Oh, the joy of rearing monarchs...from an egg to a caterpillar to a chrysalis to an adult...
However, the ultimate joy is not in rearing them, but releasing them--from their confined and well-protected indoor habitat to that Spectacular Spacious World Without Boundaries. Some soar majestically 80 feet into the air, never looking back. Some decline to leave your hand and just cling there on your finger. And some leave your hands only to hang around the yard for five hours. Hey, do I have to go? Can't I just stay awhile?
It's been said that in Nature, 97 percent of monarch eggs don't reach adulthood. Or, to put it another way, the survival rate is 3 percent. Conservation, even on a mini-scale (we've reared and released 22 this year) is what it's all about.
Another joy is this: documenting them as they fly off or nectar on nearby flowers. Monarchs may live from minutes to hours to several weeks, depending on predators, diseases, deformities, food supply and migratory mishaps. Some live several months as they overwinter along coastal California and in Central Mexico.
Speaking of life span, we were rather surprised that a video of a monarch being released--and then eaten by a diving bird--emerged as one of three $100,000 America's Funniest Videos. Funniest? Not funny. True, that's what birds do, and do well, but the humor escapes many of us. It was more of an "Oh, No!" moment.
On a more pleasant note, it's good to see an increasing number of citizen scientists planting milkweed. They know that milkweed is the host plant of monarchs; that monarchs will lay their eggs only on milkweed; and caterpillars will eat only milkweed. No milkweed. No monarchs.
For more information on monarchs (Danaus plexippus) and planting milkweed, check out the wealth of information on the Xerces Society's monarch website. And read the news release by the Xerces Society's Emma Pelton on the 74 percent decline in the monarch in the number of monarch butterflies overwintering in coastal California.
How times change with the advancement of knowledge.
It's long been known that when honey bees—as well as other insects—get trapped in the milkweed's pollinia, or sticky mass of pollen, many perish when they are unable to free themselves.
So when we were perusing the book, ABC of Bee Culture, published in 1890 and written by noted beekeeping innovator/entrepreneur A. I. Root (1839-1923) of Ohio--with information “gleaned from the experience of thousands of beekeepers from all over the land”--we came across a surprising recommendation.
The surprising recommendation: If you want to kill off bees where they are not wanted, plant milkweed. In one reference, milkweed is described as a “useless weed.” (Actually, it's the only larval host of the monarch butterfly and without milkweed, no monarchs.)
Excerpt from ABC of Bee Culture:
"Milkweed (Asclepias cornuti). This plant is celebrated, not for the honey it produces, although it doubtless furnishes a good supply, but for its queer, winged masses of pollen, which attach themselves to the bees's feet and cause him to become a cripple, if not to lose his life. Every fall, we have many inquiries from new subscribers in regard to this queer phenomenon. Some think it is a parasite, others a protuberance growing on the bee's foot, and others, a winged insect enemy of the bee.” (Note that foragers are referred to as male, but all foragers are female.)
“It is the same that Prof. Riley alluded to when he recommended that the milkweed be planted to kill off the bees when they become troublesome to the fruit grower. The folly of such advice—think of the labor and expense of starting a plantation of useless weeds just to entrap honey bees---becomes more apparent when we learn that it is perhaps only the old and enfeebled bees that are unable to free themselves from those appendages, and hence the milkweed can scarcely be called an enemy. The appendage, it will be observed, looks like a pair of wings, and they attach themselves to the bee by a glutinous matter which quickly hardens so it is quite difficult to remove, if not done when it is first attached.”
There's a wealth of information in the encyclopedic ABC of Bee Culture, even the 126-year-old edition, but planting milkweed to kill bees and describing milkweed a "useless weed" aren't two of them.
How times change with the advancement of knowledge.
(Editor's Note: The newest edition of the ABC of Bee Culture is The ABC and Xyz of Bee Culture: An Encyclopedia of Beekeeping, 40th Edition. It's published by the A. I. Root Co.)
Bees--and other pollinators--gravitate toward the enticing aroma of the milkweed, too.
The milkweed is widely known as the larval host plant of the monarch butterflies--and a nectar source for the adults--but they have to share.
The broadleaf milkweed, Asclepias speciosa, in our pollinator garden draws everything from honey bees to leafcutter bees to carpenter bees.
It's almost like "Take a number." And it's especially noticeable during National Pollinator Week, a week set aside to celebrate the pollinators and to do what we can to protect them.
Recent visitors to the milkweed have included:
- A male Valley carpenter bee, Xylocopa varipuncta, a green-eyed blond
- A female Valley carpenter bee, Xylocopa varipuncta, solid black
- Honey bee, Apis mellifera
- Male leafcutter bee, Megachile sp.
And, of course, the monarchs (Danaus plexippus)!
From her post at Texas A&M University, located at College Station, 90 miles northwest of Houston, Christine Merlin basically has a front-row seat for the monarch butterfly migration.
She sees them heading to Mexico to overwinter, and she sees them returning.
But it's the science that drives her.
