Effect of magnetically simulated zero-gravity and enhanced gravity on the walk of the common fruitfly

Abstract

Understanding the effects of gravity on biological organisms is vital to the success of future space missions. Previous studies in Earth orbit have shown that the common fruitfly (Drosophila melanogaster) walks more quickly and more frequently in microgravity, compared with its motion on Earth. However, flight preparation procedures and forces endured on launch made it difficult to implement on the Earth's surface a control that exposed flies to the same sequence of major physical and environmental changes. To address the uncertainties concerning these behavioural anomalies, we have studied the walking paths of D. melanogaster in a pseudo-weightless environment (0g*) in our Earth-based laboratory. We used a strong magnetic field, produced by a superconducting solenoid, to induce a diamagnetic force on the flies that balanced the force of gravity. Simultaneously, two other groups of flies were exposed to a pseudo-hypergravity environment (2g*) and a normal gravity environment (1g*) within the spatially varying field. The flies had a larger mean speed in 0g* than in 1g*, and smaller in 2g*. The mean square distance travelled by the flies grew more rapidly with time in 0g* than in 1g*, and slower in 2g*. We observed no other clear effects of the magnetic field, up to 16.5 T, on the walks of the flies. We compare the effect of diamagnetically simulated weightlessness with that of weightlessness in an orbiting spacecraft, and identify the cause of the anomalous behaviour as the altered effective gravity.

The behavioural-driven response of the Drosophila imago transcriptome to different types of modified gravity

“…Note the differences between the two genders in over-expression (red areas) and that, for one gender, the over-expressed areas correspond to downregulated areas for the other gender. This opposite effect for males and females, which has been observed previously in our complementary experiments [18], can also be seen in lessexpressed areas of the image. This suggests a global effect in …”

“…It is established that Drosophila imagoes exhibit a marked enhancement in motility when they are exposed to altered gravity conditions, due in part to their misorientation relative to the gravity vector [18,22,23]. Recent work has shown that differences in the age and gender of the imagoes can influence the degree of responsiveness to altered gravity, and suggested that altered motility can have a consequence by reducing mating/sexual behaviour and increasing energy metabolism and aging [24].…”

“…The asterisk is used as a reminder that the labels refer to the effective gravity on water, and also to indicate that there is a strong magnetic field present (approximately 12 T at the 0g* and 2g* points, and 16 T at the 1g* point). The point at which flies levitate was determined in [18] to be close to the stable levitation point of water (i.e. close to a 0g* point).…”

“…The latter include mechanical systems such as clinostats, random positioning machines (RPM), drop towers, plus large radius centrifuges such as the Large Diameter Centrifuge (LDC) located at the ESA Research Centre in The Netherlands (ESTEC) [8][9][10][11][12][13] that allows minization of shear forces. An alternative ground-based approach is magnetic levitation, in which the diamagnetic force generated by a powerful magnet balances the force of gravity [14][15][16][17][18][19][20]. Magnetic levitation exploits the property of diamagnetism in materials such as water, starch, oils, and fats, which are normally thought to be non-magnetic.…”

To crash or not to crash: how do hoverflies cope with free-fall situations and weightlessness?

“…The effects of changes in gravity on living organisms have mainly been studied by performing complex, expensive experiments on Earth and in space (Ishay and Sadeh, 1975;Hill et al, 2012;Herranz et al, 2013). In view of the heavy investments required to perform experiments on insects on these lines, we decided to develop a lowcost platform.…”