- Author: Kathy Keatley Garvey
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.
![A monarch caterpillar feeding on tropical milkweed, Asclepias curassavica, in Vacaville, Calif. (Photo by Kathy Keatley Garvey) A monarch caterpillar feeding on tropical milkweed, Asclepias curassavica, in Vacaville, Calif. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/96925.jpg)
![A monarch nectaring on tropical milkweed, Asclepias curassavica, in Vacaville, Calif. (Photo by Kathy Keatley Garvey) A monarch nectaring on tropical milkweed, Asclepias curassavica, in Vacaville, Calif. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/96926.jpg)
![Honey bees and other pollinators frequent tropical milkweed, Asclepias curassavica. (Photo by Kathy Keatley Garvey) Honey bees and other pollinators frequent tropical milkweed, Asclepias curassavica. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/96928.jpg)
- Author: Kathy Keatley Garvey
It looked newly emerged but it wasn't moving.
In fact, it looked quite dead.
A gloved hand quickly rescued the monarch, a male, from passing traffic.
A monarch in January? Here in Vacaville after heavy rain and flooding and more on the way? "A third atmospheric river storm," National Public Radio (NPR) announced Jan. 2, "is set to add to misery in California's flooded areas. Forecasters in Northern California have a sobering new-year message for people who are reeling from floods and mudslides: the situation could get worse before it gets better."
"Much like the end of 2022 storm, this will be a strong wind event along with moderate to heavy rainfall," according to the National Weather Service.
Rain, floods, and recent freezing temperatures....
So how incredible to find a monarch here in January, while its "clan" is clustering in overwintering spots along the California coast. (They won't be heading inward until around February.)
"How long has it been seen you saw Monarchs flying in your area?" asked Mona Miller, who administers the popular Facebook page, Creating Habitat For Butterflies, Moths, & Pollinators. "Another option is that if it found a microclimate, which protected its cycle it has been slowly finishing its cycle. With climate change and fluctuating temperatures, I have been seeing late Monarchs surviving several frosts. Once they make it to adults, fall to winter Monarchs become more cold tolerant. This cold tolerance is rapid and protects them from fluctuating temperatures caused by climate change."
The last monarch I saw flying in Vacaville was on Oct. 26, 2022. It was a male that stopped to nectar on our Mexican sunflower (Tithonia rotundifola). The blooms are long gone. We're in the dead of winter.
But there's hope.
"The ongoing wild windy wet weather in California is the wild card that interferes with predictions about the summer population in 2023," James commented. "Wild late winter storms are likely what caused the substantial reduction (from ~ 200,000 to 30,000) in western monarch numbers back in 2018/19. These lower numbers then led to the ultra-low number in 2020 of 1899 overwintering butterflies. Then of course we rebounded to more than 247,000 in 2021 and likely more than 300,000 for Nov 2022."
"The question now," James said, "is will the current storms and any others that occur during January-February, savagely dent the population as the 2018 storms did? If the overwintering population can survive the storms without major losses, then I think we will see a good-sized summer population in California and the Pacific Northwest in 2023." He administers the Facebook page, Monarch Butterflies in the Pacific Northwest.
It's sponsored by the Western Monarch Advocates (WMA) and is open to all interested persons--from scientists to citizen scientists to monarch aficionados. It will include networking, field trips, and meals.
James, a WMA board member, will be among the keynote speakers from four countries. The event is billed as "an exchange of ideas from across the Western States, Tribal Lands, Mexico, Canada and Australia-all with an interest in our western monarch population! Expand your knowledge and make connections with other Monarch enthusiasts, researchers, and conservation organizations."
As they point out, "our migrating Western Monarch butterflies do not stop at state or international borders; nor should our efforts to restore them."
And, apparently, the Vacaville monarch lying cold and still on a residential street on Jan. 3 didn't let the rain, the storm and the floods--or passing cars--stop him from surviving. He also avoided the hungry birds seeking a fast-food meal (birds learn quickly that monarchs "don't taste good").
He's alive.
Monarchs continue to inspire and surprise us.
