Unless it encounters a predator or parasitoid or another life-threatening factor, the egg will usually hatch 3 to 4 days after Mama Monarch deposits it beneath a milkweed leaf. As you know, monarchs lay their eggs only on milkweed, their host plant.
If you enjoy macro photography, it's a delight to photograph an egg with a highly specialized lens like the Canon MPE-65mm lens. Or you can observe the tiny egg with a magnifying glass or microscope.
How do you rear it?
Naturalist Greg Kareofelas, an associate of the Bohart Museum of Entomology at the University of California, does it this way:
"I put a single egg on its leaf in a small salsa container (the little plastic ones you would get at a Mexican restaurant). I take a square of toilet paper and fold it into a small square (3/4 of inch), dampen it and squeeze it so it is not sopping wet, just damp, and set the leaf and egg on the top. Put the lid tightly on the container. This keeps a level of moisture in the container. I check the containers daily, changing the toilet paper square to keep from molding."
"I raise the larva in that container until it gets big enough to move to a larger container. As long as you pay attention and check them often to make sure there is no mold or such, I have raised many this way successfully. The tight lid and slight moisture keeps the food plant fresher."
"You don't want loose water in the container, just enough so it is not dry," he says.
Among the many species of butterflies he's reared: the dogface butterfly or California state insect, Zerene eurydice; the Colias behrii, the Behr's sulphur or Sierra green sulfur; and the monarch, Danaus plexippus.
When our family rears monarchs, we usually begin with the caterpillars instead of the eggs. They're easier to find and collect. However, if you see a monarch laying her eggs, you know exactly where to look! Last weekend we watched a monarch deposit her eggs on our tropical milkweed, Asclepias curassavica, and our narrow-leaf milkweed, Asclepias fascicularis. We collected three eggs from the fascicularis and let the others be.
An adult monarch can lay about 400 eggs in her lifetime, Kareofelas says. Only a few survive due to predators and parasitoids and other factors. The major parasitoid in our garden is the tachinid fly which lays its eggs in or on the host or deposits its eggs on the milkweed leaves.
"If you start with the egg, the chance of it being parasitized is really small," says Kareofelas, who has been rearing butterflies most of his life, and especially for the last 15 years.
When the egg hatches into a larva or caterpillar, the 'cat will eat the eggshell first and then go about munching the milkweed. When it gets bigger, it's time to move it into a larger container. You must keep the milkweed fresh, as it can dry out quickly. Kareofelas likes to use water-filled floral tubes and dampened packing foam to keep the leaves/stems moist.
Our family's procedure to rear caterpillars: fill a heavy, wide-bottomed, narrow-necked tequila bottle with water, add sprigs of milkweed and the 'cats, and place in a zippered, net butterfly habitat. We place ours in our kitchen, a tachnid-free environment! Those tachnids can be sneaky! Also, replenish your milkweed and water daily, and remove the frass (excreta) daily.
It's a joy watching the complete metamorphosis, about a 30-day development from egg to larva to chrysalis to adult. The larval stage or caterpillar stage usually lasts 10 to 14 days, during which time the caterpillar will go through five instars (when it molts or sheds it skin). The 'cat will then form a "j" and pupate. The chrysalis stage lasts about 10 to 14 days, and voila! The familiar monarch icon ecloses and it's released back into the garden to start the cycle all over again.
Yes, it's a joy to watch them. But it's not a joy watching a tachnid-infested monarch caterpillar or a chrysalis. (We'd rather the tachnids lay their eggs in such pests as cabbage loopers or tomato hornworms.)
A good place to see butterfly specimens from all over the world is the Bohart Museum of Entomology (now temporarily closed due to the COVID-19 pandemic. Of the nearly eight million specimens in the Bohart, some 500,000 are in the Lepidoptera collection, curated by entomologist Jeff Smith. He and Kareofelas display and discuss the Lepidopterans during the open houses. In the meantime, watch the moth-butterfly videos on the Bohart Museum page.)
Which one is the most popular? Initially, it was the tropical milkweed, A. curassavica. We collected the first five caterpillars there. The A. fascicularis yielded the rest.
So, the count: narrowleaf milkweed, 11; tropical, 5; and showy, a no-show.
To date this year, we have released six monarchs back into the garden. The others went for university research. Elizabeth Pringle's laboratory at the University of Nevada, Reno, needed male and female monarchs to rear a colony, and the UC Davis laboratory of Louie Yang needed some tachinid flies.