Merlin, an assistant professor in the Department of Biology, will speak on "The Monarch Butterfly Circadian Clock: from Clockwork Mechanisms to Control of Seasonal Migration" from 12:10 to 1 p.m., Wednesday, June 1 in Room 230 of Wellman Hall.
The seminar, sponsored by the UC Davis Department of Entomology and Nematology, will be hosted by assistant professor Joanna Chiu. It is open to all interested persons. Plans are to record it for later posting on UCTV.
"The eastern North American monarch butterfly (Danaus plexippus) has emerged as a powerful model system to study animal circadian clocks and their role in an unconventional output, the photo period-induced long-distance migration," Merlin says in her abstract.
"Circadian clocks are endogenous 24-hour timekeepers that coordinate nearly all of the animal physiology and behavior to its environment to tune specific activities at the most advantageous time of the day. Monarchs use a circadian clock to navigate to their overwintering sites during their seasonal long-distance migration. The clock time-compensates for the movement of the sun across the sky over the course of the day and regulates the sun compass output in the brain. Circadian clocks could also be used to time the monarch seasonal departure from their breeding grounds, and consequently regulate the genetic/epigenetic program controlling migratory physiology and behavior."
"I will discuss progress that our lab has made in developing reverse-genetics in the monarch butterfly to unlock its potential as a genetic model system to study animal clockwork mechanisms and the involvement of the circadian clock in insect photoperiodic responses," she says. "And if we can show this is the case and that the circadian clock is involved, we can now start to understand the genetic program that is allowing the migratory behavior."
In a Texas A&M news story, Vimal Patel described her as trying to unravel "the mysteries of the migration and the role of internal clocks in the process."
"It's incredible how such a fragile insect can complete a long-range migration so demanding," Merlin told Patel. "Every piece of it fascinates me, from how it occurs to why they go precisely where they go."
An excerpt from Patel's piece:
"While she was a postdoctoral researcher at the University of Massachusetts Medical School in the laboratory of Prof. Steven Reppert, Merlin and colleagues showed that the clocks necessary for flight orientation lie in the creatures' antennae --a departure from the previous conventional wisdom that the brain controlled the mechanism, given that it controls behavioral rhythmicity in virtually every other animal, including humans.
"The conclusion stemmed from Merlin's and her co-workers' collective curiosity concerning a decades-old anecdote. Around 50 years ago, entomologist Fred Urquhart found that Monarchs became disoriented after he clipped off their antennae. Since then, it had remained just a suspicion until the Massachusetts team confirmed it with more rigorous research."
"The team's experiment exploited technology in a way Urquhart, who merely observed the Monarchs in flight, could not at the time. They used a plastic barrel-like device called a Mouritsen-Frost flight simulator in which a butterfly is connected by tungsten wire to an output system that indicates which direction it is flying. The results were clear: The antennae-less Monarchs flew in every which direction, while those with intact antennae flew southwesterly, the migratory direction."
Merlin points out that "Migration begins every year in the fall, when the day lengths change. The shortened day lengths might be a cue for the monarchs to start their migration. And if we can show this is the case and that the circadian clock is involved, we can now start to understand the genetic program that is allowing the migratory behavior."
A native of France, Merlin received her bachelor's, master's and doctoral degrees majoring in animal biology, invertebrate physiology and insect physiology, respectively, at the University Paris 6 Pierre and Marie Curie in France. She accepted a postdoctoral fellowship at the University of Massachusetts in 2007.
Good news: The first day of spring.
Bad news: The future of the Eastern, migratory population of the monarch butterflies.
Research published today in Scientific Reports indicates there's a "quasi-extinction risk" for the Eastern, migratory population of monarch butterflies (Danaus plexippus).
A nine-member team, led by Brice X. Semmens of the Scripps Institution of Oceanography, UC San Diego, noted that the Eastern, migratory population has declined by more than 80 percent over the last decade. "The monarch's multi-generational migration between overwintering grounds in central Mexico and the summer breeding grounds in the northern U.S. and southern Canada is celebrated in all three countries and creates shared management responsibilities across North America," they wrote in their abstract.
"...We find that, given a range of plausible quasi-extinction thresholds, the population has a substantial probability of quasi-extinction, from 11–57 percent over 20 years, although uncertainty in these estimates is large."
The world population of monarchs dipped from 1 billion in the mid-1990s to about 150 million monarchs today, estimates show. The authors noted that "the vast majority of the remaining monarchs live in the eastern portions of Canada, the United States and Mexico."
The researchers blamed the loss of breeding habitat as the major cause for the decrease in the United States.
Monarch lay their eggs only on milkweed, and caterpillars eat only milkweed. Other threats: habitat loss in the Mexican overwintering sites, climate change, insecticides, mowing regimes, invasive species, and diseases.
What to do? There's a movement afoot to place the monarch on the Fish and Wildlife Service's threatened or endangered species list.
Meanwhile, the key solution is to create and restore monarch breeding habitat, the researchers said.
It would be a shame to lose the mighty monarch.