University of Michigan
Department of Ecology and Evolutionary Biology

A research team led by Professor Barry OConnor and Dr. Pavel Klimov has used a large-scale genetic study of the house dust mite to uncover an example of reversible evolution that appears to violate a deeply rooted supposition that evolution is unidirectional and irreversible, dubbed Dollo's law.

But this "law" is not universally accepted and is the topic of heated debate among biologists. The study shows that tiny free-living house dust mites, which thrive in the mattresses, sofas and carpets of all homes, evolved from parasites, which in turn evolved from free-living organisms millions of years ago.

"All our analyses conclusively demonstrated that house dust mites have abandoned a parasitic lifestyle, secondarily becoming free-living, and then speciated in several habitats, including human habitations," according to Klimov, first author and an EEB research scientist and OConnor.

Their paper, "Is permanent parasitism reversible?--Critical evidence from early evolution of house dust mites," was published online March 8, 2013 in the journal Systematic Biology.

The story has been widely covered in the media including this Discover magazine blog article, The New York Times Science section, and in Newsweek/The Daily Beast.

U-M News Service press release

Watch for an EEB research feature coming soon

Caption: A scanning electron microscope image of an American house dust mite. Image credit: G. Bauchan and R. Ochoa.

The Michigan Botanical Club’s peer-reviewed quarterly journal The Michigan Botanist has dedicated its current issue to Ed Voss, the former U-M professor emeritus of ecology and evolutionary biology and curator emeritus of vascular plants at the U-M Herbarium, who died February 13, 2012.

Voss’s focus was on the vascular plants of the Great Lakes region and his contributions were legendary. In addition to his career at U-M, he was a long-time instructor at U-M Biological Station, he founded The Michigan Botanist and served in an editorial capacity for 15 years for the journal and many other publications. His most noted accomplishment was the three volume set of Michigan Flora which is still considered “the source” for flora in Michigan and the Great Lakes region.

Read the tribute issue (Volume 51) to Voss of The Michigan Botanist with articles by Dr. Tony Reznicek, Herbarium curator, research scientist and assistant director, and Dr. Richard Rabeler, research scientist and collection manager, Professor Emeritus Brian Hazlett, and Mike Penskar, visiting assistant research scientist, and many others who worked with Voss extensively over the years.

Read more in previous EEB web news

Caption: Ed Voss with his Aquatic Flowering Plants class in 1965. Credit: John Russell.

Sea surface temperatures in the tropical South Atlantic Ocean can be used to accurately forecast, by up to four months, malaria epidemics thousands of miles away in northwestern India, a U-M theoretical ecologist and her colleagues have found.

Colder-than-normal July sea surface temperatures in the tropical South Atlantic are linked to both increased monsoon rainfall and malaria epidemics in the arid and semi-arid regions of northwest India, including the vast Thar desert, according to Professor Mercedes Pascual and her colleagues, who summarize their findings in a paper published online March 3, 2013 in the journal Nature Climate Change.

Previous efforts to forecast malaria outbreaks in northwest India have focused largely on monsoon-season rainfall totals as a predictor of the availability of breeding sites for the Anopheles mosquitoes that transmit the disease. That approach provides about a month of lead time before outbreaks occur.

The new forecasting tool should improve public health in the region by increasing warning time, thereby informing decisions about treatment preparedness and other disease-prevention strategies, said Pascual, the Rosemary Grant Collegiate Professor of Ecology and Evolutionary Biology and a Howard Hughes Medical Institute investigator. Planning for indoor insecticide spraying, one widely used control measure, could benefit from the additional lead time, for example.

"The climate link we have uncovered can be used as an indicator of malaria risk," Pascual said. "On the practical side, we hope these findings can be used as part of an early warning system."

Andres Baeza a U-M EEB graduate student was one of Pascual's co-authors on the Nature Climate Change paper.

The paper is being covered extensively in the media, including these articles: Livemint and The Wall Street Journal and The Times of India. Malaria and the Indian monsoon is the featured story on the nature climate change website.

U-M News Service press release

Captions: (top) A female Anopheles stephensi mosquito, which transmits malaria in western India. Credit: Kedar Bhide.(bottom) Mercedes Pascual, Andres Baeza.

U-M researchers have demonstrated for the first time that stress hormones are responsible for altering the body shape of developing animals, so they are better equipped to survive predator attacks.

