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>
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."
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
- Xerces Society of Invertebrate Conservation
Monarchs in Decline
- Bug Squad:
What's Happening with Our Western Monarch?
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.
Be on the lookout for migratory Monarch butterflies from the Pacific Northwest heading south to their overwintering sites along the California coast.
It's been a very good year for Monarchs in the Pacific Northwest (PNW), according to noted entomologist and Monarch researcher David James, an associate professor at Washington State University (WSU), Pullman.
"The numbers we are seeing in the PNW this summer are consistent with numbers I've seen in summers past when the overwintering population was approximately 250,000 as it was last winter," he wrote in an email Aug. 31.
"I have been compiling all the PNW monarch reports I have come across this summer--as I have done for many summers in the past. These have been from iNaturalist, Journey North, various Monarch Facebook pages and personal communications I get many people telling me they've seen a monarch. I verify all reports, that is, they must have a photo, or I know the reporter is experienced."
"Last summer (2021) I verified approximately 60 Monarch sightings in the PNW. This summer, I have had approximately 500 verified reports. "So, I think we have seen an 8-10 fold increase in Monarch numbers this summer in the PNW. The majority have been in Oregon, followed by Idaho, Washington and British Columbia. There are also positive reports of good numbers of Monarchs in Utah, Nevada and eastern California."
"So the signs are there for a good migration back to California this fall," James said. "The big question will be whether the migrants proceed normally to the overwintering sites or whether they do what they did in 2020, establish winter breeding populations in slightly inland places like San Francisco and Los Angeles. The determining factor will be the temperatures California experiences over the next six weeks. If average temperatures prevail, then the butterflies will go to the coastal overwintering sites and we will have--I think--spectacular numbers again...at least as high as last year and possibly much higher."
To track migratory Monarchs, citizen scientists in the David James' research program affix a tag on the discal cell (underside of the hind wing). The tag does not interfere with its flight.
This year James handed out 2000 tags to citizen scientists in southern Oregon.
One of his citizen scientists, Steve Anderson of Ashland, Ore., tagged a male Monarch on Aug. 28, 2016 that stopped for nectar in our Vacaville pollinator garden on Sept. 5, 2016. The tag read “Monarch@wsu.edu A6093." It hung around for five hours. (See Bug Squad blog and WSU news story)
"So, assuming it didn't travel much on the day you saw it, it flew 285 miles in 7 days or about 40.7 miles per day," James told us back in 2016. "Pretty amazing. So, I doubt he broke his journey for much more than the five hours you watched him--he could be 100 miles further south by now."
This year, to date, we have not seen a single Monarch in our pollinator garden. James estimates we will start seeing the first ones within the next few weeks. "Johnson has already had one of his tagged monarchs recovered, admittedly only a few miles away but it was heading south!"
Butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, spotted four within half an hour in the UC Davis Arboretum and Public Garden on Aug. 26. One was a tattered male. (See Bug Squad blog)
What to do if you see a WSU-tagged Monarch? Photograph it, if you can, and contact David James at firstname.lastname@example.org or the PNW Facebook page. Also, report any Monarch sightings to iNaturalist and Journey North.
Meanwhile, Monarch scientists, citizen scientists and Monarch enthusiasts are looking forward to the 2023 International Western Monarch Summit, set Friday through Sunday, Jan. 20-22 at Pismo Beach, San Luis Obispo. Registration is now underway. It's sponsored by Western Monarch Advocates (WMA), which relates its mission is "to serve as an overarching entity to encourage and facilitate communication and interaction of groups and individuals committed to restoring the western monarch butterfly population-regardless of their affiliation or location--in the hope that the shared knowledge will empower each of them to improve and better achieve restoration goals within their own respective affiliation or location."
The International Union for the Conservation of Nature (IUCN) placed the migratory monarch butterfly on its Red List of threatened species on July 21, 2022, classifying it as endangered.
