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Bay Area Researchers Find Climate Indicator In Beetles

Sonoma State University Biology Professor Nathan Rank and Santa Clara University Biology Professor Elizabeth Dahlhoff have discovered an enzyme in beetles that appears to act as an indicator of local air temperature.

Their research article, "Functional and physiological consequences of genetic variation at phosphoglucose isomerase: heat shock protein expression is related to enzyme genotype in a montane beetle," has been published in the current issue of The Proceedings of the National Academy of Sciences, USA. This research provides new insights into two issues: 1) how insects such as beetles adapt to environmental temperatures in which they live; and 2) how the presence of specific forms of a protein contained by these beetles may be used as an indicator of climate change.

This research focused on in the willow beetle Chrysomela aeneicollis living in isolated mountain drainages in the Sierra Nevada (California). The results suggest that California populations of these beetles are locally adapted to temperature. Beetles from warmer drainages possess a different form of the enzyme phosphoglucose isomerase (PGI) than those from cooler drainages. 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). This link further supports the hypothesis that beetles are adapted to local temperature. This adaptation could result in striking consequences (i.e. local extinction of certain genetic types) for native populations of beetles during periods of climate warming.
As a result of their temperature adaptation, these beetles may be an excellent indicator species for examining the effects of global climate change on native organisms in alpine environments. Ongoing research on this exciting possibility is supported by the National Science Foundation and is being conducted with undergraduates from Santa Clara University and Sonoma State University.

This research was conducted collaboratively at Sonoma State University and Santa Clara University. Sonoma State University, with 6,000 undergraduate and 1,000 graduate students, is located in Rohnert Park, CA and is a member of the California State University System. Santa Clara University is private Catholic, Jesuit university located in Santa Clara, with 4,400 undergraduate and 3,300 graduate students.

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Last Modified: 9/11/00