Through a series of experiments conducted at field sites and in the laboratory,  researchers demonstrated that prolonged exposure to a stress hormone enabled tadpoles to increase the size of their tails, which improved their ability to avoid lethal predator attacks by swimming away faster.

“This is the first clear demonstration that a stress hormone produced by the animal can actually cause a morphological change, a change in body shape that improves their survival in the presence of lethal predators. It's a survival response," said Professor Bob Denver.

First author of the paper is Jessica Middlemis Maher, a recent EEB doctoral graduate who is now at Michigan State University, with coauthors Professors Denver and Earl Werner. The team's surprising findings are detailed in a paper published online March 5, 2013 in the journal Proceedings of the Royal Society B. Middlemis Maher conducted the work for her dissertation. Werner is director of the E.S. George Reserve in Pinckney, Mich., northwest of Ann Arbor where tadpoles were collected from ponds.

The paper is being widely covered in the media, including this Los Angeles Times article and in the Spanish language media.

U-M News Service press release

Watch for an EEB research feature coming soon.

Captions: (top) A wood frog tadpole with a normal size tail. (bottom)  In response to prolonged exposure to the threat of predator attacks, this wood frog tadpole increased the height of its tail, which makes it better equipped to survive such attacks. Image credit: Michael Benard

EEB graduate student Na Wei has been awarded the Barbour Scholarship for 2013-14 by the Rackham Graduate School.

Wei joins a long line of outstanding women who, over the past 98 years, have become leaders in science, education, public service, medicine and other fields in their home countries all over the world. She will receive $18,000, tuition and health and dental insurance for the academic year. Her advisor is Professor Christopher Dick.

Wei’s dissertation research focuses on seed- and pollen-mediated gene flow in tropical trees. “Seed and pollen dispersal are the most important phases of plant life cycles because they successfully move genomic materials over time and space,” Wei explained. “Up until now, our knowledge of the relative importance of seed- and pollen-mediated gene flow in trees has been biased toward temperate zone species. With primarily wind-pollinated and -dispersed temperate zone trees, pollen flow is recognized as the principle avenue of gene transport. Yet, it remains unclear whether this generalization for northern species can be extrapolated to tropical moist forest trees where animals are the primary pollinators and seed dispersers.

“My research seeks to evaluate this generality of pollen-dominated gene flow in tropical trees by unambiguously decomposing the seed and pollen component from the overall gene flow in a suite of dioecious (distinctly male and female) trees of different dispersal and pollination syndromes growing in the mature forests of Barro Colorado Island, Panama.

“With spatially explicit pathways of seed and pollen movement, this research will be able to quantify the relative magnitude of seed and pollen dispersal in this set of distantly related tropical tree species, and will improve our understanding of the respective ecological and evolutionary importance of seed and pollen dispersal in relatively under-studied tropical forests. It provides a solid empirical framework for latitudinal comparisons between tropical trees and temperate zone trees, as well as comparisons between tree species of different life history characteristics."

Wei is originally from China. She graduated from Nanjing University with a master's degree in ecology.

In 1914, the bequest of Levi L. Barbour established a scholarship program at U-M for women of the highest academic and professional caliber from the area formerly known as the Orient (encompassing the region extending from Turkey in the west to Japan and the Philippines in the east) to study modern science, medicine, mathematics and other academic disciplines and professions critical to the development of their native lands.

Caption: (top photo) Na Wei in the 50 hectare Forest Dynamics Plot on Barro Colorado Island, Panama, where she did her field work, standing near an enormous tree, Ceibs pentandra.

Are you interested in helping to turn high school students on to science? EEB graduate student Katherine Crocker is looking for participants for a local science education outreach project.

Science teachers at Ann Arbor’s Huron High School are really interested in having graduate students, postdoctoral fellows, and faculty give guest talks to show students the relevance of science outside the classroom. They're looking for 20 - 40 minute, high-school level talks relating your research to class material.Their secondary interest is in lab tours.

If you're interested (in giving talks, helping coordinate lab tours, or helping to record talks for digital access), please fill in this short survey (less than two minutes). Crocker will compile the information in a spreadsheet for the HHS science teachers, who may contact you. If you're concerned about time commitment, you can partner with others whose research relates to yours so that you can participate at a level convenient to you (either splitting the sections or recording your talk).

