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.)
Ah, soapberry bugs...
They'll never get top billing in a racy novel, let alone star in an R-rated movie.
The "R" word comes into play only when they're referred to as "the rapidly evolving soapberry bugs" or when scientists talk about reproduction.
Evolutionary ecologist Scott Carroll of the UC Davis Department of Entomology and Nematology is a soapberry scientist. In fact, he is the "resident soapberry scientist" behind the spectacular website, "Soapberry Bugs of the World." Scott, who holds a doctorate in biology from the University of Utah, directs the UC Davis-based Institute for Contemporary Evolution, which "observes and experiments with patterns of ongoing evolution in wild and anthropogenic environments."
Explore the soapberry website--it's the work of Carroll, Crystal Perreira and Trevor Fowels--and you'll learn all about these insects.
"Small but powerful, soapberry bugs are quickly adapting as humans alter the world," Carroll writes on the website. "These beautiful insects artfully show how evolution happens every day and why it matters."
"Here at soapberrybug.org, we are collecting and integrating the world's information on all 65 species of soapberry bugs. We present this information in a variety of formats accessible to students, scientists, and anyone with interest."
Soapberry bugs belong to the order Hemiptera, often known as the true bugs. "Their lack of relatively well-developed scent glands places them in the family Rhopalidae," Carroll says. "Soapberry bugs specifically encompass all species within the subfamily Serinethinae. Serinethinae contains three genera: Jadera, Leptocoris, and Boisea."
They encourage you to check out their website:
• Comics, videos, and photos
• Identification guides
• Research results and scientific papers
And if you see soapberry bugs, you're welcome to send your observations to the soapberry scientists.
Well, on a glorious spring day at the UC Davis Arboretum's Storer Garden, we saw about 50 of these intriguing bugs. Fifty Shades of Gray (and Red). They were looking for mates on a tree trunk. Up, down, around. Repeat. Up, down, around. Well, hello, there!
The "R" word came into play: reproduction.
"The soapberry bug life cycle seems straightforward: male and female mate, the female lays eggs, the young hatch from the eggs, grow, and cast off their skin (molt) as they go through several developmental stages called instars" Carroll says. "Finally, adulthood (along with a fully developed set of wings) and reproductive maturity are achieved and the cycle begins again. However, several aspects of this cycle are more complex than they initially appear. Firstly, just because a male mates with a female, does not necessarily mean that he will father her offspring. In soapberry bugs (and many other organisms), the sperm of the male that was the last to mate with the female has precedence over the sperm deposited by those that mated with her previously. Thus, natural selection favors males with the behavior, morphology, and physiology that increase the chance that they will be the last male to mate with any given female before she lays her eggs. This phenomenon inevitably contributes to reproductive competition between males."
There you have it. No soap opera. No romance. No playing around. Just 50 Shades of Gray (and Red).
The mutual adaption of native and non-native species is changing best practices for promoting biodiversity, acknowledges UC Davis evolutionary ecologist Scott Carroll, founding director of the Institute for Contemporary Evolution and a member of the Sharon Lawler lab, UC Davis Department of Entomology and Nematology.
What can we do? Scott advocates interdisciplinary solutions.
Carroll will discuss “An Approach to Conservation that Reconciles Past, Present and Future Landscapes in Nature” at 6 p.m., Thursday, Jan. 30 at the Commonwealth Club of California, located at 595 Market St., San Francisco. This is part of the ongoing forum topic, “Science of Conservation and Biodiversity in the 21st century.”
A networking reception begins at 5:30 p.m., followed by the program at 6. The cost is $20 for non-members; $8 for members, and $7 for students (with valid ID). Registration is available through the website, http://www.commonwealthclub.org/ or by telephoning (415) 597-6705.
Non-club-members can enjoy the program at the discounted rate of $8 (rather than $20), using the coupon code listed below:
Thursday, Jan. 30, 6 p.m. - Scott Carroll: Conciliation Biology: An Approach to Conservation that Reconciles Past, Present and Future Landscapes in Nature. Coupon Code: friendsforcarroll. For program detail and registration, please see: http://www.commonwealthclub.org/events/2014-01-30/scott-carroll-conciliation-biology
Carroll, who directs the Institute for Contemporary Evolution, does research on patterns of ongoing evolution in wild and anthropogenic environments. His studies on evolutionary changes in soapberry bugs in response to plant introductions are seminal contributions to our understanding of diversification.
The UC Davis evolutionary ecologist is the co-editor of the book, Conservation Biology: Evolution in Action (Oxford University Press, 2008). with Charles Fox, professor of insect genetics, behavior and evolutionary ecology, University of Kentucky.
Carroll co-authored a research paper that was selected in 2013 as one of the top 100 most influential papers ever published by the worldwide British Ecological Society, headquartered in London. The 13-page article, “Adaptive Versus Non-Adaptive Phenotypic Plasticity and the Potential for Contemporary Adaptation in New Environments,” is published in the April 2007 (Volume 21) in the British Ecological Society’s journal, Functional Ecology.
