Georgetown College. Georgetown University.

Dr. Wimp's work in community genetics focuses on arthropod diversity. (Photo: Roland Dimaya)

By Megan Weintraub

In nature, appearances can be deceiving. A forest full of trees may all look identical to one another, but the animals that depend on the trees for survival perceive hidden differences between them. This variation determines whether or not a plant-feeding animal, or herbivore, will find the tree to be appetizing or disgusting. As a result, the choices made by the herbivores will affect the behavior of the predators that feed on the herbivores, as they will seek out the trees where their prey are likely to be found.

“Thus, genetic variation in the trees builds layers of community structure,” explains Dr. Gina Wimp. “Different tree genotypes have their own unique animal associates.”

Community genetics, a field of biology championed by Dr. Wimp, looks at the effects of genetic variation that extend beyond one species to affect other organisms and biodiversity. The field provides a theoretical underpinning for many current conservation projects across the country. Scientists in this field seek to forge a link between the subdisciplines within biology of landscape community ecology and evolutionary genetics.

By linking observations and quantified data, scientists can develop theories about what they study in the field. In turn, these theories lend scientists credibility when they make policy recommendations about the best ways to restore habitats.

Dr. Wimp’s research predominantly involves arthropods, or “insects and their related friends.” This large category of invertebrates includes a wide variety of insects, spiders, and mites. From her observations in the field, Dr. Wimp noticed that the types of arthropod communities varied within one species of cottonwood tree around the Weber River Forest in Utah. She wondered if the arthropods were selecting a particular cottonwood tree habitat because of its genotypic properties. To test her findings, she used common garden experiments and linked these findings with stands of trees growing in the wild to see if she could find differences in the arthropod community based on the different genotypes of cottonwoods.

“What we found was astonishing,” recalls Dr. Wimp. “Almost 60 percent of arthropod diversity could be explained by the cottonwood genetic diversity. In other words, each type of tree draws in or repels certain arthropod communities, and we were able to predict those relationships. Insects were picking and choosing their favorites based on the tree’s genotype.”

Dr. Wimp and her colleagues then scaled up their findings to larger regions and found that the rules held true. As a result, they have advised conservation groups, such as the Utah Division of Wildlife and the Bureau of Reclamation, to plant genetically diverse stocks in order to produce a difference in susceptibility among individual plants which can help an ecosystem withstand attack from pests and disease, and variability in weather brought about by climate change. She will continue her research with new seedlings that will be planted at the Blandy Experimental Farm at the University of Virginia.

“I think we’ve helped to bridge the divide between ecologists and the people making policy decisions,” says Dr. Wimp. “We have a lot to learn from each other, and I think our combined efforts can go a long way to restore our country’s habitats.”

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