Monarch Butterflies in Trouble
For several years we have been in the midst of a milkweed craze across the United States. Monarch butterflies (Danaus plexippus) are particularly beautiful and the media has written extensively about the enormous drop in their population. Monarch larvae feed exclusively on the highly toxic milkweed leaves causing nature lovers to plant milkweed in an effort to stimulate population growth. I had also joined this worthwhile effort although with little success until recently.
So Many Milkweeds
For each of the last several years I have bought one mature milkweed plant and then watched it languish and die. Although there are 72 species of native milkweed in the United States, ~90% of Monarch butterflies prefer the Common Milkweed (Asclepias syriaca).
Strange to say, the first milkweed that actually grew in my garden two years ago was a Swamp Milkweed (Asclepias incarnata L). And the chosen flower bed was no swamp! Then this year some Common Milkweed has popped up although in a completely different part of the garden.
Another popular milkweed is the Butterfly Weed –Asclepias tuberose with its bright orange flowers although its sap is not toxic. Butterflies and other pollinators feast on the flowers’ nectar.
Despite the fact that the majority of the milkweed family contains toxic cardiac glycosides, the plant has been used medicinally for centuries. The scientific name –Asclepias – referring to the ancient Greek god of medicine, – hints at its medicinal usage. The sap is the most toxic part of the plant followed by the stem, leaves and roots. While the sap has been used for wart removal, the other parts of the plant have also been used, but only after various treatments to remove the toxins. Needless to say, no one without training should ever attempt to self-medicate with plant extracts.
Choosing Plant Names
The species’ names are also interesting. Tuberosa indicates that the root is tuberous meaning having a thickened underground part of the stem that is knobby with swellings. Incarnata comes from the Latin carn meaning “flesh” and atus meaning “like”. Since the flowers are dusty pink it was said to be flesh-like or flesh-colored. The syriaca species’ designation is seemingly quite strange since the plant is native to the United States. Linnaeus, for some reason, mistakenly thought the plant was native to Syria when he classified it.
What Have We Here!
In any case, the swamp milkweed was the more robust of the two milkweeds in my garden. Therefore, I found myself regularly checking on it. One day, I was surprised to see that the stem had turned completely orange. As I came closer and took off my glasses to see better, it became clear that the orange was not from the stem but, rather, that the stem was covered entirely with tiny orange bugs.
Mystery Insect
Mystified, I was not sure how to identify these insects. Enter “Google Lens.” For those not familiar with it – as I was not until a helpful friend revealed this wonderful option – it’s a way for Google to identify almost anything that can be photographed by comparing the photo to its worldwide data-base. Inside of a minute, I learned that my tiny creatures were oleander aphids (Aphis nerii).
These aphids are remarkable in that they all are female, are born pregnant, and give birth to live young (viviparity) The nymph, as the newly born insect is called, develops through five stages before becoming an adult. In this way, in fact, all of the insects are clones of one another.
It will come as no surprise that the aphids are found on oleander shrubs as well as other members of the dogbane family known scientifically as Apocynaceae. What is most interesting is that most of the species that host the oleander aphids contain toxic compounds including cardiac glycosides.
There have been a few Monarch butterflies visiting my garden in the last two weeks. So far, I have not spotted any egg sacs on the underside of the common milkweed leaves. I intend to keep checking.
Sura Jeselsohn is the author of “A Habit of Seeing: Journeys in Natural Science.”
Good to hear from you. I’ve moved to Maplewood Park Place, a CCRC (Continuing Care Retirement Community) not far from where I was before and it’s been a great move and the right decision. All is well with us. How are you doing?