And just like that, a female monarch butterfly fluttered into our Vacaville pollinator garden this morning, Aug. 10, and left a dozen or so calling cards: precious eggs.
We earlier saw a male monarch patrolling the garden on the morning of July 23, but he left to go find the girls.
So, total number of monarchs sighted in our garden so far this year: 2. (In 2016, we counted more than 300 eggs and caterpillars.)
Ms. Monarch deposited eggs on three milkweed plants: a narrow-leafed milkweed, Asclepias fascicularis, and two tropical milkweeds, Asclepias curassavica. She favored a lone tropical milkweed thriving in a planter. It's already attracted honey bees, leafcutter bees, syrphid flies, crab spiders, cabbage white butterflies, Gulf Fritillaries, mourning cloaks, gray hairstreaks, Western tiger swallowtails, ants, aphids, and a young praying mantis lying in wait.
Ms. Monarch totally ignored the showy milkweed, Asclepias speciosa, that towers over the garden. Not for me, she seemed to say. Ditto on the butterflyweed, Asclepias tuberosa.
We managed a few images of Ms. Monarch in flight, several images of her laying eggs, and a couple of the ever-so tiny eggs clinging beneath the leaves.
Welcome, Ms. Monarch. Now go tell all your buddies where to find the milkweed of your choice, and the rich nectar sources such as Mexican sunflowers (Tithonia rotunifola).
And you better warn them about that praying mantis...
Apparently so, from personal observation.
Over the years, we've grown multiple species of milkweed in our pollinator garden in Vacaville, Calif. We give them a choice. The species include:
- Narrow-leafed milkweed, Asclepias fascicularis
- Showy milkweed, A. speciosa
- Pleurisy root, A. tuberosa
- Tropical milkweed, A. curassavica
- Hairy balls or balloonplant, Gomphocarpus physocarpus
Which species do they prefer? Tropical milkweed, hands down. But it's a plant that's become highly controversial in California. Friends unfriend friends, and the unfriended lash out with how "bad" tropical milkweed is and how "uneducated" the messenger is. "Don't you know about Ophryocystis elektroscirrha (OE)?" they ask. "How dare you plant tropical milkweed? Yank it out!"
Meanwhile, the monarchs keep monarching. And we keep observing them.
Consider the male monarch spotted lying in the middle of a residential street in west Vacaville the morning of Jan. 3. It was there despite the rain, the cold and the passing cars. What will happen to it? Will it find a mate? Will its mate be able to find a milkweed to deposit her eggs? She certainly won't find native milkweed, such as A. fascicularis and A. speciosa, but she might find A. curassavica.
If. She. Is. Lucky.
Mona Miller, administrator of the educational Facebook page, Creating Habitat for Butterflies, Moths and Pollinators, recently shared a post that should be "food for thought" (for us) and that should result in "more food" (milkweed) for the monarchs. Her Facebook page focuses on "the preservation and protection of North American butterflies, moths and pollinators, particularly the Monarch butterfly."
"All milkweeds get Ophryocystis elektroscirrha (OE)," Miller wrote. "There are native milkweeds that are viable in the fall and winter. Tropical milkweed, due to their high level of toxins (cardenolides), are very medicinal. Monarch females choose tropical milkweeds over less toxic native plants to self-medicate. In October 2022, there was a discussion on the Monarch Watch email list. Dr. (Orley "Chip") Taylor (founder and director of Monarch Watch and a professor in the Department of Ecology and Evolutionary Biology at the University of Kansas) said that tropical milkweed does not stop the migration. He said more native and tropical milkweed should be planted. He said the more milkweed that is available the less spores will be left on all milkweeds. Fewer milkweeds leave monarchs visiting available milkweeds and leaving more spores. You can read the discussion here, there are several posts: https://lists.ku.edu/pip.../dplex-l/2022-October/012192.html."
