Non-monotonic temperature dependence of nanoscopic dynamics measured in living housefly larvae

Abstract

We have studied nanoscopic dynamics on pico-to nano-second time scale in living housefly (Musca domestica) larvae using quasielastic neutron scattering. Model-independent data exhibit two distinct dynamic components measurable on the time scale probed in the experiment. The broad component is reminiscent of water dynamics, but somewhat slower, and must be associated with the scattering contribution from the hemolymph in larvae. The narrow (slow) component is similar in appearance to the dynamics measured previously in the living planarian flatworms. Unlike the monotonic temperature dependence for the hemolymph dynamics, the temperature dependence for the slow dynamic component shows an increase at 298 K, in the middle of the measured (on cooling down) range of 303.8 to 289.3 K. A similar increase at 298 K, in the middle of the measured (on warming up, and with different sample environment temperature control equipment used) range of 284.5–304.1 K, has been previously observed for the slow dynamic component in living planarian flatworms. An increase in the measurable nanoscopic dynamics at a mid-range temperature of 298 K, decoupled from the hemolymph dynamics, is an unexpected phenomenon, apparently observable among organisms from different phyla, such as flatworms and arthropods.