"In the 1990s, nearly 700 million monarchs made the epic flight each fall from the northern plains of the U.S. and Canada to sites in the oyamel fir forests north of Mexico City, and more than one million monarchs overwintered in forested groves on the California Coast," according to the Xerces Society for Invertebrate Conservation. "Now, researchers and citizen scientists estimate that only a fraction of the population remains, monarchs have declined by more than 80% since the 1990s from central Mexico, and by more than 99% since the 1980s in coastal California."
It's early spring and Western monarchs are heading inland from their overwintering sites along the California coast.
Have you seen any monarchs?
A group of monarch researchers from Washington State University, Tufts University, University of California at Santa Cruz, and the Xerces Society for Invertebrate Conservation seek your participation in the Western Monarch Mystery Challenge to help gain insight as to where the monarchs go. They want to fill "a critical gap in knowledge about habitat needs of migrating monarchs in the spring."
“We are very excited to see so many western monarchs on the coast this winter!" said conservation biologist and lead researcher Cheryl Schultz, a professor in Washington State University's School of Biological Sciences, in noting that the 2021 Thanksgiving count directed by the Xerces Society of Invertebrate Conservation totaled 247,237, a 100-fold increase from the less than 2000 monarchs recorded in 2020. "Monarchs are resilient. Because the numbers are up this year, it is a fabulous opportunity to learn where they go when they leave the coast as they head to breeding areas."
The challenge, launched Feb. 14 and to end April 22 (Earth Day), is a call to action: If you see a monarch in the area of California, Oregon, Washington, Nevada, Idaho and Utah (see map below), what you do is report the sighting, take an image (a cell phone photo is fine) and enter it the campaign for a chance at a prize.
While on sabbatical at UC Davis, Crone presented a seminar Jan. 29, 2020 to the Department of Entomology and Nematology on "Why Are Monarchs Declining in the West?"
“Surprisingly, we don't really know where western monarch butterflies are during this time period, roughly mid-February through mid-May," Crone told the UC Davis crowd. "Future research will focus on filling this knowledge gap, as well as building quantitative knowledge of the western monarch demography throughout their complex annual life cycle, which is needed to understand the relative contributions of habitat at different points in the life cycle to population declines and recovery.”
Crone related that what fascinates her about monarchs is "the possibility that we can recover the western monarch population from its recent steep decline to being abundant again. This should be a problem we can fix."
The Western Monarch Mystery Challenge "is an opportunity to get even more people to participate in western monarch community science–and these animals need our help right now, more than ever," said conservation biologist Emma Pelton of the Xerces Society.
"We know they spend winter months (November to February) in groves along the California Coast, and start breeding in central California in May," the group of researchers wrote in an email. "However, we know little about where monarchs are in March and April. Solving the mystery of where western monarchs spend the spring is central to conserving and restoring the phenomenon of monarch migration in the West."
The call to action, they said, is simple:
- If you see a monarch outside the overwintering groves, take a picture (don't worry, it can be blurry). We suspect that monarchs spend the spring somewhere between the coast and the Central Valley
- Report it to iNaturalist (the app is free) OR email it to email@example.com and include species, date and location
- Be automatically entered to win a variety of prizes every week you report a sighting. Be sure to check your messages on iNaturalist if you use the app to submit sightings. If you upload a monarch photo from outside the overwintering sites (and not any from monarch rearing projects as these "skew the data and could jeopardize the quality and legitimacy of conservation plans) you will automatically be entered in a weekly prize drawing. Prizes include gift cards to REI and other awards. More information is available at https://labs.wsu.edu/conservation-biology/western-monarch-mystery-challenge/
The Western Monarch Mystery Challenge is supported by the Monarch Joint Venture in collaboration with the Western Association of Fish and Wildlife Agencies, as part of its Western Monarch Conservation Plan, 2019-2069, a regional program to restore and recover monarch butterflies across the Western landscape.