The Bigger They Are, The Harder Gravity Is On Them: An Examination of G-Force and Insect Survival

Among other differences between vertebrates and invertebrates, the extent to which the two tolerate extreme gravitational forces differs greatly.  The large forces generated by some insects, simply by jumping from leaf to leaf, would be lethal to any vertebrate.  This experiment tested the range of survivable forces for insects, as well as how the size of an individual contributed to its survival.  To test g-force tolerance, insects were spun in a centrifuge at intervals of increasing acceleration, until the organism was no longer living or was mortally injured.  Tests were performed on fruit flies, Drosophila melanogaster, various sizes of house crickets, Acheta domesticus, mealworms, Tenebrio molito and Zophobas morio, and Madagascar hissing cockroaches, Gromphadorhina portentosa.  The tolerance of g-force ranged from more than 9,000 in fruit flies to about 1,400 in the largest hissing cockroaches.  All insects that weighed more than 0.1 grams had similar tolerance of between 1,600 and 1,400 g-forces suggesting structural failure of intersegmental membranes resulted in mortality.  These results show a constraint of insect size based on exoskeleton properties and are being developed as a laboratory exercise for biology and entomology classes.