- Author: Kathy Keatley Garvey
The more we know about monarch butterflies, the better we can understand them and help conserve them.
Newly published research on California's overwintering monarch butterflies (Danaus plexippus) confirmed many previous migratory studies, but found some unexpected and surprising patterns of movement, said lead researcher Louie Yang, a community ecologist with the UC Davis Department of Entomology and Nematology.
The study, “Intra-Population Variation in the Natal Origins and Wing Morphology of Overwintering Western Monarch Butterflies (Danaus plexippus)," published in the early online version of the journal Ecography, examined the natal origins, or “birthplaces,” of butterflies at four California overwintering sites.
It will be incorporated into an online issue, perhaps within six months, but it has not yet been assigned to an issue, said journal managing editor Maria Persson.
Natal origins of butterflies collected from the two northern sites--Lighthouse Field State Beach and Moran Lake, both in Santa Cruz County--varied significantly from those collected at the two southern overwintering sites--Pismo State Beach, San Luis Obispo County; and the Coronado Butterfly Preserve, Santa Barbara County, they said.
“We hope that this paper improves our understanding of where monarch butterflies grow up in western North America,” said Yang, an associate professor. “This study uses a naturally occurring continental-scale pattern of hydrogen isotopes in precipitation in order to estimate the natal origins of overwintering butterflies. Building a clearer understanding of where they come from could help us better understand many aspects of their ecology.”
The research is the work of Yang; Dmitry Ostrovsky of the University of Colorado, Denver; and Matthew Rogers and Jeffery Welker of the University of Alaska.
The research team set out to answer two key questions: “How do broad geographic areas of potential natal habitat contribute to the overwintering population of western monarch butterflies in California?” and “How does the individual variation in the wing morphology of overwintering western monarch butterflies correlate with estimated migratory distance from their natal origins?”
They first compared the wings of 114 monarch butterflies collected from the four overwintering sites with a continental-scale monarch butterfly wing isoscape derived from the U.S. Network for Isotypes in Precipitation (USNIP) database. They used spatial analyses of stable isotype ratios and correlations with wing morphology. Then they examined the correlations of monarch butterfly forewing size and shape.
Of the 114 butterflies sampled, they found that 30 percent developed in the southern coastal range; 12 percent in the northern coast and inland range; 16 percent in the central range, and 40 percent developed in the northern inland range.
“Interestingly, the two most northern overwintering sites in the study showed the largest contributions from the southern coastal range (Lighthouse Field, 45 percent; Moran Lake, 37 percent; Pismo Beach, 22 percent; and Coronado Preserve, 24 percent) while the two most southern overwintering sites showed the largest contributions from the northern inland range (Lighthouse Field, 30 percent; Moran Lake, 35 percent; Pismo Beach, 53 percent; and Coronado Reserve, 39 percent),” they wrote.
The researchers randomly collected the monarchs Dec. 4-6, 2009 from aggregations in trees. The collecting resulted in: 19 males and 9 females from Coronado; 22 males and 8 females from Pismo State Beach; 20 males and 10 females from Moran Lake; and 18 males and 8 females from the Lighthouse Field State Beach.
In addition, the male monarch butterflies showed mean total masses that were 5.8 percent larger than those of the females.
The monarch butterfly of North America overwinters along the California coast and in the central mountains of Mexico. Previous studies have indicated that the western monarchs or those from natal habitats west of the Rocky Mountains, overwinter along the California coast. Those that develop east of the Rockies overwinter in central Mexico.
The project was funded in part by a National Science Foundation (NSF) Early Career Development Program grant awarded to Louie Yang, and a NSF Major Research Instrumentation Program grant awarded to Jeffrey Welker.
(Note: For more information on monarchs, read the Xerces Society's website. Xerces also encourages us all to plant milkweed. See Project Milkweed.)
- Author: Kathy Keatley Garvey
The tachinid fly is a parasitoid.
What's a parasitoid? And where can you go to learn about it?
"An insect parasitoid is a species whose immatures live off of an insect host, often eating it from the inside out," said Tabatha Yang, education and outreach coordinator of the Bohart Museum of Entomology, University of California, Davis. "It is part of their life cycle and the host generally dies."
Want to know more about them? You're in luck. The Bohart Museum will host “Parasitoid Palooza II” at its open house from 1 to 4 p.m., Sunday, Jan. 10 in Room 1124 of the Academic Surge Building on Crocker Lane. It's free and open to the public.
