Posts Tagged: Monarch butterflies
The Xerces Society for Invertebrate Conservation issued news today that is both disturbing and hopeful.
Disturbing in that the monarch butterfly population (Danaus plexippus) has declined by more than 90 percent in under 20 years.
Hopeful in that the monarch may receive federal protection through the Endangered Species Act.
The Xerces Society, the Center for Biological Diversity, the Center for Food Safety, and monarch scientist Lincoln Brower, have filed a legal petition with the U.S. Fish and Wildlife Service to protect the monarch through the Endangered Species Act. The agency must respond within 30 days as to whether the petition warrants further review.
“Monarchs are in a deadly free fall and the threats they face are now so large in scale that Endangered Species Act protection is needed sooner rather than later, while there is still time to reverse the severe decline in the heart of their range,” related Lincoln Brower, preeminent monarch researcher and conservationist, who has been studying the species since 1954.
Tragicallly, the monarchs have lost more than 165 million acres of habitat, including nearly a third of their summer breeding grounds that contain their host plant, milkweed. The female monarchs lay their eggs on milkweed and this is the only food their larvae eat.
As Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis, told us today: "Might be too little too late but they have to preserve/conserve milkweeds (Asclepias spp.) That's more important than the butterfly itself."
Xerces earlier sounded the alarm on the critical role that milkweeds play in the monarch's life cycle.
Senior scientist Tierra Curry of the Center for Biological Diversity, hammered home this point in the news release: “The 90 percent drop in the monarch's population is a loss so staggering that in human-population terms it would be like losing every living person in the United States except those in Florida and Ohio.”
And the loss of habitat is equal in size to the state of Texas.
The news release said that the butterfly's dramatic decline is "being driven by the widespread planting of genetically engineered crops in the Midwest, where most monarchs are born. The vast majority of genetically engineered crops are made to be resistant to Monsanto's Roundup herbicide, a uniquely potent killer of milkweed, the monarch caterpillar's only food. The dramatic surge in Roundup use with Roundup Ready crops has virtually wiped out milkweed plants in midwestern corn and soybean fields."
Science policy analyst Bill Freese of the Center for Food Safety was quoted as saying: "The widespread decline of monarchs is driven by the massive spraying of herbicides on genetically engineered crops, which has virtually eliminated monarch habitat in cropland that dominates the Midwest landscape. Doing what is needed to protect monarchs will also benefit pollinators and other valuable insects, and thus safeguard our food supply.”
Monarch butterflies are known for their spectacular multigenerational migration each year from Mexico to Canada and back, the news release said.
"The population has declined from a recorded high of approximately 1 billion butterflies in the mid-1990s to only 35 million butterflies last winter, the lowest number ever recorded," according to the release. "The overall population shows a steep and statistically significant decline of 90 percent over 20 years. In addition to herbicide use with genetically engineered crops, monarchs are also threatened by global climate change, drought and heat waves, other pesticides, urban sprawl, and logging on their Mexican wintering grounds. Scientists have predicted that the monarch's entire winter range in Mexico and large parts of its summer range in the states could become unsuitable due to changing temperatures and increased risk of drought, heat waves and severe storms."
Endangered species director Sarina Jepson of the Xerces Society worries--and rightfully so--that the monarch may become extinct, just like the passenger pigeon.
We are, too. We've seen only two--two--of these majestic butterflies fluttering in our family bee garden this year.
Monarch butterfly nectaring on Mexican sunflower, Tithonia, as a territorial male longhorned bee, Melissodes agilis, takes aim. (Photo by Kathy Keatley Garvey)
Monarch butterfly heading toward a butterfly bush. (Photo by Kathy Keatley Garvey)
This is milkweed, the monarch's host plant. (Photo by Kathy Keatley Garvey)
Folks are planting milkweed for the monarchs.
The milkweed (genus Asclepias) is the host plant (larval food) for the monarch butterfly (Danaus plexippus). No wonder the monarch is sometimes called "the milkweed butterfly."
The perennial plant is so named for its milky juice, consisting of a latex containing alkaloids and other complex compounds. Carl Linnaeus named the genus for the Greek god of healing, Asciepius.
But milkweed is also a favorite bee plant. It's an important nectar source.
The UC Davis Arboretum has a beautiful milkweed patch near Mrak Hall and on any given day, you'll see honey bees foraging. Be prepared to see as many as four or five honey bees on one bloom. The fragrance is delightful and so are the bees!
