How are ants able to move/pull objects that are heavier than the insect?
Sehore, Madhya Pradesh
Can we imagine carrying ten-time heavier objects than our body weight? It may be possible for the ‘ super-man', but not for an ordinary man. However, ants could carry or pull objects weighing several folds heavier than their own body weights.
Do ants possess stronger muscles that enable them to produce more strength than humans? The answer is ‘NO', according to Sir Vincent Brian Wigglesworth, the ‘Father of Insect Physiology' who compared and found no differences between the muscle force (per unit area) of insects and vertebrates. Then what enables the ants to carry heavier objects is their relatively smaller body size.
According to the square – cube law, when an object undergoes a proportional increase in size, its new volume is proportional to the cube of the multiplier and its new surface area is proportional to the square of the multiplier. When an animal grows in length (or height), the volume increases in cube but the cross sectional area of its muscles increases only in square.
Mass is the amount of matter in an object, and hence the (cubic) increase in volume tends to increase the body mass significantly, whereas the cross-sectional area of the muscles increases in a much slower rate (only in square). Hence, these cross sectional areas of muscles have to support relatively more mass and thus larger animals like humans need to put most of the muscles in use to carry their own mass.
In other words, larger animals have to carry their own weight, besides the heavier objects; so they are able to carry only slightly heavier objects. However, because of the smaller body size, the body mass of ants is much lower and hence they put fewer muscles into use to carry this body mass. Thus, ants could use more muscles to carry bigger loads than their own mass, which not only applies to ants, but also holds good for most of the insects. However, since ants are quite abundant in human habitats, we frequently seeing them carrying bigger cuisines or pulling heavier objects.
Entomologist and Head of Entomology Group
AVRDC-The World Vegetable Center
Keywords: Insect Physiology