![A gloved hand holds a male monarch found cold and still in the middle of a residential street in west Vacaville on Jan. 3, 2022. (Photo by Kathy Keatley Garvey) A gloved hand holds a male monarch found cold and still in the middle of a residential street in west Vacaville on Jan. 3, 2022. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/96901.jpg)
![A male monarch nectars on Mexican sunflower (Tithonia rotundifola) in Vacaville, Calif., on Oct. 26, 2022. (Photo by Kathy Keatley Garvey) A male monarch nectars on Mexican sunflower (Tithonia rotundifola) in Vacaville, Calif., on Oct. 26, 2022. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/96907.jpg)
- Author: Kathy Keatley Garvey
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 bmuseum@ucdavis.edu.
/span>![Larry Snyder's monarch photography display in the hallway opposite the entrance to the Bohart Museum of Entomology, Academic Surge Building. Larry Snyder's monarch photography display in the hallway opposite the entrance to the Bohart Museum of Entomology, Academic Surge Building.](https://ucanr.edu/blogs/bugsquad/blogfiles/95899.jpg)
- Author: Kathy Keatley Garvey
Fact: Without milkweed, no monarchs.
Yet a milkweed species that's been thriving in California for more than a century is getting a bad rap. The California Department of Food and Agriculture (CDFA), apparently influenced by conservation groups, has categorized Asclepias curassavica, commonly known as tropical milkweed, as "a noxious weed."
That means, among other things, that county agricultural commissioners can ban the sale of tropical milkweed in nurseries. Indeed, several counties, including Marin, Contra Costa, San Mateo and Ventura, already have.
Banned for sale in nurseries? Says entomologist Jeff Smith, who curates the Lepidoptera collection at the Bohart Museum of Entomology: "There are PLENTY of other 'noxious' weeds sold in nurseries (eucalyptus?) that don't seem to raise the hackles of these counties, so it appears more political than factual, and coming up with the supposed pathogens-on-the-plants scenario looks like they searched for an excuse."
Fact: Infected monarch butterflies can deposit microscopic protozoan parasites, Ophryocystis elektroscirrha or OE, on milkweed. That's ALL species of milkweed, not just tropical. Tropical, however, does not die back in the winter in some parts of California, and that, some argue, encourages monarchs to continue to breed and impedes their migration to overwintering sites. Some blame this "continued OE exposure" to the decline of the monarch population.
Hugh Dingle, distinguished professor emeritus of entomology, behavior and evolution at UC Davis and now a Marin County resident, is an internationally known expert on animal migration. He's researched animal migration for some 50 years. In the last 20 years or so, he has focused on monarch butterflies. He has authored two editions of Migration: The Biology of Life on the Move and some 100 papers. National Geographic featured Professor Dingle in its cover story on “Great Migrations” in November 2010. LiveScience interviewed him for its November 2010 piece on “Why Do Animals Migrate?” (See news story that includes his biographical information)
Professor Dingle responded to a recent front-page article in a Marin County paper about the ban on tropical milkweed. Banning tropical milkweed will NOT save the monarch, Dingle told the reporter in an email. In fact, he said, the ban will "essentially have zero effect on monarchs" and "no one should rush out and pull out their tropical milkweed as it would be a waste of time and effort. Nurseries should also be able to continue to sell it."
The contents of his email, which the professor shared with Bug Squad, include:
- "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."
They Should Know Better! Dingle said some of the advice that CDFA received to categorize A. curassavica as a "noxious weed" came from conservation groups. "They should know better!" he declared.
Art Shapiro, UC Davis distinguished professor of evolution and ecology, has been researching the butterfly populations (including monarchs) of central California for more than 50 years. He co-authored the well-cited research article, "Understanding a Migratory Species in a Changing World: Climatic Effects and Demographic Declines in the Western Monarch Revealed by Four Decades of Intensive Monitoring," published online in March of 2016 in the journal, Population Ecology.
Professor Shapiro shared this email with Bug Squad:
So, What Happened? We asked Professor Dingle how tropical milkweed went from total acceptance to a bad reputation. "I don't know why tropical milkweed got such a bad reputation," he responded in an email. "A couple of possibilities: in some places tropical milkweed seems to have more of the Oe parasite than temperate species which die back in winter--ergo, butterflies pick up more parasites (Fact is not enough to have much influence on migration or breeding although in some places there can be a little. But over the whole range of monarchs . . .naaah!) Second possibility is since tropical is around longer, butterflies can feed on it longer and so might 'keep butterflies from migrating.' BUT...migration is a photoperiodic phenomenon (occurs with short days) so feeding is irrelevant. Besides during migration monarchs will feed on almost any plant with nectaring flowers!"