Honey bee foraging on milkweed in the UC Davis Arboretum, near Mrak Hall. (Photo by Kathy Keatley Garvey)
Walk down the garden path, lined with milkweed, and sit on the bench in the UC Davis Arboretum. (Photo by Kathy Keatley Garvey)
If not, monarch butterflies are in a heap of trouble.
An interesting study just published in journal PLOS One by researchers at the University of Jamestown, North Dakota, and the University of Georgia, Athens, Georgia, revealed that the larvae of monarch butterflies that skip meals (host plant, milkweed) will become adults with a smaller wing size, as much as 2 percent smaller.
That's important because monarch butterflies (Danaus plexippus) are migratory animals that travel long distances, and without milkweed, Asclepias spp., their migration will be adversely affected.
In their research, “Does Skipping a Meal Matter to a Butterfly's Appearance? Effects of Larval Food Stress on Wing Morphology and Color in Monarch Butterflies,” Haley Johnson of the University of Jamestown and her colleagues also found that monarch larvae deprived of food became adults with a different wing coloration: paler wings.
This study nails home the point why we need to plant milkweed. As the Xerces Society for Invertebrate Conservation says on its website: “The loss of milkweed plants in the monarch's spring and summer breeding areas across the United States is believed to be a significant factor contributing to the reduced number of monarchs recorded in overwintering sites in California and Mexico. Agricultural intensification, development of rural lands, and the use of mowing and herbicides to control roadside vegetation have all reduced the abundance of milkweeds in the landscape.”
To address this seed shortage, the Xerces Society launched Project Milkweed to produce new sources of milkweed seed “where seed has not been reliably available: California, the Great Basin, Arizona, New Mexico, Texas, and Florida."
Bottom line, the Xerces Society is:
- raising public awareness about milkweeds' value to monarchs and native pollinators
- promoting the inclusion of milkweeds in habitat restoration efforts
- developing milkweed seed production guidelines, and
- building new markets for milkweed seed.
The Xerces website also offers sources of native milkweed seed in your state.
Meanwhile, the butterflies that overwintered in Mexico are on the move and in Texas. For more information on butterfly migration, see Monarch Butterfly, Journey North.
Monarch butterfly sightings are becoming more uncommon. (Photo by Kathy Keatley Garvey)
Monarch butterfly grabbing a sip of nectar from lantana. (Photo by Kathy Keatley Garvey)
Monarchs and milkweed are in the news again.
As well they should be.
The declining monarch population, coupled with the decreasing scarcity of their host plant, the milkweed, is disturbing. The larvae of the monarch butterfly (Danaus plexippus) feed exclusively on milkweeds. No milkweed, no monarchs.
Butterfly expert Art Shapiro, distinguished professor of evolution and ecology at UC Davis, says the problem hasn't totally reached California yet. "The 'dearth of milkweed' problem is primarily an East/Midwest problem, due to increased use of Roundup since the introduction of 'Roundup-ready' GM crops. It's quite real. There is no such problem out here--at least yet--but there is a new milkweed pathogen that may cause one! Dave Rizzo (UC Davis Department of Plant Pathology) and I hope to publish on it shortly. No harm in planting milkweeds, but the problem isn't a California one, at least not yet."
Journalist-photographer Alessandra Bergamin, writing in the Feb. 18 edition of Bay Nature: Exploring Nature in the San Francisco Bay Area, says that "the number of monarchs overwintering in Mexico's Oyamel fir forest has reached an all-time low," quoting the World Wildlife Fund in Mexico. "The reports suggest that factors such as loss of habitat, climate change and use of insecticides have contributed to the decline."
The situation in California, however, looked better than bleak last year. A little better. "Monarch butterfly populations in California's coastal overwintering sites showed a slight — and surprising — rebound in 2013 after more than a decade of dwindling numbers," Bergamin wrote. "The 2013 Western Monarch Thanksgiving Count tallied 211,275 monarchs at 162 sites from Sonoma County to San Diego County, up from 144,812 the year before."
Over the past two decades, however, the Western monarch population has dramatically declined in California, she pointed out in her article, "Western Monarch Population Hanging On." The downward trend is expected to continue.
Meanwhile, the Xerces Society for Invertebrate Conservation, headquartered in Portland, Ore., has posted a seed finder resource so folks can find milkweed seed in their state and plant the seeds in their gardens, parks, landscapes, restoration areas and on farms.
Oakland parks supervisor Tora Rocha is taking it one step further. She is collecting the monarch caterpillars, rearing them, and releasing the adults in the Lakeside Gardens at Lake Merritt. Her newly formed Pollinator Posse has sparked the interest of volunteers, who range from school children to city council members. They all want to save the monarchs.
