image: This is a Melanoplus sanguinipes (migratory grasshopper). view more
Credit: John J. Socha
The body position of the American grasshopper strongly affects its physiological responses, according to a study. In vertebrates, the circulatory system rapidly responds to changes in body position to compensate for gravity and continue to deliver sufficient blood. Jon F. Harrison, Jake Socha, and colleagues examined the effects of gravity on the invertebrate circulatory system, which has few mechanisms to restrict the flow of the hemolymph. To address the technical limitations of measuring such small systems, the authors used synchrotron video X-ray imaging, radiotracing of hemolymph, and micropressure measurements to determine physiological responses to body orientation. Body position not only caused significant changes in blood and air distribution, but also in ventilation rates. Changes in heart rates relative to body position were similar to vertebrates, suggesting physiological compensation. In addition, the measured pressure differences between the thorax and abdomen suggest a flexible valve system for maintaining different compartment pressures and reducing effects of gravity on blood flow. According to the authors, the detection of such dramatic responses suggests that gravity-driven cardiovascular responses may be ancient and widespread.
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Article # 19-15424: "Physiological responses to gravity in an insect," by Jon F. Harrison et al.
MEDIA CONTACT: Jon F. Harrison, Arizona State University, Tempe, AZ; tel: 480-965-9459; e-mail: <j.harrison@asu.edu>; Jake Socha, Virginia Tech, Blacksburg, VA; tel: 540-231-6188; e-mail: <jjsocha@vt.edu>
Journal
Proceedings of the National Academy of Sciences