"Monarch butterflies are dependent upon milkweed as its host plant. They lay their eggs on milkweed and their caterpillars eat milkweed. In the past, monarchs in California spent the winter roosting in trees along the coast of California. They did not breed during the winter. They moved inland during summer months where they bred."
"Because of global warming, monarchs have begun to breed during the winter months in California and the existence of tropical milkweed in gardens in coastal California has made that possible...The Nature Police have succeeded in getting the sale of tropical milkweed banned in Contra Costa, Marin, San Mateo and Ventura counties. Academic entomologists have pushed back against this harmful ban in an article published by The Monterey Herald, San Jose Mercury, Marin Independent Journal, and East Bay Times.
The milliontrees.me website also points out that:
- Hugh Dingle, a retired University of California at Davis entomology professor who has studied monarch butterfly migration for more than two decades, said the bans are “basically a wasted effort” and that the focus should be on larger threats such as pesticide and herbicide use. All species of milkweed carry parasites that can affect monarch populations."
- “Arthur Shapiro, a UC Davis professor who has studied monarch butterflies for the past six decades, described the rationale behind the bans as “hogwash.” Shapiro, Dingle and other researchers said winter breeding among monarch butterflies is a relatively new behavior and one influenced by warmer winter temperatures caused by climate change.”
- “David James, an associate entomology professor at Washington State University who has studied monarch butterfly breeding and migration in the Bay Area, said there is a case to be made about the tropical milkweed as being a vital resource for the monarchs in a changing climate.”
- “Leslie McGinnis, a UC Berkeley doctoral candidate studying monarch populations and working with gardeners in the East Bay, said the bans take a 'simplistic view' of the threats that monarchs face, including the fact that many native milkweed plants supplied to nurseries can also be sprayed with pesticides. The bans, she said, can work to disenfranchise or demonize people that have tropical milkweed who instead could be partners in working to help restore monarch populations.”
Indeed, the website minces no words: "Native plant advocates are wedded to a past that is long gone. The climate has changed and it will continue to change. Monarchs and other animals are trying to adapt to the changed conditions. Their survival depends on their ability to adapt. The native plant movement has become a form of climate change denial. Their irrational hatred of introduced plants is damaging the environment with herbicides and harming wildlife. There is no evidence that tropical milkweed is harmful to monarchs."
Mona Miller, who administers the popular Facebook page, Creating Habitat For Butterflies, Moths, & Pollinators, related in a recent post: "Monarch are resilient insects, they have so many strategies to increase their population, but they do have their limits. We must stop pulling out tropical milkweed and cutting it back. Washing off all milkweed should suffice to clean off the OE spores. I emailed several scientists, no one could tell me that OE (Ophryocystis elektroscirrha is a protozoan parasite) has any way to attach to milkweed leaves other than getting caught in the hairs. Tropical milkweed has smooth leaves. Tropical milkweed has been in California since 1909, that is over 100 years. Totally eradicating tropical milkweed, just like totally eradicating all the eucalyptus trees, would have a detrimental effect on the monarch population, perhaps it already has." (Both eucalyptus and tropical milkweed are non-natives.)
Personal Experience. As an aside, our family has provided several species of milkweed in our pollinator garden in Vacaville for more than a decade. The species now include narrowleaf milkweed, A. fascicularis; butterflyweed, A. tuberosa; showy milkweed, A. speciosa; and tropical, A. curassavica. One season we counted more than 300 eggs and caterpillars on the milkweed. Almost all favored A. curassavica. Second choice: A. fascicularis. Some scientists say that perhaps tropical milkweed offers more toxins, and monarchs "know what they want and need."
We continue to plant both natives and non-natives in our thriving garden. The practice now seems so highly controversial that sometimes we feel as if we must mark ourselves "safe" from negativity. But as Professor Shapiro told Bay Nature in June 2022: "I am sick to death of being told you must use natives, especially if a butterfly has no more interest in it than a fire hydrant."