Rocha bans pesticides and herbicides from her pollinator gardens. “For the past fifteen years the gardens have had a pesticide-and herbicide-free policy,” Rocha told writer Constance Taylor of Wild Oakland, which offers free, Oakland-centered environmental education. “We also rely on volunteers contributing thousands of hours to keep our parks maintained--about 75% of the work is done by volunteers.”
Rocha says it's not enough to be a custodian of the land: it's important to be a steward of the land and protect the pollinators. She's created a video, posted on YouTube, that explains what she and the other Pollinator Posse members do.
Rocha and colleague Eddie Dunbar of the Insect Sciences Museum of California and a fellow Pollinator Posse member, recently visited UC Davis to share information with Shapiro and native pollinator specialist Robbin Thorp, emeritus professor of entomology.
Another person keen on butterflies is Sally Levinson of Berkeley, who writes a blog on butterflies and is publishing educational videos, including "Secret Lives of Monarchs" and "In the Company of Wild Butterflies." As a graduate student at UC Riverside, Levinson studied with major professor Bruce Hammock, now a distinguished professor of entomology at UC Davis. (He maintains a joint appointment with the Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center.)
As an aside, the Bohart Museum of Entomology at UC Davis offers a "Got Milkweed?" t-shirt spotlighting the monarch and its host plant. The work of doctoral candidate Fran Keller and Bohart volunteer/naturalist Greg Kareofelas, the t-shirt is available online or at the museum, located in Room 1122 of the Academic Surge building on Crocker Lane.
Want monarchs? Plant milkweed.
A monarch butterfly nectaring on a zinnia. (Photo by Kathy Keatley Garvey)
This is a milkweed, the host plant of the monarch. This photo was taken in the Melissa Garden, Healdsberg. http://www.themelissagarden.com/ (Photo by Kathy Keatley Garvey)
As the world mourned the Jan. 27th death of 94-year-old folk singer Pete Seeger and hummed his signature song, "Where Have All the Flowers Gone?", the question has now turned to: "Where Have All the Monarchs Gone?"
The monarch butterfly (Danaus plexippus) is in trouble.
It has been in trouble for a long time.
Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis, says the monarch situation is not surprising, really, due to "changing ag practices, urbanization and drought/freezing."
Monarchwatch.org reported today that "the overwintering numbers are in from Mexico and once again it's bad news."
In his blog, Chip Taylor mentions three factors have "contributed significantly to the loss of monarch and pollinator habitats: the adoption of herbicide tolerant (HT) crops, the ethanol mandate, and development."
"In much of the corn-belt," Taylor wrote, "farming is from road to road with little habitat for any form of wildlife remaining. Grasslands--including some of the last remaining native prairies, rangelands, wetlands, and 11.2 million acres of Conservation Reserve Program (CRP) land--have been plowed under to produce more corn and soybeans. Most of these acres formerly contained milkweeds, monarchs, pollinators and other forms of wildlife. They are gone and the total loss of these habitats since 2008 exceeds 24 million acres (an area about equal to the state of Indiana)."
Milkweed is the monarchs' host plant.
"Development consumes about a million acres of farmland a year," Taylor noted, "and the conversion of woodlands and other landscapes to shopping malls, housing and roadways consumes another million acres a year. Overall, the loss of various habitats due to development probably exceeded 34 million acres since 1996."
Taylor estimates that "that at least 167 million acres of monarch habitat has been lost since 1996."
"Not all of the corn and soybean acreage occurs within the summer breeding range for monarchs so the total loss of monarch habitat due to HT crops is lower (150 million) than the total area (174.5 million) planted in 2013. The 24 million acres of grasslands, etc. converted to croplands since 2008 have been included in the estimated loss to HT crops. Add to this number the estimated loss due to development and the total is 167 million acres lost but this could easily be an underestimate since there are losses such as roadside management that we can't account for."
Be sure to read his informative blog, and his charts. Taylor ends with "...let's plant milkweed--lots and lots of it."
The Xerces Society of Invertebrate Conservation's Project Milkweed is raising public awareness and promoting the use of milkweeds in restoration habitats. Xerces' role also includes developing milkweed seed production guidelines and building new markets for milkweed seed, according to its website.
Monarch butterfly nectaring on lantana on Oct. 27, 2013 in Vacaville, Calif. (Photo by Kathy Keatley Garvey)
A glorious sight: monarch on the move. (Photo by Kathy Keatley Garvey)