"Actually, the best strategy is to plant more milkweeds, both native and tropical," Professor Taylor wrote, explaining that "First, the interactions between monarchs, milkweed and O.E. are frequency and density dependent. What this means is that spore loads on foliage are dependent on the abundance of milkweed relative to the number of ovipositing females. The O.E. infection rate is a function of this dynamic. Second, because of these relationships, O.E. cycles. That is, it increases and then declines only to increase again. There is a seasonal pattern to these cycles with low rates in the spring and higher rates about 3-4 generations. Third, the interactions that contribute to cycling involve spatial relationships that include distances between resources (milkweed patches) and the search capabilities of the butterflies. There is a time component as well."
"Here is the scenario that could play out from San Diego to Ventura counties and parts of Marin as well," Taylor wrote. "Due to warmer conditions more and more native milkweeds (mostly fascicularis) remain green during the winter. This appears to be happening over a broad area. With the sale of tropical milkweed (hereafter TM) being prohibited and homeowners being discouraged from growing TM, what is the likely outcome? With fewer milkweeds overall, the O.E. spore count will go up on both native and TM. OE will become more common rather than less. Further, the reduced distribution of milkweeds will reduce the opportunity for O.E. to cycle. Cycling depends on part of the milkweed distribution being relatively free of spores for the monarch population to recover. Overall, there will be fewer butterflies surviving the winter and therefore a lower starting population in the spring. If that happens, there will be fewer monarchs through the entire season. So, instead of leading to lower O.E. and more butterflies, the elimination of TM is likely to reduce the monarch population--in effect taking the butterflies away from the people. Again, in addition to cutting back TM from time to time to reduce O.E., an alternative solution is to grow TM and to see that it is hyper-dispersed in gardens, etc. through the 5-county area. The same strategy would involve A. fascicularis and other native milkweeds."
"Some of the reaction to TM is simply based on the notion that it is non-native," Taylor wrote. "We can agree on that point. However, it does not naturalize and therefore is not invasive. Our gardens are filled with such plants. TM supports populations of monarchs as far south as Peru and in most, if not all, places where monarchs have been introduced. Also, since this species flowers nearly continuously through the growing season, it is a source of nectar for a large number of pollinating species. TM supports monarchs--full stop! Let's learn to live with it. More milkweeds equal more monarchs and less O.E. overall."
Taylor went on to say that TM does not cause monarchs to break diapause and become reproductive. "Dingle suggests that it is temperature that causes monarchs to break diapause and that is exactly what I have been saying for years. Hormone production is a function of temperature--head temperatures--and not contact with plants. The major driver in the West has been and will continue to be weather/climate. It starts with the conditions that determine the size and distribution of the overwintering female numbers and their reproductive success."
However, the California Department of Food and Agriculture (CDFA), influenced by conservation groups, has categorized A. curassavica as "a noxious weed," and county agricultural commissioners have banned the sale of the plant in nurseries in Marin, Contra Costa, San Mateo and Ventura counties.
Professor Dingle bears to differ. "No one should rush out and pull out their tropical milkweed as it would be a waste of time and effort," he says. "Nurseries should also be able to continue to sell it." He points out:
- "There is not enough tropical milkweed planted to have much influence (see the amount of A. syriaca and A. fascicularis throughout the American west not to mention various other species like A. erosa, cordifolia, californica, etc.) Yes, there are parasites on A. curassavica as there are on ALL milkweeds."
- "There are populations of monarchs that are doing just fine feeding exclusively on A. curassavica (e.g. on many Pacific Islands, such as Guam where I have studied them.
- "Migration and the diapause that accompanies it in the fall are determined by shortening photoperiod and temperature (warm temps can override short days hence the issue with climate change). There is no significant influence of food plant."
UC Davis distinguished professor Art Shapiro, who has monitored butterfly populations in central California since 1972, says the "anti-curassavica propaganda is total hogwash. I have been saying so for years."
Curious, isn't it, that a plant can be so controversial? Four states, California, Arizona, New Mexico and Texas, border Mexico. On the California side, inches away from the Mexican border, tropical milkweed is considered a "noxious weed" per the CDFA definition. On the other side, in Mexico, it's simply a great host plant for monarchs.
What does 2023 hold for the iconic monarch and its host plants? For one thing, more scientific research is needed.
