Meeting Abstract
When studying insect biomechanics, it is crucial to understand the materials properties of blood at different time and length scales. Insect blood is a suspension of adherent and non-adherent micron-sized cells suspended in plasma. Even though at the macro-scale the suspension may behave as a single-phase liquid, it has been a long-standing challenge to measure its materials properties at the micro- and nano-scales, where the effects of cells can be significant. Magnetic Rotational Spectroscopy allows one to probe these multi-scale rheological properties in real time. We quantitatively study nucleation of cell aggregates that occurs within fractions of a second. Using larvae of Manduca sexta, we discovered that clot nucleation is a two-step process whereby cell aggregation is the time-limiting step followed by rigidification of the aggregate. Clot nucleation and transformation of viscous blood into a visco-elastic aggregate happens in a few minutes, which is hundreds of times faster than wound plugging and scab formation. In contrast, hemolymph of adult lepidopterans is a Newtonian viscous fluid. Hemolymph of Monarch and Painted lady butterflies and Manduca sexta moth still shows surprises: a threefold difference in viscosity between these species suggests an important physiological implication of hemolymph constituents most likely related to the flight fuel. 1. Aprelev, P., Bruce, T.F., Beard, C.E., Adler, P.H., Kornev, K.G. Nucleation and formation of a primary clot in insect blood, Scientific Reports, 9, 3451(2019)