“This is a great opportunity to practice talking about your research, and to do science outreach!” said Crocker.  Please pass the information along to anyone else who might be interested.

Jingchun Li, an EEB graduate student in the lab of Professor Diarmaid Ó Foighil, has been awarded a Rackham Predoctoral Fellowship. The fellowship supports outstanding doctoral students who have achieved candidacy and are actively working on dissertation research and writing.

 “The enormous biodiversity on earth not only provides humans valuable biological resources, but also serves as a crucial component of our highly interdependent ecosystem. How this great biodiversity is generated remains a central question of biology and my thesis research aims to help answer it,” begins Li’s personal statement for the fellowship.

Li’s research is one of the first empirical investigations of how abiotic and biotic factors affect the evolutionary diversification of a major marine lineage, the bivalve superfamily Galeommatoidea. She is inspired by the increasing realization among macroevolutionary biologists that biotic interactions cannot be ignored if theory is to be reconciled with natural systems and that the interplay of abiotic and biotic drivers has shaped biotas through time.

The role of biotic factors in driving species diversification has been extensively studied in terrestrial systems. Unfortunately, their impact on marine life is much less understood, even though 71 percent of the earth’s surface is covered by the ocean.

“I address this deficiency by studying the evolution of the hyperdiverse clam group Galeommatoidea. It is a particularly apt group because it contains large numbers of obligate commensal as well as free-living species and is therefore amenable to comparative approaches.

Li tackles the issue on three levels: 1) on a global level, for the entire superfamily; 2) on a regional level, for a faunal assemblage of commensal and free-living taxa that span three well-defined biogeographic provinces in southern Australia; 3) on a microevolutionary level, focusing on commensal species with multiple hosts.

Construction of global molecular phylogenies allows Li to test if free-living and commensal ecologies have differentially impacted rates of lineage diversification and morphological evolution in this group. The regional phylogeographic analyses engage with endemic diversification among free-living and commensal lineages along a contiguous coastline containing multiple abiotic breakpoints. This will yield a high-resolution analysis of how abiotic and biotic factors interact to shape marine diversification. The microevolutionary approach directly examines the importance of host-shifts in promoting speciation of commensal species.

Li will receive $28,800 over three terms, candidacy tuition and registration fees for fall and winter as well as GradCare health and dental insurance coverage for 2013-14. An award reception is planned for early April. Congratulations!

Read previous EEB web news on Li’s research

Caption: Jingchun Li with classmates on a boat trip at the University of Washington's Friday Harbor Laboratories on San Juan Island, near Seattle. They were collecting marine invertebrates as part of a marine invertebrate class.

Mark Hunter, Henry A. Gleason Collegiate Professor of Ecology and Evolutionary Biology is the 2013 recipient of the Rackham Master’s Mentoring Award.

Hunter was nominated “for his dedicated and highly successful work as the founding director of the Frontiers Master’s Program,” according to EEB Professor and Chair Deborah Goldberg.

Following are some quotes from current and graduated Frontiers students:

“In Mark, we can always find support and words of encouragement, especially in moments when we doubted ourselves or our capabilities. He is always there to listen and believe in us.” (current second year Frontiers student)

“He was one of the most supportive and encouraging advisors I have ever known.” (2012 Frontiers graduate, now first year Ph.D. student at University of California at Berkeley)

“He is, all at once, very intense and intelligent, but also understanding and compassionate. It is these qualities, all wrapped up perfectly into one person, that have given me the confidence to know that I am good enough; good enough not just for the program that I am in, but good enough for anything that I try to do. He has supported my every endeavor, with words of wisdom, personal connections, and recommendation letters, and I don't think that I could have asked for a better advocate for my success than him.” (current second year Frontiers student)

Goldberg continued, “Another way to look at Mark’s success as a mentor of master’s students is to look at the overall success of the students in the Frontiers program while he was director.”  Among the three cohorts (12 students) he’s overseen so far, 10 have completed the program with a master’s degree and two from the most recent cohort are still working on their degrees. Ten students are currently in Ph.D. programs, including at U-M EEB (four students), Harvard University, UC Berkeley, UCLA, Wayne State University, Michigan State University, and University of Minnesota.

“Finally, Mark’s stellar role running the Frontiers program in EEB led Rackham to use it as a model in developing a successful proposal to NSF’s bridges to the baccalaureate program to expand the model to several other STEM departments in LSA.

