Asked by: Remmy Osman, Marlow Bottom
G ‘force’ is actually an acceleration. 1G is equal to the acceleration due to Earth’s gravity at sea-level, or 9.8m/s2. Newton’s second law states that force equals mass multiplied by acceleration, so for a given acceleration, heavier objects experience a greater force. This gives insects a big advantage over us because they weigh tens of millions of times less than we do.
The froghopper bugs of the Cercopoidea superfamily accelerate at 400G when they jump, but because they weigh so little, this requires less than 0.04N of force. That same force would generate an acceleration of 0.00005G for an adult human.
In humans, high acceleration causes the blood to slosh to one end of the body. This causes burst blood vessels and starves the tissues of oxygen at the other end. Insects don’t have a circulatory system so the limit of their endurance is just the mechanical stress their body can absorb. Basic calculations suggest that you accelerate a fly by 200-400G when you swat it in mid air with a rolled up newspaper, so lethal G-forces are probably of this order for most insects.