Additional Resources:
- Milliontrees.me:
The Consequences of Putting Plants into 'Native' Strait-Jackets - "Monarch Butterfly Experts Fault Marin Tropical Milkweed Ban," published in, among others:
Ukiah Daily Journal
Marin Independent Journal
Chronicles Live - Xerces Society of Invertebrate Conservation
Monarchs in Decline
Native Milkweeds - Bug Squad:
What's Happening with Our Western Monarch?
![A monarch nectaring on tropical milkweed, Asclepias curassavica.(Photo by Kathy Keatley Garvey) A monarch nectaring on tropical milkweed, Asclepias curassavica.(Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/95406.jpg)
![A monarch caterpillar foraging on tropical milkweed, Asclepias curassavica. (Photo by Kathy Keatley Garvey) A monarch caterpillar foraging on tropical milkweed, Asclepias curassavica. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/95407.jpg)
![Close-up of a monarch caterpillar. (Photo by Kathy Keatley Garvey) Close-up of a monarch caterpillar. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/95408.jpg)
![A monarch laying an egg on a tropical milkweed. (Photo by Kathy Keatley Garvey) A monarch laying an egg on a tropical milkweed. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/95412.jpg)
- Author: Kathy Keatley Garvey
Never be late for dinner or it might be all gone.
Take the case of the Mexican sunflowers, Tithonia rotundifola, that we planted last April for the monarchs. Monarchs seem to favor Tithonia more than any other nectar source in our pollinator garden. Second choice: the butterfly bush, Buddleia davidii.
May, June, July, and August came and went. The invited (and expected) guests were a "no show." Didn't they make reservations? Or did they forget?
The Tithonia drew honey bees, long-horned bees, syrphid flies, a praying mantis, and assorted butterflies. No monarchs.
In September, entomologist David James of Washington State University, who studies migratory monarchs, announced the monarchs are on their way from the Pacific Northwest to their overwintering sites along coastal California. "They're coming," he said.
Finally, on Sept. 16, a single monarch glided in, sipped some nectar on the Buddleia for a few seconds and left. Another monarch stopped by on Sept. 26, nectared on the Tithonia for a couple of seconds and vanished.
Where are all the dinner guests?
Finally, at 4:30 p.m. on Oct. 3, a male monarch arrived for dinner. And what a 12-course dinner it was on the Tithonia's remaining 12 flowers. He paused once to sample nectar from the Buddleia, but he obviously preferred the Tithonia.
Frankly, it's not been a good year for monarchs in our pollinator garden. Monarchs totally ignored the milkweed, their host plant, and almost disregarded the nectar sources. In comparison, back in 2016, monarchs laid about 300 eggs on our milkweed. In the migratory season, it was not uncommon to see seven monarchs in our garden at one time.
If any more monarchs arrive, they'll not get much Tithonia or Buddleia to fuel their flight to the overwintering sites. They'll have to settle for what's left of the nectar sources: African blue basil, catmint, lion's tail, Mexican petunia, and honeysuckle.
We're just glad one dinner guest showed up, although he was almost too late for dinner.
![A male monarch arrives Oct. 3 to nectar Mexican sunflower, Tithonia rotundifola, in a Vacaville pollinator garden. (Photo by Kathy Keatley Garvey) A male monarch arrives Oct. 3 to nectar Mexican sunflower, Tithonia rotundifola, in a Vacaville pollinator garden. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/95307.jpg)
![Close-up of a male monarch nectaring on Mexican sunflower, Tithonia rotundifola. (Photo by Kathy Keatley Garvey) Close-up of a male monarch nectaring on Mexican sunflower, Tithonia rotundifola. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/95308.jpg)
![A spent blossom hangs over a male monarch that is sipping nectar from a Mexican sunflower, Tithonia rotundifola. (Photo by Kathy Keatley Garvey) A spent blossom hangs over a male monarch that is sipping nectar from a Mexican sunflower, Tithonia rotundifola. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/95309.jpg)
![The male monarch samples nectar from a butterfly bush, Buddleia davidii. (Photo by Kathy Keatley Garvey) The male monarch samples nectar from a butterfly bush, Buddleia davidii. (Photo by Kathy Keatley Garvey)](https://ucanr.edu/blogs/bugsquad/blogfiles/95310.jpg)