Unfortunately for us--and fortunately for the Yang lab--tachinid flies infested two of our "11-piece collection." The adult flies are parasitoids that lay their eggs in immature monarchs (among other hosts). The fly larvae hatch and eat their host from the inside out. In a chrysalid, you can tell a tachnid fly infestation by the large tell-tale "dented" brown spot, it looks somewhat like a rotten spot on an apple. In a caterpillar? Think withered and discolored. Then a bungee-like white string appears, and the larvae (maggots) slide down--probably gleefully--like a kid on a Goliath Slide at the county fair.
Tachinids, however, are considered beneficial insects. They lay their eggs in or on such pests as cabbage loopers, cutworms, cabbage worms, gypsy moths, hornworms, harlequin bugs, lygus bugs, cucumber beetles, earwigs and the like. (See Bug Squad blog for close-up images of the tachinid larvae and pupae.)
2016: A Very Good Monarch Year
The year 2016 was a very good year for monarchs in our pollinator garden; we reared and released 60-plus. Sadly, the numbers fell drastically in 2017, 2018 and 2019. Last year, no eggs, no caterpillars and no chrysalids, and only a few monarchs passed through. In fact, in 2019 we did not see our first monarch until Aug. 9.
This year we're noticing a comeback of sorts. We spotted the first monarch on May 24. We now see:
- Males patrolling our yard and chasing the females--morning, noon and evening
- Females laying their eggs on the narrowleaf milkweed that's beneath the honeysuckle vine or the tropical milkweed that's beneath the roses
- Both males and females nectaring on milkweed, butterfly bush (Buddleia davidii), and Mexican sunflower (Tithonia rotundifolia), napping in the branches of the cherry laurels, and greeting any guests with flutter fanfare.
Life is good.
Sometimes the Gulf Fritillaries, Agraulis vanillae, that are hanging out on their host plant, the passionflower vine, mistake them for one of their own species and a pursuit begins.
Yes, the predators are out there: the California scrub jays, praying mantids, spiders, European paper wasps and yellow jackets. So are the tachinid flies and parasitoid wasps.
Would it be too much to ask them to...um....leave our monarchs alone? Yes.
Everybody eats in the garden. The menu choice is theirs.
Meanwhile, scientists want to know where the monarchs are in the early spring. When the iconic butterflies head inland from their coastal overwintering sites, where do they go?
To participate in the Western Monarch Mystery Challenge:
- If you see a monarch outside of overwintering groves, take a picture! (Don't worry, it can be far away and blurry.)
- Report it to iNaturalist (the app is free) OR email MonarchMystery@wsu.edu and be sure to include date, species and location for both methods
- You will automatically be entered to win a variety of prizes every week you report a sighting.
All data will be added to the Western Monarch Milkweed Mapper, a year-round community science project tracking milkweeds and monarchs in the West.
UC Davis alumnus Christopher Jason, a technician in the Schultz lab, said WSU researchers are collaborating with the Elizabeth Crone lab at Tufts University; Xerces Society of Invertebrate Conservation; and UC Santa Cruz. Crone, a biology professor recently on a research sabbatical at UC Davis, told the UC Davis Department of Entomology and Nematology at a seminar Jan. 30 (the same day that Shapiro sighted a monarch in Sacramento) that more research needs to be done on where monarchs are in the spring, as that is a "critical point in their life cycle." Monarch populations are at their lowest at this time of year, Crone said, and individual butterflies may be at their "weakest right after their long overwintering diapause.”In an email, Jason reiterated that "The Western Monarch Mystery Challenge is a campaign to find out where western monarch butterflies are in early spring. We know they spend the winter months (November to February) in groves along the California coast, and start breeding in central California in May, and in some cases, as early as February. However, we know a lot less about where they are and what they're up to in February, 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 Xerces Society for Invertebrate Conservation reported this week that its Western Monarch Thanksgiving Count shows a decline for the second consecutive year. “Sadly, fewer than 30,000 monarchs were counted—29,418 to be exact—for the second year in a row, so the western monarch population remains at a critical level,” according to Matthew Shepherd, director of communications and outreach. (See Xerces press release and blog about the population count for this winter.)
