A monarch butterfly fluttered into our pollinator garden in Vacaville yesterday and sipped nectar from a Mexican sunflower (Tithonia) as a bird looked on.
Well, sort of looked on.
The bird was decorative art. The monarch was real.
Now if that bird had been real, the monarch may have been a meal.
It would not have tasted very good, though, due to the infamous cardenolide defense, which the monarch gets in its caterpillar stage while chowing down milkweed, its host plant.
Yes, birds eat monarch butterflies, but they don't eat them like people eat potato chips.
We remember the Linda Fink-Lincoln Brower research article published in May 1981 in the journal Nature about how some birds can overcome the cardenolide defense of monarch butterflies in Mexico.
"Flocks of black-backed orioles (Icterus abeillei Lesson) and black-headed grosbeaks (Pheucticus melanocephalus Swainson) eat several hundred thousand monarch butterflies (Danaus plexippus L.) in the dense overwintering colonies in central Mexico, and in 1979 were responsible for over 60% of the butterfly mortality at several sites. Such predation is unusual because, during larval development the aposematically coloured monarch butterfly sequesters cardenolides from its milkweed foodplants (Asclepiadaceae). These bitter-tasting heart poisons cause vomiting in 12 species of birds in 9 families, although the domestic chicken, Japanese quail, hedgehog, mouse and sheep have been shown to be insensitive to their emetic effects. Extensive predation of monarch butterflies by birds has never been observed except in Mexico. We report here that the Mexican butterflies are weakly emetic, and that taste discrimination by orioles and cardenolide insensitivity of grosbeaks allow these birds to feed freely on monarch butterflies."
We've seen birds scatter the overwintering monarchs roosting in the eucalyptus trees at Pacific Grove, Santa Cruz, but never witnessed an all-you-can-eat buffet. They ate a few, though.
Where are all the monarch butterflies?
There's good news and bad news.
First, the bad news:
"An Epic Migration on the Verge of Collapse," wrote the Xerces Society for Invertebrate Conservation on its website detailing monarch conservation.
"Both the eastern and western migrations have experienced significant decline in a matter of decades," they wrote. "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. Now, researchers and citizen scientists estimate that there has been a decline of more than 80% in the east. In the west, the news is more dire. Monarchs have experienced a decline of 99.4% in coastal California, from an estimated 4.5 million in the 1980s to 28,429 as of January 2019."
In our pollinator garden in Vacaville, I've seen only two monarchs this year. One, a female, lingered on the Mexican sunflowers (Tithonia rotundifolia) and butterfly bush (Buddleia davidii) for about 30 minutes on Sunday.
But as luck would have it, a family member spotted a monarch this morning in the garden section of a home improvement store in Vacaville and captured this video (below). It was laying eggs on tropical milkweeds, Asclepias curassavica.
That's three. That's a far cry from the 60 we reared in 2016.
Now the good news:
Brookings, Ore., is fluttering with monarchs.
From the Facebook page, Monarch Butterflies in the Pacific Northwest, covering Washington State University entomologist David James' research and the work of his many citizen scientists, comes the remarkable story of a female monarch named Ovaltine (since passed) and her progeny:
Aug. 23: "The biggest Monarch story on the west coast right now has to be the population explosion in the far southern Oregon coastal town of Brookings! From a single female (that we know about) 'dumping' more than 700 eggs at one Monarch Waystation in late June, there is now such an abundance of Monarchs in Brookings that every patch of Milkweed seems to have eggs on it! It's quite likely that a few other Monarchs also laid a lot of eggs in Brookings in June, but what has been surprising is the way that females have targeted single Milkweed patches for egg 'dumping'. Egg 'dumping' has been observed in other Brookings Milkweed patches, some of them very small. Holly Beyer, whose Waystation hosted the first egg 'dumping' female, has now had to limit egglaying by the new generation of 'egg dumpers' by enclosing her milkweed in netting cages, for fear of the larvae running out of food! I have never heard of anybody needing to do this before! Brookings is an official 'Monarch City' so its certainly living up to its name and the Monarch festival to be held there in early September should be graced by plenty of Monarchs dropping in!"
Aug. 29: "Holly has counted more than 1800 eggs laid by Ovaltine's tagged daughters in her garden! Ovaltine's 'grandchildren' will soon begin eclosing (from mid-September to mid-October) and of course will be the migratory generation. Their numbers will be limited by milkweed availability in Brookings but I expect significant numbers of fresh, migrant monarchs to be milling around Brookings in the coming weeks, feeding on nectar before they depart southward. If Holly had not captive-reared Ovaltine's progeny, there would not be monarchs flying around Brookings in the numbers we are currently seeing! We do not generally consider captive-rearing to be a good conservation strategy for monarchs but in this instance it has demonstrably contributed to monarch conservation. If you want to see monarchs flying, then a trip to Brookings, Oregon in September could be in order!"
If you see any WSU-tagged monarchs migrating through California to their overwintering sites along the coast, photograph them and contact David James at firstname.lastname@example.org. We distinctly remember the tagged monarch from Ashland, Ore. (tagged by Steve Johnson and part of the David James' citizen science project) that passed through our garden on Labor Day, 2016. (See Bug Squad post.)
Today is Labor Day 2019, a federal holiday celebrated the first Monday of September.
However, "the girls" are working, as they do every day of the year, weather permitting.
"The girls" are the worker honey bees.
Unless you keep bees or have access to a hive, you mostly see them foraging. But inside the hive, they are also nurse maids, nannies, royal attendants, builders, architects, dancers, honey tenders, pollen packers, propolis or "glue" specialists, air conditioning and heating technicians, guards, and undertakers.
