No, the stuffed turkey didn't slip out of the oven and fall on the floor. Nor did the pumpkin pie turn another shade of orange.
Some unexpected guests arrived--four to be exact.
That's the number of monarch caterpillars we found on our tropical milkweed (Asclepia curassavida) in our pollinator garden in Vacaville, Calif.
Between Nov. 15 and Nov. 24, we've discovered 12 caterpillars on our tropical milkweed, a non-native perennial. (Three other species of milkweed, Asclepias tuberosa, Asclepias speciosa, and Asclepias fascicularis, also thrive in our pollinator garden.)
Just when we thought our small-scale conservation project of rearing and releasing monarchs is all over 'til next year, it's not. Our season total of 54 monarchs is likely to increase.
"This is really far inland for such late breeding," said butterfly expert Art Shapiro, distinguished professor of evolution and ecology who has been studying Central California butterflies for more than four decades and maintains a website on his work and monitoring observations. "Winter breeding has been occurring near the coast for some years now, but I recall no records this late east of the East Bay. October, yes. November? We really need to understand the physiology and genetics of non-repro-diapausing winter monarchs!"
"We've been seeing evidence of a significant fall window of opportunity for larval monarch development for a few years now, which seems different than the historical pattern," noted Louie Yang, associate professor of entomology, UC Davis Department of Entomology and Nematology. "I've wondered if these are returning migrants that are breaking reproductive diapause when they encounter warm conditions in the Valley. I've mostly seen them on late season native milkweeds, but of course the tropical milkweeds are even more persistent."
Meanwhile, the 12 monarchs are the center of attention--well, at least a corner of attention--on our kitchen counter. Our setup: two mesh, zippered containers from the Bohart Museum of Entomology, UC Davis; and four narrow-necked, flat-bottomed bottles filled with water and milkweed stems.
The monarch caterpillars are doing what monarch caterpillars do best--and what folks around the Thanksgiving dinner table do best. Eat.
Forget the soaps; let's talk about soapberry bugs and an entomologist at the University of California, Davis, who studies them.
And why and how she decided to pursue entomology as a career. That we'll save until the end of this blog.
Doctoral candidate Meredith Cenzer of the Louie Yang lab, UC Davis just published her research on soapberry bugs, which are a classic evolutionary example of how rapidly insects can switch hosts, adapting from a native to an invasive plant.
Her research shows that soapberry bugs have not only lost adaptations to their native host plant but are regionally specializing on an invasive host.
The work, "Adaptation to an Invasive Host Is Driving the Loss of a Native Ecotype," published in the current edition of the journal Evolution, “collapses a classic and well-documented example of local adaptation,” said doctoral candidate Meredith Cenzer of the Louie Yang lab, UC Davis Department of Entomology and Nematology. The plant-host switch can lead to disruption of native plant communities and a breakdown of the ecosystem.
The players involved are the soapberry bug (Jadera haematoloma), also known as “the red-shouldered bug”; its native host plant, the balloon vine (Cardiospermum corindum), and the invasive host, the golden rain tree or Taiwanese rain tree (Koelreuteria elegans).
The study, which took place in Florida, expands on the 1989 groundbreaking research of UC Davis evolutionary ecologist and soapberry expert Scott Carroll, who documented local adaptation in beak length, survival, and development time and other traits between soapberry bugs, balloon vine and the golden rain tree in Florida.
Said Carroll: "Meredith Cenzer's findings carry an important message for those concerned with biodiversity conservation, because she shows that even highly distinct adaptive specializations can disappear rapidly due to human influence on the environment– even in cases where the key native habitat has not been lost."
The soapberry bug, which lives throughout the United States and much of the world, feeds on seeds within the soapberry plant family, Sapindaceae, which includes soapberries, boxelders and maples. Mostly black, it has red eyes, red lateral stripes on the sides of its head and red on its “shoulders” (pronotum). It is often mistaken for the boxelder bug.
“As part of my doctoral dissertation, I documented that this pattern of local adaptation has been lost in the last 27 years,” Cenzer said, “and that all populations of soapberry bugs in Florida-- even those still found on the native --are now adapted only to the invasive host.“
“Locally adapted populations are often used as model systems for the early stages of rccological speciation, but most of these young divergent populations will never become complete species,” Cenzer noted in her abstract. “The maintenance of locally adapted populations relies on the strength of natural selection overwhelming the homogenizing effects of gene flow; however, this balance may be readily upset in changing environments.”
“All populations that were adapted to the native host--including those still found on that host today--are now better adapted to the invasive host in multiple phenotypes,” she wrote in her abstract.” Weak differentiation remains in two traits, suggesting that homogenization across the region is incomplete. This study highlights the potential for adaptation to invasive species to disrupt native communities by swamping adaptation to native conditions through maladaptive gene flow.”
Cenzer characterized local adaptation as “high performance in one habitat coming at the cost of performance in other habitat types, such that populations specialized on each habitat will have higher fitness in that environment than immigrants from other habitats.”
“This results directly in two types of ecological reproductive isolation between locally adapted populations: 1) selection against migrants, who will be outcompeted by residents, and 2) selection against hybridization (if hybrids show intermediate phenotypes), as hybrid offspring will be outcompeted in each habitat by one parental type,” she wrote in her research paper. “However, such reproductive isolation relies on ongoing differential selection balanced with low rates of gene flow between habitats. In most well studied systems demonstrating local adaptation, we do not know how perturbation – either to selection pressures or gene flow – will influence the long-term stability of differentiation.”
