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Bay Area students and university researchers find climate indicator in beetles

SANTA CLARA, Calif, Sept. 12, 2000 - Biology professors at Santa Clara University and Sonoma State University announced they have discovered an enzyme in beetles that appears to act as an indicator of changes in local air temperature.

The findings by the two scientists, Elizabeth Dahlhoff (Santa Clara) and Nathan Rank (Sonoma State), were reported in an article titled, "Functional and physiological consequences of genetic variation at phosphoglucose isomerase (eye SOM er aze): heat shock protein expression is related to enzyme genotype in a montane beetle," published in the current issue of The Proceedings of the National Academy of Sciences, USA.

This university research, scientists say, provides new insights into: 1) how insects such as beetles adapt to environmental temperatures; and 2) how the presence of specific forms of a protein in these beetles' body chemistry may be measured as an indicator of climate changes, such as global warming.

This research focused on the willow beetle Chrysomela aeneicollis, a spotted little bug that lives in isolated mountain drainages in the Sierra Nevada. The results suggest that California populations of these beetles are locally adapted to temperature.

This link supports the hypothesis that because beetles are adapted to local temperature, they may be an excellent indicator species for examining the effects of global climate change on native organisms in alpine environments, the scientists said.

Ongoing research on this possibility is supported by the National Science Foundation and is being conducted with undergraduate students at Santa Clara University and Sonoma State University.

Beetles from warmer drainages possess a different form of the enzyme phosphoglucose isomerase (PGI) than those from cooler drainages, the scientists concluded. During the cool rainy period in the early 1990s, the "cool-adapted" form of the enzyme increased in frequency in beetle populations.

In the laboratory, the researchers found a temperature-dependent pattern of enzyme function that is consistent with the hypothesis of temperature adaptation. They also found a link between the form of PGI that a beetle possesses, and its production of specialized heat-shock proteins (proteins induced by heat stress).

Santa Clara University is private Catholic, Jesuit university located in Santa Clara, with 4,400 undergraduate and 3,300 graduate students. Dahlhoff is an assistant professor of biology at SCU.

Sonoma State University, located in Rohnert Park, is part of the public California State University system. Both universities involve undergraduate students in scientific research projects.


For additional information or to arrange interviews, contact Barry Holtzclaw at Santa Clara University, 408-554-5162,, or Susan Kashack at Sonoma State University, 707-664-2122, Photo of the beetle is available in jpeg format, attached. To see a text of the research article, see

Tags: beetles

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