 “Mark has been a brilliant mentor to individual master's students, but even more important, he has influenced the very way we educate master's students both in EEB and across multiple departments through his work in the Rackham bridging programs,” said Goldberg.

"The award came as a complete surprise,” said Hunter. “Really, the credit belongs to Deborah (Goldberg), Beverly (Rathcke) and John (Vandermeer) who conceived the idea (of the Frontiers Master’s Program) in the first place, and to Abby Stewart and Janet Weis who were so supportive as the program developed. Add to that the wonderfully talented cohorts of Frontiers students and the support of U-M Biological Station for our summer program, and I was just lucky to be involved."

The Rackham Graduate School has developed a number of initiatives and programs designed to improve the resources available to faculty mentors and their students, and really encourage a culture of mentorship at U-M. One of the ways they recognize the importance of mentoring is with three annual faculty awards for outstanding mentorship, this is one of those awards.

Running cockroaches start to recover from being shoved sideways before their dawdling nervous system kicks in to tell their legs what to do, researchers have found. These new insights on how biological systems stabilize could one day help engineers design steadier robots and improve doctors' understanding of human gait abnormalities.

In experiments, the roaches were able to maintain their footing mechanically – using their momentum and the spring-like architecture of their legs, rather than neurologically, relying on impulses sent from their central nervous system to their muscles.

"The response time we observed is more than three times longer than you'd expect," said Shai Revzen, a U-M assistant professor of electrical engineering and computer science, as well as ecology and evolutionary biology. Revzen is the lead author of a paper on the findings published online in Biological Cybernetics. It will appear in a forthcoming print edition.

To gather detailed information about the roaches' gait, the researchers utilized a technique Revzen developed several years ago called kinematic phase analysis. It involves using a high-speed camera to constantly measure the position of each of the insects' six feet as well as the ends of its body. A computer program then merges the continuous data from all these points into an accurate estimate of where the roach is in its gait cycle at all times. The approach gives scientists a more detailed picture than measuring the timing of footfalls – a common metric used today to study gait.

In kinematic phase analysis, the signals are converted into a wave graph that illustrates the insect's movement pattern. The pattern only changes when the nervous system kicks in. How do the researchers know this? In a separate but similar experiment, they implanted electrodes into the legs of seven cockroaches to measure nerve signals.

Robot makers often look to nature for inspiration. As animals move through the world, they have to respond to unexpected disturbances like rocky, uneven ground or damaged limbs. Revzen and his team believe that patterns in how they move as they adjust could give away how their machinery and neurology work together.

"The fundamental question is, 'What can you do with a mechanical suspension versus one that requires electronic feedback?" Revzen said. "The animals obviously have much better mechanical designs than anything we know how to build. But if we could learn how they do it, we might be able to reproduce it."

More than 70 percent of Earth's land surface isn't navigable by wheeled or tracked vehicles, so legged robots could potentially bridge the gap for ground-based operations like search and rescue and defense.

For human gait analysis, Revzen and colleagues said their noninvasive, high-resolution kinematic phase approach could be valuable in the biomedical community.

"Falls are a primary cause for deterioration in the elderly," Revzen said. "Anything we can do to understand gait pathology and stabilization of gait is very valuable."

These experiments were funded by the National Science Foundation and conducted at the University of California, Berkeley, before Revzen came to U-M. Shortly before Revzen joined U-M, he received a Young Investigator Award from the Army Research Office for related research.

U-M News Service press release and video

Increasing evidence suggests that loss of Earth’s biological diversity will compromise our planet’s ability to provide the goods and services societies need to prosper.

Read the opinion piece in The Scientist (Feb. 20, 2013) by Brad Cardinale, an associate professor in the Department of Ecology and Evolutionary Biology and in the School of Natural Resources and Environment. He is director of the school's Conservation Ecology Program and teaches courses in conservation, restoration ecology, and ecosystem services. He is also an elected member of the International Council for Science's research program DIVERSITAS.

The article ends, “We are taking the very genes and species that have made Earth an inhabitable and biologically productive planet over the past 3.8 billion years, and we are lining them up on the edge of a cliff from which there is no return. If the ever growing human population is to continue to prosper, we must better appreciate how our own well-being is directly linked to the great variety of life that is the most striking feature of our planet.”