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The Life of the Milkweed - TO SUMON (36)
NinaM
![Gold Star Critiquer/Gold Note Writer [C: 608 W: 0 N: 1516]](http://i1.treknature.com/misc/g-n-g.gif) (4981) | I am back after my first week of work! The thing is, I walk every day with Toupti, my little dog, and along the path there are fields filled with wildflowers... at that time of the year, it is a joy to walk by the milkweed. I have always loved milkweed and I have always been fascinated by the multiple transformation it goes through in a single season of a few months. All plants transform themselves continually, from the seed to the seedling, then the small plant into the mature plant leaving its seeds. The plants we see, walking along a road or a trail, at the beginning of summer and the ones we see at the end seem totally different but they are the same, gone through tremendous changes, fruit of evolution to allow the perennity of plants. Plants do move a lot but our eyes just cannot detect their continuous movement to reach the sun, the water underground, or whatever it is that they need, elongating, ramping and crawling wherever to meet their needs.
The field where we walk is along a slump, kind of a small stream coming down from the mountains around the area, then into the lake. The birds there differ completely from the birds in our backyard. You may find Red-Shouldered Blackbird, and the female is brown, with her long tail, so beautiful. There are warblers and you can also hear the American Goldfinch getting ready to sleep, as I usually go there at the end of the day.
On this picture you see the Milkweed flowers. In French, we call it Asclépiade commune, for Common Milkweed (asclepias syriaca, L.) They grow in bunches in this field and these days, one can smell their sweetness in the warm wind. Truly exhilarating. They buzz with many bugs and I have seen one with so many ants.
They are mainly host for the Monarch, that beautiful butterfly that travels from here down to Mexico every year and their youngs come back here... to lay eggs again, on the milkweed.
I found very interesting information in a book called "Eastern Forests", a Peterson Field Guide, that you will find at the end of my notes.
The most intriguing part is that milkweed is a very toxic plant and that the Monarch, feeding on it, thus become very toxic. Milkweed contains the same toxic substance as Foxglove and they are the only butterfly family, in the Northern part of America, to have built resistance against the toxicity. I'm amazed to find a higher intelligence in any living creature every time I read about it.
I have posted in the workshop two pictures. The first one is showing you the whole plant. The second one is showing you its seeds at fall. Before the seeds are seen, they are contained in a small cocoon that we used to call, when I was a kid, "des petits cochons" (small pigs). Don't ask me why but we would become very excited to go out and find les petits cochons. They are so beautiful and when you see it in a whole field, it is a fantastic sight.
I also want to add that without TN, I wouldn't have searched the way I do to find information about plants or animals. It is such a fantastic adventure for me to learn about the world through nature. My eye has developed a new ability. I have studied plants about 15 years ago, to become a phytotherapist. But I couldn't tell the name of the plants in a field the way I do now. My eye sees them, find them, and recognize from the books I read or the plants that I see here, on TN. It is a fulfilling experience for me, stronger than just study what a plant can do for you... well, not that it is worthless, oh no! but it is far more enriching to find them on my path... and learn about them.
Imagine, I posted a picture of St.John's Wort that I grow in the garden. The week after, while walking, I find the wild species all along the path where I walk with Toupti!
I hope you enjoy!
Francine
Shot with my TZ4 camera, totally automatic, on "Intelligent Mode" ;-)))
ISO 400
Shot amidst a multitude of black flies and mosquitoes.
MILKWEED ECOLOGY from the "Eastern Forests"
Milkweed are abundant in old fields throughout eastern North America. Flowers develop into conspicuous seedpods and seeds are attached to feathery, parachute-like structures. Milkweed is named for its sap, a milky sticky juice. Eleven milkweed species occur commonly in eastern North America, though the family (which is motly tropical) is represented globally by more than 250 genera and 2000 species.
Insects abound around milkweed flowerheads. You should see Bumble Bees, Honey Bees, ants, wasps, and butterflies of several species, including the brilliant orange and black Monarch and probably the less conspicuous hairstreeks. Close inspection should reveal well-camouflaged crab spiders lurking within the flowerheads. Smaller insects, such as flies and honey bees, may become entrapped in the flowers and be struggling to escape. Predatory insects, such as colourful yellow jackets and hairy black tachinid flies are usually in the vicinity.
A visit to a milkweed clump at dusk can also be rewarding, as you might see hawk or sphinx moths, geometer moths, and underwing moths.
Milkweed leaves are usually relatively undamaged, but large, yellow, white, and black striped Monarch caterpillars may be munching on them. By midsummer, boldly patterned, orange-red milkweed beetles, often mounted one upon another in copulation, are common to the leaves.
The natural history of milkweed illustrates in microcosm many of the interactions that affect larger ecological systems. Milkweed is adapted for long-distance pollination, dispersal, and defense. Its fauna demonstrate adaptation and specialization.
Why does the Monarch depend entirely on the milkweed as a host for its life cycle? Members of this butterfly family are called "milkweed butterflies" because as caterpillars they feed exclusively on plants in the milkweed family. Such a characteristic is not unusual among butterflies and moths - many butterfly and moth larvae feed exclusively on plants of a single family. Adult Monarchs feed on milkweed nectar, but not exclusively. Like the milkweeds, milkweed butterflies occur motly in the world's tropical regions. The most common milkweed butterfly in North America is the Monarch.
The question of why these caterpillars eat only milkweed leaves is related to the question of why other families of butterflies and moths are not found on milkweed. Also, why are both Monarch caterpillars and adult butterflies so boldly patterned and so colourful? Not only are adults bright and obvious, but they fly lazily and are seemingly easy targets for avian predators.
The answer to all of the above questions center on the fact that milkweed produces an abundance of a chemical called cardiac glycoside. The effects of consuming cardiac glycosides, of which digitalis (a drug obtained from Foxglove) is a common example, range from mild to severe poisoning. Cattle can easily become ill by eating milkweed. Cardiac glycosides are defense compounds that aid in protecting the plant from herbivores. Like cattle, most plant-eating insects cannot tolerate cardiac glycosides, but the milkweed butterflies (monarchs and their relatives) have evolved the ability both to tolerate and to store the toxic chemical in their tissues. Monarch caterpillars are as poisonous as the leaves they eat, protected by the same chemical defenses. The milkweed butterflies have turned an evolutionary trick on the milkweed - they can eat the plant without ill effects and then use its defense compound for their own defense! No other group of butterflies or moths has conquered this chemical defense so efficiently, so milkweed butterflies have exclusive access to milkweed. Their tolerance to cardiac glycosides permits them to become milkweed specialists.
Other milkweed specialists include the red Milkweed Beetle, which feeds on milkweed stems and roots, and the small Milkweed Bug, which eats milkweed seeds. Both insects are quite colourful and both are toxic to predators for the same reason as the Monarch - cardiac glycoside is stored in their tissues. |
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NinaM
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Petits Cochons
Edited by:NinaM
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| Everyone knows these seeds, along the roads, at fall. We used to play with them. |
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| Altered Image #1
NinaM
(4981)
The whole plant
Edited by:NinaM
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| Here is the Milkweed plant, seen in whole. You see the alternate leaves (in fact, I just noticed that they look like their cocoon!). |
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