In stunning images, the Bohart Museum display depicts the complete metamorphosis of the monarch: from egg to larva to pupa to adult.
It's the work of Larry Snyder of Davis, who for several years photographed a UC Davis professor's research project on wild monarch-native milkweed interactions in the North Davis Channel of rural Davis. Snyder is a retired music teacher, vocal accompanist, and piano and harpsichord technician.
We wrote about the monarch-milkweed project on the UC Davis Department of Entomology and Nematology website on July 28, 2022.
Professor Louie Yang, the principal investigator of the research project, organized and led a 135-member team, all co-authors of the paper, “Different Factors Limit Early- and Late-Season Windows of Opportunity for Monarch Development,” published in the journal Ecology and Evolution. (This document is open access at https://bit.ly/3volFaI.)
From 2015 through 2017, the team monitored the interactions of monarchs, Danaus plexippus, on narrow-leafed milkweed, Asclepias fascicularis, planted in December 2013 on city-owned property adjacent to the North Davis irrigation channel.
The project, funded by two of Yang's National Science Foundation grants, involved UC Davis, Davis Senior High School and the Center for Land-Based learning. Among them were 107 high school students and a K-12 teacher, 18 UC Davis undergraduate students, three graduate students and two post-graduate researchers.
Unfortunately, a City of Davis maintenance crew unintentionally mowed the site on May 5, 2017, “damaging several plants in this population," Yang related. "However, most plants in the population were below the height of the mower blades at this point in the growing season.”
Today the milkweed population at the North Davis Channel is being maintained by the City of Davis and dedicated citizens, including Larry Snyder.
From music to milkweed to monarchs...it's been quite a journey.
The work of Professor Yang's MMMILC crew fascinated him, and the site became his "adopted back yard." At first, Snyder just watched, then he began photographing "the insect life on the plants." At the end of the project's official monitoring period, he "secured the cooperation of city staff" so he could continue maintaining the milkweeds without the loss of spring growth to the annual fire-suppression mowings.
Snyder says he "especially enjoys watching insect behavior and interaction, both within and between species and in relation to the host plants, as well as tracking how individual populations change during the seasons and from year to year."
"I am most grateful to the Bohart Museum and the frequent assistance of their remarkable staff and associates," Snyder said.
The Bohart Museum, founded in 1946, is directed by Lynn Kimsey, UC Davis distinguished professor of entomology. It is the global home of eight million insect specimens, as well as the live "petting zoo" and an insect-themed gift shop stocked with t-shirts, hoodies, books, posters, jewelry, collecting equipment and more. Named for UC Davis professor and noted entomologist Richard Bohart, it is open to the public from 8 a.m. to noon, and 1 to 5 p.m., Mondays through Thursdays. More information is available on the website at https://bohart.ucdavis.edu or by contacting email@example.com./span>
It's early morning, Aug. 20. A lady beetle is snacking on aphids on our native milkweed plant (where the monarchs are supposed to be, but aren't!). And then, apparently satiated, LB climbs a twig to the top of her Mt. Everest, looks around, unfolds her wings, and takes off.
The miracle of flight! The miracle of unpacking what's under those wings. The miracle of seeing it all happen.
"The ladybug is a tiny insect with hind wings four times its size," wrote Joanna Klein in her article,
Ladybugs Pack Wings and Engineering Secrets in Tidy Origami Packages, in the May 18, 2017 edition of The New York Times. "Like an origami master, it folds them up into a neat package, tucking them away within a slender sliver of space between its abdomen and the usually polka-dotted, harder wings that protect it.
"When it is time to take off, it deploys its flying apparatus from beneath its colorful shell-like top wings, called the elytra, in only a tenth of a second. And when it lands, it folds it back in just two. Switching between flying and crawling many times in a day, the ladybug travels vast distances."
Klein called attention to a study published in the May 17, 2017 edition of the Proceedings of the National Academy of Sciences. The authors, she said, detailed "just how the ladybug manages to cram these rigid structures into tiny spaces is a valuable lesson for engineers designing deployable structures like umbrellas and satellites."