Senior museum scientist Steve Heydon, a global expert on jewel wasps, will give a 15-minute presentation on parasitoids and the group that he studies--the jewel wasps (Pteromalidae). His talk is from 2 to 2:15.
Rosemary Malfi, a postdoctoral fellow in the Neal Williams lab in the UC Davis Department of Entomology and Nematology, will present a mini talk from 3 to 3:15 on some of the parasitoids she has worked with while completing her doctorate. She did extensive work on the interaction between conopid flies and bumblebee hosts.
Another group of parasitoids that will be highlighted at Sunday's open house will be the Strepsiptera, or twisted-wing parasites, an order of insects that the late UC Davis entomologist Richard M. Bohart (1913-2007) researched for his doctorate in 1938. Both the Bohart Museum and an entire family of Strepsiptera, the Bohartillidae, are named in honor of Professor Bohart.
The Bohart Museum, directed by Lynn Kimsey, professor of entomology at UC Davis, houses a global collection of nearly eight million specimens. It is also the home of the seventh largest insect collection in North America, and the California Insect Survey, a storehouse of the insect biodiversity.
Special attractions include a “live” petting zoo, featuring Madagascar hissing cockroaches, walking sticks and a rose-haired tarantula named “Peaches.” Visitors are invited to hold the insects and photograph them. The museum's gift shop, open year around, includes T-shirts, sweatshirts, books, jewelry, posters, insect-collecting equipment and insect-themed candy.
The Bohart Museum holds special open houses throughout the academic year. Its regular hours are from 9 a.m. to noon and 1 to 5 p.m. Mondays through Thursdays. The museum is closed to the public on Fridays, Saturdays and Sundays and on major holidays. Admission is free.
Upcoming open houses are:
- Saturday, Feb. 13: noon to 4 p.m.: Part of Biodiversity Museum Day
- Saturday, April 16, 10 a.m. to 3 p.m.: UC Davis Picnic Day
- Saturday, July 31, 8 to 11 p.m.: “Celebrate Moths.”
More information on the Bohart Museum is available by contacting (530) 752-0493 or emailing bmuseum@ucdavis.edu or Tabatha Yang at tabyang@ucdavis.edu.
- Author: Kathy Keatley Garvey
Science journalist Janet Marinelli, writing in Yalee360, said it well in her Dec. 21st piece, "To Protect Monarch: a Plan to Save the Sacred Firs."
This should be widely read, widely distributed and widely discussed.
Basically, it's crucial to plant milkweed, the host plant of the besieged and dwindling monarch, but it's also crucial to plant more oyamel fir trees (Abies religiosa) in central Mexico, where deforestration and climate disruption and loss of milkweed combine to rage an ongoing war against the migrating monarchs. These firs are the favorite of overwintering monarchs that migrate from the Eastern United States, and as far away as Canada.
This tree is called a sacred fir ”because of its narrow, conic tip that resembles clasped hands with fingers pointed upwards, praying," Marinelli writes. "These dense, dark-green conifers protect the monarchs from cold and rainy winter nights."
Says Wikipedia: "Sacred fir is named after the use of cut foliage in religious festivals in Mexico, notably at Christmas. It is also the preferred tree for the monarch butterfly (Danaus plexippus) to reside in colonies during its hibernation in Mexico. The distribution of this tree is narrowing because of deforestation and human impact."
The fir is on the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species.
"A billion butterflies once fluttered down from as far as southern Canada to paint the firs a quivering crazy quilt of orange and black with white spots," Marinelli eloquently wrote. "But due to the usual litany of destructive factors — from the deforestation of Mexico's oyamel fir trees to the loss of milkweeds, the primary host plants for monarch caterpillars up north — their numbers have plummeted. By 2014, there were just 33 million of them "
So the scientists in Mexico seek to plant these trees at higher altitudes--not just to save this species of trees, but to save the monarchs.
Cuauhtémoc Sáenz-Romero, a forest geneticist at the Universidad Michoacana de San Nicolás de Hidalgo, and the plan's architect, was saying: “We have to act now. Later will be too late, because the trees will be dead or too weak to produce seeds in enough quantity for large reforestation programs.”
Agreed. It's important to act now. "Later will be too late." Saving the sacred firs is a crucial tool in the save-the-monarch toolbox.
Humankind, so apt at destroying habitat instead of protecting it, now needs to backtrack and save the environment, the firs and the monarchs.