They ensure the survival of the hive, but their life span is short.
"Worker bees live for approximately five to six weeks in the spring and summer," writes author and retired bee scientist and bee wrangler Norman Gary, emeritus professor of entomology at the University of California, Davis, in his book, Honey Bee Hobbyist: The Care and Keeping of Bees."Those reared in the fall live for several months--long enough for the colony to survive the winter--and are replaced by young bees in late winter or early spring."
In peak season, a honey bee queen can lay 1500 to 2000 eggs a day, and most of them will be worker bees, the most needed of the three castes (queen, drone and worker) in the hive. Although the smallest, but they do most of the work. The queen is the egg layer. The drone's role is strictly reproduction.
Worker bees forage within four to five miles of their hive. If you provide no nectar or pollen sources in your yard, they'll go elsewhere.
Theirs is a dangerous occupation. No thanks to predators (such as birds, praying mantids and spiders) and pesticides, many do not return home at night.
Like to photograph them? Try the "magic hour," which occurs about an hour before the sun sets. We love photographing them on Mexican sunflowers (Tithonia). The light is soft, warm and welcoming.
(Editor's Note: Interested in becoming a beekeeper or learning more about beekeeping? Be sure to check out the UC Davis-based California Master Beekeeper Program, directed by Extension apiculturist Elina Lastro Niño of the UC Davis Department of Entomology and Nematology. The next course is on managing varroa mites, a major pest.)
A pollinator garden is a study in diversity--and of inclusion and exclusion.
The residents, the immigrants, the fly-bys, the crawlers, the wigglers, the jumpers. The big, bad and bugly. The prey and the predators. The vegetarians and carnivores.
The nectar-rich flowers attract honey bees, bumble bees and butterflies. And right near them are the predators: the praying mantids, dragonflies and assassin bugs.
The assassin bugs, family Reduviidae, are ambush predators. They resemble human assassins (or at least those on the movie screen!): long narrow neck, beady eyes, and sturdy body. When they ambush a predator, they stab it with their rostrum, inject venom, and suck out the juices. Or as UC Berkeley entomologists Jerry Powell and Charles Hogue write in their book, California Insects, "The victims, which include all kinds of insects, are snatched by quick movements of the forelegs, and immediately subdued by a powerful venom injected through the beak."
Such was the case with the assassin bug, Zelus renardii, this week. We watched one lie in wait on a Mexican sunflower (Tithonia); we watched another dine on an unidentifiable prey on a milkweed blossom; and we watched yet another stab a lady beetle (aka lady bug) on a leaf.
Everybody eats in the pollinator garden.
We never thought we'd see one this year.
And then it arrived.
The first monarch sighting of the year.
A Danaus plexippus majestically touched down on our Mexican sunflowers (Tithonia) around 5 this afternoon in our pollinator garden in Vacaville, circled the milkweed plants about 10 times, and then fluttered over the roof and vanished.
Meanwhile, we managed to grab a couple of photos of the iconic butterfly.
Fellow monarch enthusiasts report the scarcity of monarchs.
"Haven't see any this year," said one.
"Me, either," said another.
"No, not a single one," said yet another. "I'm looking."
Rita LeRoy has seen two at the Loma Vista Farm, Vallejo.
"Send some over to us," we said.
We remember butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, commenting at a meeting hosted at UC Davis Feb. 28, 2019 by the Environmental Defense Fund, that "monarchs are on life support." The attendees--some scientists, some citizen scientists--were there to discuss "Recovering the Western Monarch Butterfly Population: Identifying Opportunities for Scaling Monarch Habitat in California's Central Valley."
The organizers related that "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 CA Wildlife Conservation Board to establish the Monarch Butterfly and Pollinator Rescue Program."
"Additionally," they said, "the Western Association of Fish and Wildlife Agencies released a Western Monarch Butterfly Conservation Plan calling for an additional 50,000 acres of monarch-friendly habitat in the California Central Valley and adjacent foothills by 2029. Join Environmental Defense Fund along with farmers, restoration practitioners, and scientists for an invitation-only workshop to share expert knowledge and identify strategic opportunities for restoring monarch butterfly habitat across the Central Valley. We will discuss important topics including opportunities for monarch habitat in the food production landscape, incentivizing monarch habitat restoration using limited resources, production and distribution of native plants, and other subjects that will put the western monarch butterfly population on the path to recovery. We will use the results of the workshop to inform conservation initiatives and effectively and efficiently allocate funds and resources for optimal conservation outcomes."
Shapiro was one of the five speakers in the "State of the Science" workshop section. He has been monitoring Central Valley's butterfly population since 1972 and maintains a website on his research.
In his presentation, Shapiro declared that "monarchs are on life support in California, and we are reduced to prescribing placebos."
"Consider a doctor faced with a patient in rapid decline," Shapiro told the group. "All tests have failed to identify the cause. What is the doctor to do? You can't prescribe treatment for an undiagnosed illness, can you? You can make a wild stab at a prescription on the basis that the patient is going to die anyway, and MAYBE, just maybe, this drug will do some good. Or you can prescribe a placebo, just to reassure the patient that you are doing something. That's where things get interesting. Occasionally a patient improves drastically on a placebo. Maybe he would have improved anyway; there's no way of knowing. Suppose our patient has a complete remission despite having received only a placebo. Does our doctor convince himself the placebo cured him? 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. We can do can do better than that!" (Read his presentation on a Bug Squad blog.)
Meanwhile, we know there's at least one monarch in Vacaville...Maybe it's a female and will return to lay eggs on our milkweed. We can only hope.