Our showy milkweed (Asclepias speciosa) is putting on a show.
The towering plant--a good eight feet--anchors the garden as we patiently wait for monarch butterflies to arrive and lay their eggs.
It's mid-August and it appears the monarchs are not coming here to our little pollinator garden in Vacaville, Calif. Maybe we'll see some during their late summer or early fall migration--on their way to their overwintering sites along coastal California.
Meanwhile, the speciosa has more than its share of lady beetles (aka ladybugs) and aphids.
But now we have a new visitor, well, maybe a permanent resident.
A praying mantis, Stagmomantis limbata (as confirmed by mantis expert Lohit Garikipati, a UC Davis graduate and Bohart Museum of Entomology associate now attending graduate school in Towson University, Maryland) has arrived.
For the first several days, Ms. Mantis hung upside down and did not eat (at least in our presence). She watched the bees buzzing around but made no effort to snag one. We think she was yawning. "Okay, I know you're there. I don't care and I'm not hungry."
Then we found her exoskeleton on one of the speciosa leaves.
A mantid's "skeleton," you know, is outside its body and it's known as an "exoskeleton." It reminds us of a suit of armor, for protection, support and form (is it a "suite of amour" when love abounds?).
A young mantis eats and outgrows its exoskeleton and then it molts (sheds it). Scientists say some species of growing mantids may lose their exoskeletons as many as 10 times.
And, according to Garikipati, a mantis that has just molted may not eat for two or three days.
Did you hear that, bees?
So, bottom line, no monarchs on the milkweed.
But we do have assorted lady beetles, aphids, and one praying mantis and her exoskeleton.
Wait, correct that. Just one mantis. A breeze just swept away the exoskeleton.
They're not, of course.
And neither are butterflies always "pretty." They can be "pretty gross," according to a delightful children's picture book, "Butterflies Are Pretty...Gross," by Rosemary Mosco with illustrations by Jacob Souva.
Yes, they can.
Mosco is a science writer and naturalist who tells it like it is, not how we want it to be. No sugar-coating. No candy-coating. No coats.
It's all there: "Warning — this book contains top-secret information about butterflies! Prepare to be shocked and grossed out by this hilarious and totally true picture book introduction to a fascinating insect."
Impersonating a "pretty" butterfly, Mosco relates that "We flutter through meadows, we pose on fancy flowers, we show off our wings, we shimmer with all the colors of the rainbow."
Then she cautions "Don't turn the page. Close the book. You're done. The story's over. Nothing to see here."
Oh, but there is!
Mosco goes on to tell us what butterflies land on, what they eat, what they slurp and other scientific facts. (We won't spoil the endings.)
It's a fantastic book--especially for those interested in science--as she covers the metamorphosis from egg to caterpillar to chrysalis to adult. Readers, both children and adults, will learn something new on each page.
Mosco mentions seven butterfly species, including the Monarch, Danaus plexippus; Harvester, Feniseca tarquinius; Alcon Blue, Phengaris alcon; Red Cracker, Hamadryas amphinome; Giant Swallowtail, Papilio cresphontes; Red-Banded Hair Streak, Calycopis cecrops; and Julia Heliconian, Dryas iulia.
Butterflies, she points out, taste with their feet, and a Monarch mama "tastes the leaves" before laying her eggs. Then she asks "What if your parents stuck their feet in your cereal before you ate it?"
Can't you just hear young readers or listeners yelling "Yecch"? (Remembrances of the UC Davis Bohart Museum of Entomology tours when the guides say "Don't say yecch! Say interesting!" And they do!)
Mosco's passion for insects shines through in this book. You may remember her as the co-author of the New York Times' bestseller, "The Atlas Obscura Explorer's Guide for the World's Most Adventurous Kid." The colorful illustrations are kid-friendly and as memorable as the text.
Yes, Rosemary Mosco does have a favorite butterfly. And it's not the Monarch. The author, who lives in New England, says it's the Guava Skimmer, Phocides polybius. Native to the Americas, this species was first described by Johan Christian Fabricius in 1793.
"It's a tropical butterfly," says butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology. "In the United States, it's recorded only as a stray from Mexico in the Rio Grande Valley, Texas."
"This species (Phocidespolybius) is nearly everyone's favorite," according to the North American Butterfly Association (NABA) of South Texas. "The adult often makes long stops at flowers allowing for excellent photographs to be taken."
(Editor's Note: For information on butterflies found in the Central Valley of California, access Professor Art Shapiro's research website. He has been studying butterfly populations in the valley since 1972.)
Don't tell the honey bees.
They will forage where they want to--whether it's on bee balm, a dandelion or that controversial tropical milkweed, Asclepias curassavica.
Just before we cut back the tropical milkweed for the season, the honey bees got their last hurrah--the last bit of nectar for the year.
Why cut back tropical milkweed? Scientific research shows that this plant disrupts the monarch migration patterns when it's planted outside its tropical range, and can lead to the spreading of OE, orophryocystiselektroscirrha, a protozoan parasite that infects monarch and queen butterflies. So we gardeners cut it back AFTER the monarchs have quit laying their eggs for the summer (or early fall) and BEFORE the monarch migratory season.
Honey bees, however, do love that milkweed. (Note that some scientists, conservation organizations and horticulturists urge folks NOT to plant the non-native tropical milkweed, and if they do, cut it back before the migratory season. See post from Xerces Society of Invertebrate Conservation.)