The Commonwealth Club of California is the nation's oldest and largest public affairs forum. It brings more than 400 annual events on topics ranging across politics, culture, society and the economy to 20,000 members. Its mission: to be the leading national forum open to all for the impartial discussion of public issues important to the membership, community and nation.
Founded in 1903, The Commonwealth Club has played host to a diverse and distinctive array of speakers, from Teddy Roosevelt in 1911 to House Speaker Nancy Pelosi, California Governor Arnold Schwarzenegger, actor Alec Baldwin and author Christopher Hitchens in recent years. Martin Luther King, Jr., Ronald Reagan, Bill Clinton and Bill Gates have all given landmark speeches at The Club.
For members outside the Bay Area, the Club's weekly radio broadcast — the oldest in the U.S., dating back to 1924 — is carried across the nation on public and commercial radio stations. The website archive features audio and video of our recent programs, as well as selected speeches from our long and distinguished history.
Two More UC Speakers Pending
Talks by two more UC scientists, butterfly expert Arthur Shapiro of the UC Davis Department of Evolution and Ecology and forest ecologist Joe McBride of UC Berkeley, are pending at the Commonwealth Club.
Shapiro will speak on "Ecological Communities and the March of Time" at noon, Monday, March 24, while McBride will discuss "The History, Ecology and Future of Eucalyptus Plantations in the Bay Area at noon Wednesday, April 9.
That they're Public Enemy No. 1?
According to a recent Nature journal essay, non-natives are so vilified today that a “pervasive bias” exists against non-native species, a bias embraced by “the public, conservationists, and managers and policy-makers, as well by as many scientists, throughout the world.”
The native-vs.-non-native species distinction appears to be the “guiding principle” in today’s conservation and restoration management, say 19 ecologists in their essay, “Don’t Judge Species on Their Origins.”
Mark Davis, a biology professor at Macalester College, St. Paul, Minn., is the lead author. The other co-authors include Scott Carroll of UC Davis.
Carroll, an ecologist in professor Sharon Lawler’s lab, and the founding director of the Davis-based Institute for Contemporary Evolution, contributed his work on conciliation biology to the thought-provoking essay. He holds a doctorate in biology from the University of Utah.
“Global change alters conditions for all species, and from a practical perspective, origin can be only one of many criteria we consider,” Carroll told us. “Appraising non-native organisms more openly invites us to more seriously contemplate our aims when managing novel communities of mixed origin.”
Carroll is often out chasing soapberry bugs (a key research interest), writing research papers and delivering presentations. He considers soapberry bugs "wondrous examples of evolution happening right now--as we change the world, these beautiful insects are quickly adapting, and in the process directly revealing how evolution works."
You can't miss his presence. At 6 foot-10 inches, he towers over his colleagues.
And the soapberry bugs!
Department of Entomology website
Conciliation Biology: the Eco-Evolutionary Management of Permanently Invaded Biotic Systems by Scott Carroll, published in 2011 in Evolutionary Applications.
Soapberry Bugs of the World Website (Scott Carroll)
Scott Carroll Website
Scott Carroll: Curriculum Vitae
That would be "the rapidly evolving soapberry bugs."
Hugh Dingle, emeritus professor of entomology at UC Davis, will present a UC Davis Department of Entomology seminar from 12:10 to 1 p.m. on Wednesday, Nov. 10 in 122 Briggs Hall.
His topic: "And the Beak Shall Inherit: Contemporary Local and Reverse Evolution in Morphology and Life History in American and Australian Soapberry Bugs."
Professor Sharon Lawler of the Department of Entomology faculty will introduce him.
During his 20-year tenure on the UC Davis faculty, Dingle studied various aspects of insect migration “and especially the relation between migration and the evolution of life histories.”
“One aspect of these studies,” he said, “was the rapid contemporary evolution of insects (soapberry bugs) on introduced host plants (golden rain trees), including the interesting genetic relationships between feeding habits and variation in the ability to fly and migrate.”
His seminar will focus on laboratory-selection experiments on North American soapberry bugs designed to assess the genetic relationships among rapidly evolving traits, including the feeding apparatus and the structure and function of wings and wing muscles, necessary to migratory behavior.
“The bugs respond rapidly to selection for both forward and reverse evolution, demonstrating that the genetic variation necessary for evolution is present in the bugs even after intense natural selection,” Dingle said.
Of particular interest is a genetic correlation between mouthpart structure and wing morph frequency so the two traits share genes and evolve together. “The ecology of the bugs reveals why this might be the case,” he said. “A similar rapidly evolving soapberry bug system exists in Australia allowing intercontinental comparisons of contemporary evolution in these bugs as a consequence of the introduction of exotic host plants.”
For the last seven years, Dingle has been living and doing research at the University of Queensland, Brisbane, Australia. Now a resident of Davis, he is continuing his research from his headquarters in the Lawler lab.
Dingle received his bachelor's degree in zoology, with honors, from Cornell University, and his master's and doctorate degrees in zoology from the University of Michigan.
Meanwhile, be sure to check out UC Davis researcher Scott Carroll's website on soapberry bugs. Carroll, also associated with the Lawler lab, maintains a Flickr site and invites images of soapberry bugs.
Evolution in action...