Researcher Elizabeth Crone, a professor at Tufts University, Medford, Ma., will shed some light on the issue when she delivers a UC Davis Department of Entomology and Nematology seminar on "Why Are the Monarch Butterflies Declining in the West?" from 4:10 to 5 p.m., Wednesday, Jan. 29 in 122 Briggs Hall, off Kleiber Hall Drive, UC Davis campus. Her longtime collaborator, pollination ecologist and professor Neal Williams, will introduce her.
"Ecologists now face the dual challenge of documenting changes in the environment, and figuring out appropriate strategies for conserving and recovering natural resources in changing environments," says Crone, who is completing a research sabbatical at UC Davis. In her talk, she will focus on “using the tools of population ecology to address both sides of this challenge: quantifying changes in the abundance of western monarch butterflies (and factors associated with these changes), and using theory and data to design strategies and targets for restoration and recovery.”
“Analyses of past dynamics (1980-2017) showed that western monarch butterflies have declined more quickly than their eastern counterparts, and that these declines were most strongly associated with loss of overwintering habitat, and more weakly (but significantly) associated with increased pesticide use and warmer breeding season temperatures,” Crone writes in her abstract. “Analyses of current conditions (2018-2019) suggest that a recent dramatic drop in abundance occurred in spring, between when monarch butterflies leave coastal overwintering sites and arrive in the Central Valley and Sierra Foothills.”
The Xerces Society for Invertebrate Conservation reported this week that its Western Monarch Thanksgiving Count shows a decline for the second consecutive year. “Sadly, fewer than 30,000 monarchs were counted—29,418 to be exact—for the second year in a row, so the western monarch population remains at a critical level,” according to Matthew Shepherd, director of communications and outreach. (See press release and a blog article about the population count for this winter.)
A native of Alexandria, Va., Crone received her bachelor's degree in biology, summa cum laude, from the College of William and Mary, Williamsburg, Va., in 1991, and her doctorate in botany from Duke University in 1995. She served as a postdoctoral researcher at the University of Washington, Seattle, from 1996-1997. Her career encompasses academic appointments at Harvard University, University of Montana, and the University of Calgary.
No stranger to UC Davis, Crone has collaborated with Neal Williams "on and off" for the past 20 years. “We had a National Science Foundation grant to study bumble bee populations from 2014-2019, so I have been visiting regularly since he got here. Starting in winter 2019, I have also had funding to take partial research leave from Tufts and work on western monarchs. I have been about half-time at Tufts and half-time at UC Davis." "I am grateful to Neal and the Entomology Department for hosting me during this extended stay!" she added.
Crone is a co-principal investigator (PI) with PI Cheryl Schultz, associate professor of biological sciences at Washington State University and co-PI Sarina Jepson, endangered species program director, Xerces Society, on a federal grant, "Western Monarch Breeding Phenology" (awarded May 2017-June 2020, with the potential for annual renewal). The grant was funded through the Department of Defense's (DoD) Natural Resources Program, DoD Legacy Program.
Of her research, Crone says "My research focuses on population ecology, especially of plants and insects, and plant-animal interactions. Specifically, I am interested in how environmental changes translate to changes in population dynamics: For example, is there a simple, linear matching of changes in resources to abundance of consumers, or do interactions among individuals and species moderate these responses? Much of my research also involves developing novel quantitative approaches to predict long-term dynamics from small scale observations and experiments. Current projects include studies of butterflies, bees, perennial wildflowers, sugar maples, and acorn-granivore interactions. Past projects include some of the best documented examples of cyclical dynamics in plant populations and spatial metapopulation dynamics in animal populations. I was also one of the first ecologists to adapt generalized linear mixed models to estimate variance terms for stochastic population models."
Her honors and awards are many and varied:
- Project of the Year Award, SERDP (Strategic Environmental Research and Development Program) 2018
- Foreign Member, Finnish Academy of Science and Letters (elected 2017)
- Vice Chair / Chair, Theoretical Ecology Section, Ecological Society of America, 2010-2012
- Ecological Research Award, Ecological Society of Japan, 2014
- Fulbright Fellowship, 2007-2008
- National Science Foundation (NSF) Postdoctoral Fellowship in Biosciences Related to the Environment (1996-1997)
- U.S. Department of Energy Graduate Fellowship for Global Change (1991-1995)
- Baldwin Speece Award (College of William and Mary, for scholarship/service in ecology, 1991)
How did you get interested in science? Was there an "ah ha" moment?