Connie Krochmal's article on "Milkweed as Honey Plants" in the Aug. 23, 2016 edition of Bee Culture magazine points out just how much bees love milkweed.
"Very fond of milkweed blossoms, bees will desert other flowers when these are available. The plants provide a good nectar flow. Bees discard the pollen. Assuming enough plants are available, milkweeds can bring a good crop of honey."
Milkweed, Krochmal writes, "are major bee plants in the North Central states, the Northeast, Southeast, the Plains, and the mountainous West." The honey is typically light colored and mild-flavored, she added.
"Generally, milkweeds are considered beneficial to bees. However, there are potential negative aspects to milkweed flowers. It is conceivably possible for bees and other small pollinators to become trapped in a blossom. Also, the sticky pollen masses might cling to a bee's head or legs, thereby affecting her mobility or appearance."
Yes, it does. We've seen many a bee struggle to free herself from the pollinia. Some lose their legs. Some perish.
But that nectar--that nectar--the bees keep coming back for more.
Monarchs lay their eggs on the underside of milkweed leaves--generally--but we've seen them on stems and on the leaf edges. They usually deposit a single egg beneath the leaf, but we've spotted as many as four on one leaf. They secrete a glue so the egg will adhere.
Color? They're a creamy yellow with narrow longitudinal ridges from the top to the bottom. Size? About 0.9 to 1.2 mm long, or about the size of a pinhead.
They hatch about 3 to 4 days after they're laid. Then you'll see the black-headed tiny larva or caterpillar eating its shell before it begins devouring the leaf.
Some folks confuse the sap-sucking yellow oleander aphids with the monarch eggs. Or the yellow eggs of the lady beetle, aka ladybug. So we took a few images of them.
In our family pollinator garden in Vacaville, we've collected about 250 monarch eggs or caterpillars this year, and the mamas are still laying eggs! We're not the only ones who like monarchs. We try to collect the eggs before the predators and parasitoids get them. Predators include lady beetles (ladybugs), spiders, milkweed bugs, lacewings, and wasps. Tachinid flies and other parasitoids lay their eggs in or on the immature monarchs or deposit their eggs on a leaf that the caterpillar eats. The fly larvae develop inside the living host, killing it. Note: tachinid flies are considered beneficial insects when they lay their eggs in such pests as cabbageworms.
We grow five species of milkweed:
- Tropical: Asclepias curassavica
- Narrowleaf: Asclepias fascicularis
- Showy: Asclepias speciosa
- Butterfly weed: Asclepias tuberosa
- Swamp milkweed: Asclepias incarnata
But back to the question: how can you tell the difference between an oleander aphid and a monarch egg? They are so tiny and both are yellow! Basically, the aphid has legs and it moves! Some aphids are winged and fly. Another clue: aphids cluster together; you won't find monarch eggs in a cluster.
Note that the lady beetle lays her eggs in clusters, so if you find a cluster of eggs, those aren't monarch eggs.
Professor Elizabeth Crone of Tufts University who researches monarchs (as well as bumble bees), drew a standing-room only crowd when she presented a UC Davis Department of Entomology and Nematology seminar on the decline of Western monarchs.
UC Davis professor Neal Williams, a pollination ecologist who researches native bees, praised her "fearless perspective in the use of statistics; I value her insights." Williams has collaborated with her "off and on" for 20 years.
Crone, who just finished a six-month research sabbatical at UC Davis, says her work centers 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."
In her UC Davis seminar, Crone pointed out that the population of Western monarchs, which overwinter along the California coast, dropped from an estimated 4.5 million in the 1980s to less than 30,000 in the winter of 2019.
After the monarchs leave their overwintering sites in February and head inland, "we don't really know where they are in spring," Crone lamented. "There's not a lot of records of where monarchs are in spring. That's why we're trying to draw on citizen scientists to help us find monarch butterflies in the spring."
Crone is a member of a team of researchers, led by Cheryl Schultz, biology professor at Washington State University, who are recruiting the public, aka citizen scientists, to report sightings of monarchs from Feb. 14 through April 22, Earth Day. The project is called the Western Monarch Mystery Challenge.
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.
Crone told the UC Davis crowd that "we need to understand the basic biology throughout the life cycle....So from a conservation perspective, we know that we need to protect and restore overwintering sites on the coast of California...It also helps to improve summer habitat both for its own sake and maybe to mitigate losses. It other places, this includes planting your own pollinator gardens. It includes minimizing ;pesticide use society-wide."
It's not just agriculturists who use pesticides, said Crone, noting that "California tracks pesticide use." She showed a database that indicated 25 percent of the state's total pesticide use is for non-agricultural uses. This includes pesticide applications in parks, roadsides and golf courses, she said. "That doesn't include people who go to Lowe's or Home Depot and pick up a can of insecticide to prevent the aphids from eating their roses. And read the label and it says, 'Why don't you just spray every week so you never see aphids at all?' So we should be very aware that pesticides are everywhere in our landscape, and a lot of us are using them without thinking about them. And anything we can do to minimize pesticides has got to be good for nearly all insects."
From an applied ecology perspective, Crone considers her biggest accomplishment "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."
"It's an exciting time to be an ecologist," Crone said. "Because the puzzle of linking natural history and theoretical ecology to guide conservation is really intellectually interesting, even from an academic perspective. And it also makes me optimistic."
"We did it with Fender's blue butterfly," she told the crowd. "Maybe we can help prevent other insect populations from being at risk of extinction."
To listen to her talk, access this newly uploaded video from ucdavis.edu/media. Access is free.