Carroll, who maintains a website, “Soapberries of the World,” says the soapberry bugs are “very approachable native guides to how evolution is taking place on earth day.” His website shows “how evolution happens every day and why it matters.”
How did Meredith Cenzer, a native of Gainesville, Fla., become interested in entomology? We love her answer.
"I first became interested in entomology as a kid," she recalled. "The defining moment in my memory is when my gifted science teacher, Ms. Linda Osborne, told me in third grade that there are people who study insects for a living and that they're called entomologists. She was going to put me in timeout for being too loud (a lifelong problem), but told me she'd let it slide this time if I promised to become an entomologist."
"Two years later, she let me come in and teach her first graders about insects. For my first science fair project, in sixth grade, I tracked the progress of tent caterpillar aggregations; we weren't allowed to manipulate animals, so I photographed them every day and made notes on their behavior - my parents still have the poster from that one."
So, she promised her teacher she'd become an entomologist. And she kept her promise. She received her bachelor of science degree in entomology at the University of Florida in 2009.
Future plans, after receiving her doctorate in entomology from UC Davis?
“I am broadly interested in evolutionary ecology, particularly in plant-insect interactions, and the balancing roles of selection, gene flow, and plasticity on determining the phenotypes we see in nature,” she said. After receiving her doctorate in entomology from UC Davis in the fall, she will start a postdoctoral position at Florida State University with biology professor Leithen M'Gonigle, developing theory on the evolution of dispersal in patchy landscapes.
A tip of the insect net to Meredith Cenzer!
(Editor's Note: Meredith Cenzer participated in the Entomological Society of America's Linnaean Games competition in 2011. See Bug Squad blog of Nov. 22, 2011.)
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.
Want to develop skills that will make your application to graduate school, medical school or veterinary school really stand out from the crowd?
The UC Davis Research Scholars Program in Insect Biology is recruiting undergraduate students who are eager to experience one-on-one research training and mentorship.
This will be the third cohort of students.
The program, now officially approved by the Academic Senate, is coordinated by professor Jay Rosenheim and assistant professors Louie Yang and Joanna Chiu, all of the UC Davis Department of Entomology.
The Research Scholars Program in Insect Biology provides the opportunity to learn research skills in all areas of biology, including:
- behavior and ecology
- population biology
- mathematical bology
- human health
- cell biology
- molecular biology
Applications are now being accepted from first and second-year students and first-year transfer students. The application deadline is April 10, 2013. More information on the program and how to apply is on the program’s website.
Successful venture? Yes, indeed. Two members of the Research Scholars Program in Insect Biology recently received President's Undergraduate Fellowship Program (PUF) grants.
They are Sarah Staley, mentored by medical entomologist Anthony “Anton” Cornel, associate entomologist with the UC Davis Department of Entomology and based at the Kearney Agricultural Research and Extension Center, Parlier; and Don Hoang, mentored by evolutionary geneticist Artyom Kopp, professor in the Department of Evolution and Ecology.
Staley and Hoang were among 25 undergraduate students receiving grants from a pool of 62 applicants. Staley submitted her proposal titled “Prevalence of Leucocytozoa Infections in Potential Vector Populations of Black Flies in Alaska.” Hoang's proposal: "The Yeast/Drosophila Relationship: Is it Meant to Last?”
Read their story on the UC Davis Department of Entomology website.
No small feat. Great things are happening in the Research Scholars Program in Insect Biology. Jay Rosenheim, Louie Yang and Joanna Chiu are making it happen.
"When we try to pick out anything by itself, we find it hitched to everything else in the Universe."--John Muir, My First Summer in the Sierra
Ecologist Louie Yang of the UC Davis Department of Entomology, tags that quote at the end of each email.
On that note, did you catch the Feb. 14th National Public Radio piece on "Why California Almonds Need North Dakota Flowers (And a Few Million Bees)?"
"Here's the web of connections: a threat to California's booming almond business; hard times for honey bees in North Dakota; and high corn prices," Dan Charles said.
The gist of it:
Every year, bees from 1.6 million of the nation's hives are trucked into California to pollinate the 750,000 acres of almonds. Since the almond pollination season is brief--a few weeks in mid-February--the bees need someplace to thrive after the bloom ends. Many beekeepers head to North Dakota's federally funded government program, the Conservation Reserve Program, where flowers bloom all summer long. Basically, Uncle Sam leases land from the farmers to help the bees thrive.
Now, however, North Dakota farmers are finding it more profitable to grow corn than put their land in the Conservation Reserve Program.
"The amount of North Dakota land in the Conservation Reserve, meanwhile, has declined by a third over the past five years," said Charles. "This year, it's expected to take another plunge, perhaps down to half what it was its peak."
So, bottom line, California almonds--and the nation's bees--are tied to the North Dakota's Conservation Reserve Program.
As Charles correctly pointed out: "This is not just a beekeeper's problem anymore. ...the prosperity of almond growers...depends on what happens to bees on the lonely northern Plains."
To get a really good grasp of the situation, read Hannah Nordhaus' excellent book, "The Beekeeper's Lament: How One Man and Half a Billion Honey Bees Help Feed America."
NPR interviewed some of the very migratory beekeepers that Nordhaus interviewed.