It's the work of Kazuya Saito of the Institute of Industrial Science, University of Tokyo, Japan, and his colleagues, Shuhei Nomura, Shuhei Yamamoto, Ryuma Niiyama and Yoji Okabe.
The title? "Investigation of Hindwing Folding in Ladybird Beetles by Artificial Elytron Transplantation and Microcomputed Tomography."
The significance? "Hindwings in ladybird beetles successfully achieve compatibility between the deformability (instability) required for wing folding and strength property (stability) required for flying. This study demonstrates how ladybird beetles address these two conflicting requirements by an unprecedented technique using artificial wings. Our results, which clarify the detailed wing-folding process and reveal the supporting structures, provide indispensable initial knowledge for revealing this naturally evolved optimization system. Investigating the characteristics in the venations and crease patterns revealed in this study could provide an innovative designing method, enabling the integration of structural stability and deformability, and thus could have a considerable impact on engineering science."
The abstract? "Ladybird beetles are high-mobility insects and explore broad areas by switching between walking and flying. Their excellent wing transformation systems enabling this lifestyle are expected to provide large potential for engineering applications. However, the mechanism behind the folding of their hindwings remains unclear. The reason is that ladybird beetles close the elytra ahead of wing folding, preventing the observation of detailed processes occurring under the elytra. In the present study, artificial transparent elytra were transplanted on living ladybird beetles, thereby enabling us to observe the detailed wing-folding processes. The result revealed that in addition to the abdominal movements mentioned in previous studies, the edge and ventral surface of the elytra, as well as characteristic shaped veins, play important roles in wing folding. The structures of the wing frames enabling this folding process and detailed 3D shape of the hindwing were investigated using microcomputed tomography. The results showed that the tape spring-like elastic frame plays an important role in the wing transformation mechanism. Compared with other beetles, hindwings in ladybird beetles are characterized by two seemingly incompatible properties: (i) the wing rigidity with relatively thick veins and (ii) the compactness in stored shapes with complex crease patterns. The detailed wing-folding process revealed in this study is expected to facilitate understanding of the naturally optimized system in this excellent deployable structure."
But back to our little lady beetle in our pollinator garden. It's difficult to catch a lady beetle in flight. They don't fly when you WANT them to, and when they do fly, you and your camera are NOT ready. And when you and your camera ARE ready, all focused and everything, they change their mind or change directions. So, in keeping with our motto, "Don't poke 'em, prod 'em or pin 'em," we waited.
With the morning sun behind her back, LB finally obliged and took flight.
We managed to catch the action with a Nikon Z7 with a Nikon 105mm lens, manually focused: F-stop 16; shutter speed, 1/2500 of a second; and ISO, 5600.
Here's hoping LB will return. She missed a few aphids!
The narrowleafed milkweed, Asclepias fascicularis, beckons monarch butterflies (the host plant), aphids, praying mantids and assorted other insects, but once in a while, you'll see a leafcutter bee. Both the plant and the bee are natives.
This male bee (below) spent the afternoon patrolling for females, but it rested in between.
It's a dangerous place to rest when there's a predator (praying mantis) around, but all ended well.
Leafcutter bees, spp., so named because the females cut leaves and petals (perfectly round holes!) to line their nests, are smaller than honey bees--and much faster. They're easily recognizable by the black-white bands on their abdomen.
The females do all the work. They gather pollen and nectar, make the nests from the leaf and petal fragments, and lay eggs. They seal the egg chambers with the leaves or flower petals.
The male's job is to reproduce. And sometimes, you'll see one sunning itself on a milkweed leaf.
Of the 4000 bee species known in the United States, about 1600 reside in California. The leafcutter bee is just one of them. The family, Megachilidae, includes these leafcutting bees, Megachile angelarum, M. fidelis and M. montivaga; the alfalfa leafcutting bee, M. rotundata; the Mason bee, Osmia coloradensis; and the blue orchard bee (BOB), Osmia lignaria propinqua.
For more information on California's bees, read California Bees and Blooms: A Guide for Gardeners and Naturalists (Heyday), the work of UC-affiliated scientists,/span>