Tag Archive for Singer

NSF Supports Singer’s Research on Habitat Fragmentation in Connecticut

Mike Singer.

Mike Singer.

Mike Singer, professor of biology, professor of environmental studies, received a three-year grant from the National Science Foundation this month to support a study on habitat fragmentation. Fragmentation occurs when contiguous habitats become separated into smaller, isolated areas often caused by human activities (new roads, housing developments) or natural processes (flooding, drought).

Singer and his colleagues will study the effect of anthropogenic forest fragmentation on the food web of plants, herbivores, and carnivores (tri-trophic interactions) in Connecticut. The project will focus on relationships among deer, trees, caterpillars, and songbirds.

The grant, which will be awarded over three years, is shared with Robert Bagchi, David Wagner, and Christopher Elphick in the University of Connecticut’s Department of Ecology and Evolutionary Biology. Wesleyan’s part of the award totals $258,933 and UConn’s part totals approximately $573,000.

As part of the grant, Singer will recruit a new PhD student to work on the study.

The research team will test several possible reasons for the loss of caterpillars, which are important food for songbirds, in highly fragmented forests. For example, some of their preliminary evidence suggests that forest fragmentation creates better habitat for deer, which browse out some of the best food plant species for caterpillars.

The PhD student will be tasked with testing the hypothesis that caterpillars grow more poorly on the plants in highly fragmented versus large forest tracts.

At Wesleyan, Singer teaches courses on conservation biology, ecology, plant-animal interactions and evolutionary biology.

Biology PhD Student Bernardo Finds Parasitoids Alter Diets of Hosts

Parasitoid wasp larvae emerging from the carcass of a caterpillar host. (Photo by Melissa Bernardo)

Parasitoid wasp larvae emerging from the carcass of a caterpillar host. (Photo by Melissa Bernardo)

“As far as relationships go, parasitism may seem particularly selfish: one partner benefits at the expense of another. Many parasites even alter the behavior of their hosts to get what they need. Parasitoids are similar, but they usually spend a significant portion of their lives living inside or on their hosts’ bodies and controlling them from the inside-out, before ultimately killing and often consuming them.”

So begins an article in Science Daily featuring research by Melissa Bernardo, a PhD student in biology working with Michael Singer, associate professor of biology, associate professor of environmental studies. Bernardo has been studying how parasites and parasitoids influence feeding behavior of their hosts. Many scientists believe diet manipulation “could be reasonable because the parasite might need different types of nutrients than the host,” according to the article. But this phenomenon has been studied little in the past, and hasn’t been shown conclusively.

In a series of experiments, Bernardo found that when wooly bear caterpillars were allowed to choose between a protein- or carbohydrate-rich diet, those who were unparasitized chose a protein diet, while those parasitized by a type of wasp preferred a carbohydrate diet. In effect, Bernardo said, “The wasps are making their hosts carb-load.”

The article continues

Physics, Biology, Chemistry, Astronomy Departments Teach Fifth Graders About Science

Fifth graders from Snow Elementary School in Middletown toured Wesleyan’s astronomy, biology, chemistry, and physics departments on June 8.

Brian Northrop, assistant professor of chemistry, and Snow School students watch chemistry in action during their visit to Wesleyan. This annual program allows local fifth graders to see how science can be exciting as well as educational.

Brian Northrop, assistant professor of chemistry, and Snow School students watch chemistry in action during their visit to Wesleyan. This annual program allows local fifth graders to see how science can be exciting as well as educational.

Singer’s Caterpillar Defense Studies Published in Ecology, Entomology Journals

In a recent study, Associate Professor Mike Singer compared 41 caterpillar species to show the link between dietary breadth and vulnerability to predators.

Mike Singer

Mike Singer, associate professor of biology, associate professor of environmental studies, is the co-author of several recently-published papers. They include:

Thee struggle for safety: effectiveness of caterpillar defenses against bird predation,” is in press and will appear in the April 2015 issue of Oikos. This article shows how the camouflaged or bold appearance of a caterpillar can protect it from predatory birds in Connecticut forests. Former BA/MA student, Isaac Lichter-Marck ’11, ’12, is the first author of this article.

Defensive mixology: Combining acquired chemicals toward defense,” is published in Functional Ecology, 2015. This article proposes a conceptual framework to study the use of natural drug cocktails by animals and plants. Peri Mason Ph.D. ’12 is the first author of this article.

The global distribution of diet breadth in insect herbivores,” is published in the Proceedings of the National Academy of Sciences USA, 2015. This article reports a common mathematical distribution that describes the range of dietary specificity of plant-feeding insects around the world. This research is an international collaboration among many ecologists.

Ecological immunology mediated by diet in herbivorous insects,” published in Integrative and Comparative Biology 54, pages 913-921, 2015. This article proposes a conceptual framework to study how diet influences the immune system in plant-feeding insects, such as caterpillars. Peri Mason Ph.D. ’12 co-authored this article.

Enemy-free space for parasitoids,” published in Environmental Entomology 43, pages 1,465-74, 2014. This article uses three case studies to argue that parasitic insects show a signature of adaptation to predation pressure, which has been an overlooked agent of evolution for parasites.

And “A mixed diet of toxic plants enables increased feeding and anti-predator defense by an insect herbivore,” published in Oecologia 176, pages 477-486, 2014. This article shows evidence that woolly bear caterpillars benefit in two ways from a diet that includes multiple toxic plant species. First, the caterpillars eat more food overall so they grow larger. Second, they become more deterrent to their predators. Peri Mason Ph.D. ’12 is the first author of this article.

