common milkweed.

    Natalie – Fabre is one of my favorite natural histroy authors of all-time, even if my ignorance of French forces me to read him in translation. See here.
    I’m glad to hear you enjoy these kinds of posts. When I started blogging, I didn’t intend to write about nature at all — that’s my mom’s beat — but I couldn’t keep it out! And I very much appreciate hearing that these sorts of posts are reaching a wide variety of readers, not just my fellow nature-nerds.

    Ontario Wanderer – Thanks! I’ve just started using Flickr – it’s more time-consuming to retrieve code from than Photobucket, which I had been using, but I like the ability to group pictures into sets and share photos more easily. I’ll check out your own flickr page as soon as I get the chance.

    Reply

  10. this entry has inspired me, Dave
    I loked through my milweed photos
    (some blooms but mainly those wonderfully
    erotic pods)

    and I just happen to have
    {still] that bag of down and I’m spinning
    a little skein with deep purple fleece
    so the down shows
    and I’ll send you a photo
    when I have some done

    I’m also finding that spinning is great
    rehabilitative activity
    for my reattached torn ligament thumb

    always great to accomplish
    more than one thing
    in doing something for which
    one has a passion

    Reply

  11. That sounds great, suzanne. I’ll look forward to that photo.

    The mere thought of a torn thumb ligament gives me the heebie-jeebies. Glad to hear you’re recovering. And it’s gratifying to think that my post might have helped in some small way.

    Reply



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