Monarch on a thistle—how beautiful! We’ve heard that the biggest threat to Monarch butterflies is loss of habitat where they overwinter in Mexico. And we’ve heard that feeding on milkweed renders Monarchs toxic to predators (which they signal with bright yellow and black stripes). In Bernice’s story, below, this week we learned Monarchs are not as safe from predators as we’d thought.
Kindly neighbor Bobi Thornhill found ten Monarch caterpillars eating the last leaves of her four milkweed plants, and asked if I had milkweed to which she could transfer them. She brought five and deposited them on two plants near our terrace. Her research said they were of a size—25-45mm long—to begin pupating (https://monarchlab.org/biology-and-research/biology-and-natural-history/breeding-life-cycle/life-cycle/#larva).
I photographed them; then, before leaving for errands in Charlottesville, checked back: Three quietly nibbling, one moving along the ground under the milkweed, one missing—and a shifty-looking Chinese (aka “praying”) mantis prowling among the leaves. Suspicious, I chased the mantid off the plant and it sprinted to the other side of the terrace. (Had I realized, definitely, that some mantids will eat Monarch butterflies in all their life stages, I would have captured and moved it to the vegetable beds.)
Late in the afternoon when I returned, only one caterpillar remained on the milkweed, and next morning it was still there, chomping away. The others? Pupating somewhere out of sight? Or eaten?
Curious, I went online to learn more about Monarch predators. Most birds avoid them, but ants, spiders and certain wasps will feast on eggs and larvae: (https://monarchlab.org/biology-and-research/biology-and-natural-history/parasites-natural-enemies/) And, I found that mantids are able to avoid the most toxic parts while eating the caterpillars: (http://phenomena.nationalgeographic.com/2013/01/25/chinese-mantis-guts-its-toxic-caterpillar-prey/).
To give the remaining caterpillar a better chance, I wrapped the plant and adjacent rose support with the close-woven plastic shade cloth I keep for sheltering lettuce seedlings in late summer—making the metamorphosis, if not unassailable, at least inconvenient.
Next morning, we had a J-shaped caterpillar hanging from the top of the tuteur and, by late afternoon, a shiny green pupa in its place. Having learned that this generation of monarchs—the summer’s fourth—is the one that will fly to warmth for the winter, hibernate, and return in spring to restart the cycle, I was excited at the prospect of seeing this one off.
Next morning, thinking the heavy shade a bit unnatural, I partly opened the covering.
Following morning: Pupa gone!
Another friend, Master Gardener Pat Chadwick, said she had 45 monarch caterpillars disappear from her swamp milkweeds in a matter of hours last week.
Now I understand why Monarchs lay so many eggs, and why some enthusiasts cut milkweed and move them inside to pupate. For now, we’re hopeful and on the alert for any Monarchs that made it.
Thanks to Bobi Thornhill for, if not butterflies, certainly a learning opportunity.
The Quarry Gardens are glowing right now with 14 species of goldenrod in various stages of bloom. If that seems like a lot, know that solidago, or goldenrod, is a genus of 100–120 species of flowering perennial plants in the aster family (Asteraceae), and most may be found in North America.
The most prominent species at the overlook platform is Gray goldenrod, Solidago nemoralis, seen above and in the highlight photo.
Nine species are QG legacies—found here in the pre-garden surveys of biota. Among those legacies is Pineywoods or Small’s goldenrod, Solidago pinetorum, pictured below, about 3 feet tall, discovered only weeks ago as a volunteer along the walk from the Visitor Center through the pine woods—a Nelson County first.
Other legacy goldenrods:
- Tall goldenrod,Solidago altissima, (to 4 feet)
- White goldenrod, Solidago bicolor
- Blue-stemmed goldenrod, Solidago cassia
- Slender goldenrod, Solidago erecta
- Gray (or Field) goldenrod,Solidago nemoralis
- Anise-scented goldenrod, Solidago odora
- Stiff goldenrod,Solidago rigida var. rigida
- Wrinkle-leaf goldenrod, Solidago rugosa
The Slender goldenrod at left is definitely a legacy but the Stiff goldenrod at right, found in the overlook prairie, might have sneaked in with purchased seeds of other plants.
New to the site are five more species—native to the immediate area—that Rachel and her CUH crew have added:
- Early goldenrod, solidago juncea, greets visitors from the prairie planting at the entrance gate.
- Showy goldenrod, Solidago speciosa, may be found among the thousands of plants in the prairie over the original filled-in quarry pit between the two quarry pools.
- Stout goldenrod, Solidago squamosa, is in the North Quarry’s waterside pollinator patch.
- Zig-zag goldenrod, Solidago flexicaulis,may be found in the dry shade near the Whispering Waters
They are often difficult to distinguish from one another
Goldenrods are among the most important late-season pollinator plant. Honeybees collect the nectar for winter, and other bees use the pollen to supply late-season nests.
No honeybees in this photo, but at least a dozen species of bees and wasps were working the plants when it was taken.
Here are some things from Wikipedia of interest about goldenrod:
- Although frequent handling of goldenrod and other flowers by florists can cause allergic reactions, goldenrod is inaccurately blamed for hay fever: the blame for that lies with the ragweed that often grows in proximity and blooms at about the same time.
- Goldenrod does make a spicy honey, but it sometimes has a rank odor and taste until fully processed (by bees). It is not a big commercial success, but apparently has its followers.
- Thomas Edison and Henry Ford experimented with growing goldenrod for its rubber content before and during World War 2, anticipating a need for synthetic rubber. Ford even gave Edison a Model T with tires made of it in late 1920s. After Edison died in 1931, Ford enlisted the aid of Washington Carver, a well-known agronomist, and they succeeded in producing a hybrid goldenrod that yielded as much as 12 percent rubber. Unfortunately, it was not very good rubber, and by the time that first Carver and then Ford died by 1947, the project was abandoned.