Singer’s Study Reveals that Finicky Feeders Avoid Bird Predation

In a recent study, Associate Professor Mike Singer compared 41 caterpillar species to show the link between dietary breadth and vulnerability to predators.

In a recent study, Associate Professor Mike Singer compared 41 caterpillar species to show the link between dietary breadth and vulnerability to predators.

Grandmothers used to warn youngsters against being “a jack of all trades, and a master of none,” and with good reason, at least in the animal kingdom, according to research by Mike Singer, associate professor of biology, associate professor of environmental studies.

Singer’s decade of research in the ecosystems of Connecticut forests reveals that caterpillars with finicky feeding habits avoid predation from birds, whereas those that feed generally on many plants become meals for baby birds. The “specialist” bugs are much better at survival.

Singer and five collaborators published these findings in the prestigious Proceedings of the National Academy of Sciences June 16.

Mike Singer studies the Papilio glaucus, one of the most bird-resistant caterpillars. (Photo by Mike Singer)

Mike Singer studies the Papilio glaucus, one of the most bird-resistant caterpillars. (Photo by Mike Singer)

“Dietary specialization of herbivores drives the dynamics of this food chain,” Singer explained. Caterpillars with generalized diets are less likely than specialists to be camouflaged or to display warning colors or features to avian predators.

A familiar example of a dietary specialist is the caterpillar of the Monarch butterfly, which feeds exclusively on milkweed plants. This caterpillar accumulates toxins from its food-plants, rendering it unpalatable to birds and other predators. The toxic caterpillar is distinctively striped and colored as a warning to its enemies.

Singer, Farkas, Skorik Published in American Naturalist

Mike Singer, associate professor of biology; Tim Farkas ’08, MA ’10 and Christian Skorik ’09, MA ’10 are the authors of “Tritrophic Interactions at a Community Level: Effects of Host Plant Species Quality on Bird Predation of Caterpillars,” published in the March issue of The American Naturalist. Researchers at the University of California at Irvine also contributed to the report.

Researchers report that a tree is not a tree is not a tree when it comes to birds foraging for tree-feeding caterpillars. With help from a small army of students, the scientists ran a field experiment in Connecticut forests over two years, involving hundreds of tree branches either bagged with garden variety, bird-proof netting or left open to foraging birds. They found that disparities in caterpillar growth between different tree species, such as black cherry and American beech, changed a caterpillar’s risk of becoming bird food. On balance, nutritious trees like black cherry can increase a caterpillar’s risk of being taken by foraging birds by 90%. This neat pest-control system works because the most nutritious tree species harbor the greatest numbers of caterpillars, offering up the easiest pickings for birds. For tree-feeding caterpillars, however, no tree is completely safe. Even without the risk of being in a crowd, nutritionally poor trees like American beech can slow down a caterpillar’s growth and prolong its exposure to bird predation.

Read more about the study in this past Wesleyan Connection article.

Birds Seek Caterpillars on Nutritious Trees, Says Biology Researchers

Christian Skorik photographed this black-capped chickadee munching on a caterpillar during his group's study.

A word of caution to the caterpillar munching on that delicious, nutritious black cherry tree: watch out for hungry birds.

Michael Singer, associate professor of biology, is the lead author of a new study published in The American Naturalist on the effect of a caterpillar’s choice of feeding spot on its chances of becoming bird food. The article found that on balance, nutritious trees, like black cherry, can increase by 90 percent a caterpillar’s risk of being taken by foraging birds. According to the article, this effect is seen because the most nutritious tree species harbor the greatest number of caterpillars, offering up the easiest pickings for birds. Unfortunately for caterpillars, feeding on less crowded, nutritionally poor trees, like American beech, also carries risk by slowing down a caterpillar’s growth and prolonging its exposure to bird predation.

The article was co-authored by two former Wesleyan students—Tim Farkas ’08, MA ’10 and Christian Skorik ’09, MA ’10—and researchers at the University of California at Irvine. Numerous undergraduates in the Hughes summer research program assisted with the field experiment in Connecticut forests over a period of two years.

NSF Supports Singer’s, Mason’s Herbivore Defense Research

Michael Singer, associate professor of biology, associate professor of environmental studies, received a $10,000 Doctoral Dissertation Improvement Grant from the National Science Foundation for  “The Role of Toxin Complementation in Herbivore Defense.” The award will support graduate student Peri Mason’s doctoral dissertation.

Several Faculty Receive Promotions, Tenure

Wesleyan has announced the following promotions of faculty, effective July 1, 2010:

Promotion with Tenure

During the academic year, the Wesleyan Board of Trustees maintains an ongoing process of tenure case consideration. During its most recent review, the Board awarded tenure to one faculty member effective July 1, 2010.

Michael Singer, associate professor of biology, was appointed assistant professor at Wesleyan in 2004. Previously he was postdoctoral fellow at the University of Arizona’s Center for Insect Science, in Tucson.

Singer’s research examines the evolutionary ecology of tri-trophic interactions between plants, herbivores and carnivores. In considering

Singer Published in Annals of the Entomological Society

Michael Singer, associate professor of biology, associate professor of environmental studies, is the co-author of “Triptrophic effects of host plants on an herbivore-pathogen interaction,” published in the Annals of the Entomological Society of America, 2010.