I was in an REU (Research Experiences for Undergraduates) program studying plant-insect interactions in 1990. The thing that made me want to go to grad school was the fun puzzle of designing an experiment AND figuring out how to interpret the data - I had collected data on beetle feeding rates, and when I didn't know how to analyze them my advisor said "read a statistics book" ... so I did--since then I have always especially loved the puzzle of matching models to data.
From an earlier age, I have always enjoyed being outdoors, which is probably why I chose to study biology. But that was the moment when I knew I would enjoy a life of research.
Some of your major accomplishments?
From an applied ecology perspective, the biggest is helping the Fender's blue butterfly move from being listed as endangered to nearly ready for down-listing. From a basic ecology perspective, I figured out the ecological interpretation of variance terms in mixed models as estimates of spatial heterogeneity and environmental stochasticity, and worked out one of the best examples of how mast-seeding species are synchronized by their pollinators.
What fascinates you about monarchs?
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.
What do you like best about science?
The puzzle of matching models to data and the possibility of saving species from extinction.
Any scientists in the family?
My sister is an astronomer. My dad was a math professor. Before him, though, no one in the extended family had even gone to college.
What do you do in your leisure time?
I once gut-renovated a house (with help from carpenters, but doing some of the work myself), I am very proud of my urban pollinator garden in Somerville (near Boston, Mass., and I am a good enough trombonist to (just barely) keep up with my trombonist friends.
I am waiting to find out whether our monarch funding will be extended or whether I will go back to a regular teaching schedule at Tufts. Even if I go back to "full-time" teaching, I am sure I will be doing western monarch and bumble bee research for the indefinite future, and will continue to be at least partly bicoastal.
(Editor's Note: the Xerces Society's site-by-site monarch count data is available at https://www.westernmonarchcount.org/data/. This covers all years since the first count in 1997.)
Scientists, conservationists and citizen scientists were there to discuss "Recovering the Western Monarch Butterfly Population: Identifying Opportunities for Scaling Monarch Habitat in California's Central Valley."
"The western population of the monarch butterfly has garnered widespread attention because of its dramatic decline in recent decades," the Environmental Defense Fund said in its opening statements. "The latest population surveys indicate that monarchs overwintering on the central coast have declined 86% since last winter and now total 0.5% of their historical average. Population declines have spurred greater scientific study, funding, and coordination around the western monarch. California legislators appropriated $3 million in funding to the California Wildlife Conservation Board to establish the Monarch Butterfly and Pollinator Rescue Program."
In his presentation, Shapiro told the group: "As of right now, the monarch is on life support in California, and we are reduced to prescribing placebos. If our patient comes back from the brink—as history suggests it may well—will we convince ourselves that our placebos worked? Probably. And that's not how to do science. That's what philosophers call the fallacy of post hoc, ergo propter hoc." (See Shapiro's other comments)
Shapiro, who has monitored the butterfly populations of central California for more than four decades, posts his research on his website, Art's Butterfly World.
Meanwhile, the widespread interest in monarchs continues to widen. What's happening with the monarchs this year?
If you're a University of California Master Gardener and want an update on the status of Western monarchs, be sure to attend Shapiro's presentation at the UC Master Gardeners' Fall Conference on Saturday, Oct. 26 in the Veterans Memorial Senior Center, 1455 Madison Ave., Redwood City.
The event, to take place from 9:30 a.m. to 3 p.m., includes a talk by Shapiro from 1:15 to 2:45 p.m. on "The Controversy on the Western Monarch Monarch Butterfly."
- 9:30-9:45: Welcome and Introductions, Shirley Melnicoe, president and Kali Burke, new program coordinator
- 9:35-10: Recognition, Ginny Piazza, membership chair
- 10 to 11: Soils Group presentation by Master Gardeners Joe Lees and Nick Landolfi
- 11 to 11:15: Break
- 11:15 to 11:45: Igor Lacan, UC Cooperative Extension Advisor for San Francisco Bay Area, The Odonata Order – The Mystery of Dragonflies
- 11:45 to noon: Sheena Sidhu, staff biologist, San Mateo County Department of Agriculture on Pests and Diseases, Latest Pests & Diseases in San Mateo County
- 12 to 1: Lunch
- 1 to 1:15: Master Gardeners leading some exercises, to be announced
- 1:15 to 2:45: Arthur M. Shapiro, UC Davis distinguished professor of evolution and ecology, The Controversy on the Western Monarch Butterfly
- 2:45-3: Closing comments/wrap-up