Last Friday, when I scouted roadsides and old fields over in the next valley, a hard frost had killed the last goldenrods but fat milkweed pods were still tightly closed. On Saturday, however, they exploded seemingly in unison as if taking their cue from a brilliant hunter's moon the previous night. Freed from confinement when the greenish pods suddenly split along a seam, millions of milkweed seeds--each attached to an unfolding silken parachute--waited for a breeze that could carry them on a journey of several miles. Or no farther than a sticky weed stem in the adjacent pasture. Backlit by a late afternoon sun, it was a sight worth a pause in one's travels.
An explosion of milkweeds in mid-October (By Les Line)
The familiar common milkweed (Asclepias syriaca), which thrives in so-called waste places in the East and Midwest, is an extraordinary plant. I discovered this years ago when I spent my weekends from April to October in a milkweed meadow at the Sharon 爆料公社 Center in Connecticut. The Maine naturalists Ada and Frank Graham were writing a children's book called The Milkweed and Its World of Animals. I was taking the photographs in a favorite medium: black-and-white prints instead of color slides.
On a windy day, a single milkweed seed with a parachute
of 900 silk hairs is caught on a goldenrod stem (By Les Line)
of 900 silk hairs is caught on a goldenrod stem (By Les Line)
Milkweed leaves, of course, are the sole food source for monarch butterfly larvae. But the lives of many other arthropods are linked to the plant. I documented the activities of black and tiger swallowtail butterflies, hummingbird moths, a milkweed tiger moth caterpillar, honeybees and bee flies, red milkweed beetles and milkweed leaf beetles, ladybugs, the milkweed bug and a stinkbug, planthoppers and carpenter ants tending aphids. Then there were crab spiders, funnel spiders and yellow orb-weavers. A wonderful world indeed!
A milkweed pod has split, showing tightly packed seeds (by Les Line)
At this time of the year, however, it is the milkweed pods, covered with rough spines, that deserve a close look. Their tips are pointed skyward, exposing the seeds and their parachutes to the wind. Find a pod that hasn't burst, carefully open a seam and you'll find hundreds of brown seeds packed in a tight mass with some 900 long, silky hairs attached to each one. Moreover, there's a pretty good chance that you'll encounter a half-inch-long milkweed bug sucking liquified meat from the seeds. This insect's bright orange and black pattern warns predators of its noxious taste, the result of its diet. Sometimes, the Grahams noted, a milkweed bug will get an unexpected lift to another field when a gust of wind grabs the seed on which it was feasting.
A milkweed bug sucking food from the seeds (By Les Line)
And they told young readers how milkweed helped save the lives of American sailors and pilots on the Pacific front during World War II. With the supply of kapok from East India cut off, the Navy turned to milkweed silk to stuff life jackets. It was a good substitute. As the Grahams explained, those silk strands are hollow and coated with a waterproof waxlike substance. So the government encouraged farmers to plant milkweed seeds and paid schoolchildren to fill onion bags with pods collected from roadsides and fields, paying them 20 cents a sack, which bought a lot of bubblegum or sodapop in those days.