UF/IFAS: UF/IFAS researcher: Insects increase metabolism to adapt to dramatic weather change

Daniel Hahn

A recent study led by a University of Florida Institute of Food and Agricultural Sciences researcher found that an insect has evolved metabolically in response to an increase in weather cold snaps.

Daniel Hahn, an associate professor in the entomology and nematology department at UF/IFAS, led a team of researchers from UF, the University of California Berkeley, the University of Alabama-Birmingham and Kansas State University in the study of the fly, Drosophila melanogaster. Researchers found that selection to recover more quickly from cold snaps also drove the evolution of higher metabolic rates.

“While we hear a lot about warmer weather in spring and fall, weather fronts will continue to bring bouts of cold,” said Hahn, whose research focuses on ecological and evolutionary physiology. “This makes the transitions from warm to cold temperatures more extreme, and increases the vulnerability of animals and plants to damage from snap freezes.

“Small animals that rely on the environment to regulate their body temperature—like insects, frogs, and even sea turtles—are also susceptible to stress and even death from extreme cold fronts. We found clear changes in metabolism of the fly as it evolves and adapts to the cold snaps.”

Many studies of the Drosophila melanogaster over the past three decades have shown that populations from cold places had different forms of key metabolic enzymes, Hahn said. Though researchers believed that this relationship between metabolic enzyme forms and climate caused differences in metabolism, they had not previously been able to show differences in the flow of materials through metabolism.

Hahn and the research team applied metabolic tracer techniques commonly used in humans to study metabolism, and adapted them for use in tiny flies to test this long-standing hypothesis.

In addition to increased respiratory metabolism, the researchers showed that cold-adapted flies have greater flow of both glucose and amino acids through central metabolism, allowing them to rapidly transfer nutrients throughout their body in order to resist cold stress, Hahn said.

An important implication of the study, said co-author Caroline Williams, previously a postdoc at UF and now an assistant professor at University of California, Berkeley, is that sustaining higher metabolic rates at rest may require animals to eat more. “In environments with limited resources this kind of metabolic adaptation to recover quickly from cold may simply be too costly,” she said. “Thus, this work may have implications for understanding whether harmful insects like mosquitoes and beneficial insects like pollinators, or natural enemies of crop pests are likely to adapt or die out in the future.”

The study is published in the journal Proceedings B.

This article was originally published by UF/IFAS
Beverly James, UF/IFAS