Insects are about to be analyzed in a new way by a host of Virginia Tech engineering faculty. They will be using some fancy state-of-the-art equipment, such as a kilometer-long synchrotron x-ray light source, which might be enough to scare any bug. And first up will be beetles, grasshoppers and silk moths because they have some endearing characteristics.
The results could be a deeper understanding of how to manage insects, with the potential to lead to advances in agricultural, commercial and residential pest control. In addition, this first engineering study of the internal fluid flows of insects, creatures that have evolved efficiently over millions of years, may provide engineers and scientists with new ideas for how to build better artificial tissues and organs, and for the design of new medically implantable microdevices.
The National Science Foundation (NSF) calls this work part of the Emerging Frontiers in Research and Innovation. NSF has agreed to support this effort, spearheaded by Jake Socha, assistant professor of engineering science and mechanics (ESM) at Virginia Tech, for the next four years with a $2 million award. http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=0938047
Virginia Tech's Institute for Critical Technology and Applied Science (ICTAS) has also agreed to support this research as a "Grand Challenge" project for the next three years with an award of $298,466.
Working with Socha is Jon Harrison, a professor at Arizona State University's School of Life Sciences, and three additional investigators from Virginia Tech: Raffaella DeVita and Anne Staples, assistant professors of ESM, and Rafael Davalos, assistant professor of biomedical engineering. ESM's Ishwar Puri, Shane Ross, and Mark Stremler, as well as electrical engineer Masoud Agah and mechanical engineer Pavlos Vlachlos, all of Virginia Tech, round out the team of investigators.
Engineers like to talk about the mechanics and dynamics of flow, and they have studied this field for decades. But Socha and his team want to apply their knowledge of how insects manage fluid flows at the microscopic level for bioengineering purposes. And to do so, they envision harnessing "the agility, dynamic range, low power requirements, self-contained nature, and efficiency of the flows on specific insects' respiratory and circulatory systems to revolutionize the design of microfluidic systems," the team explained.
Insects are often considered to be the most successful group of living species in Earth's history. Unlike mammals, insects breathe by transporting oxygen directly to tissues without the help of a circulatory system. "Their complex air-filled tracheal network delivers oxygen from the environment directly to the tissues, and conversely transports carbon dioxide from the tissues directly to the environment," Socha said.
In previous research, Socha and colleagues opened a new window into the inner workings of insects by using synchrotron x-ray imaging to enable the direct visualization of internal microstructures in living animals. According to Socha, "a key finding was a new form of convective respiration termed 'rhythmic tracheal compression' in which parts of the animal's tracheal system collapse and reinflate on the order of 10 to 20 times per minute."
Although scientists do not yet know exactly why some insects use this respiration process, it could be that "compressions function to target airflow to specific internal tissues, such as the heads of legs, and to keep oxygen partial pressures high for sudden fast movements like escape or for the regulation of acids and bases within their bodies," Socha said.