Before. It. Is. Too. Late.
- Author: Kathy Keatley Garvey
Not all monarch butterflies that you rear will make it.
Such was this case this week with when two monarchs eclosed, both crippled and struggling to survive. The damage to their crumbled wings may have occurred when, as jade-green chrysalids, they fell to the floor of the mesh butterfly habitat. We gently picked them up, tied dental floss around each cremaster, and hung them back up again in a scene reminiscent of Christmas stockings hung by the fireplace.
No. 21 eclosed. Then No. 22. But these monarchs, the last of the season, needed names instead of numbers.
The first one we named "Tiny." The second one, "Tim." They were named after the fictional character, Tiny Tim, from the 1843 novel A Christmas Carol by Charles Dickens. Tiny Tim couldn't walk but he brought joy to the Bob Cratchit family and he changed the heart of Ebenezer Scrooge.
Life is as good as can be expected. We're rolling cotton balls in a sugar/water mixture (with a dash of soy sauce for vitamins and minerals) and they're eating. They're climbing on the lantana blossoms during the day. At night they scurry to a roost at the top of the habitat and remain there until morning.
Yesterday, we took them outside and placed them on the spokes of a miniature penny-farthing (big wheel bicycle). They soaked up the warmth of the afternoon sun and seemed energized. But when they tried to fly, they tumbled to the ground. Maybe due to Ophryocystis elektroscirrha (OE)?
Now they're back inside the house, cozy in their butterfly habitat with the fresh lantana and newly soaked cotton balls and Adele singing "Hello" on the CD.
They're not going to make it. We know that. They can flutter but they cannot fly. They can feel the warmth of the sun but they'll never migrate, overwinter and feel another warmth--the warmth of a cluster at the top of an 80-foot eucalyptus tree.
Butterfly guru Art Shapiro, distinguished professor of evolution and ecology at UC Davis, said it best: "Life is hard."
Yes, it is.
About 1 percent of caterpillars make it to adults, he said.
- Author: Kathy Keatley Garvey
Is the overwintering monarch butterfly population along California's coast increasing or decreasing?
"So far, far the picture is rather mixed for the number of monarchs in California," according to Matthew Shepherd, communications director for the Xerces Society for Invertebrate Conservation. "More than 130 sites have been surveyed," he told us today. "Northern sites have more butterflies that last year, other sites fewer, and there are many southern sites that haven't yet reported data. A full analysis will be available in January."
The western monarchs, that is those that west of the Rockies, migrate to the California coast to overwinter while the eastern monarchs head to the mountains of central Mexico.
In a news release issued today from its headquarters in Portland, Ore., the Xerces Society said that early data from its Western Monarch Thanksgiving Count suggests "a small increase in butterfly numbers in some parts of the overwintering range."
That is, 2015 may have "been a better year for the beleaguered monarch butterfly in the western United States."
"The overall population size is still far lower than it was in the 1990s, when more than one million butterflies were counted," the news release said. "The surveys indicate that sites north of Santa Cruz are hosting more butterflies than previous years, whereas sites in Monterey, San Luis Obispo, and Santa Barbara counties are reporting fewer numbers of butterflies on average. Several new sites have been reported, including some from Marin County with up to 10,000 monarchs. The data is not yet available for Santa Cruz County and southern California."
The Xerces Society launched its Western Monarch Thanksgiving Count in 1997. This year some 85 volunteers surveyed more than 130 sites over a three-week period centered around Thanksgiving.
We'll all have to wait until January to see the final tallies.
Meanwhile, we were happy to see monarchs roosting in November in the Berkeley Aquatic Park (for the first year ever) and on Mare Island, Vallejo, (maybe also first?) but those clusters may be temporary. As butterfly guru Art Shapiro, distinguished professor of evolution and ecology at the University of California, Davis, says--they may move on as soon as the weather turns foul.
Maybe they're on their way to Santa Cruz?
"There are some sites where monarchs gather in fall, almost like staging posts in preparation for moving to overwintering locations," Shepherd told us.
Be sure to read the Xerces Society blog by Sarina Jepson, endangered species program director of the Xerces Society, and the news release issued by Xerces Society.
Where can you observe the overwintering monarchs in California? The Xerces Society has kindly provided a web page with links to overerwintering sites in Alameda, Santa Cruz, Monterey, San Luis Obispo and Santa Barbara counties.