Let’s dive into the science of insect acceleration toward the ground. Insects are small and lightweight and appear to get away from injuries when they fall from great heights and even when we step on one. Thus, it’s natural to wonder if they are actually invincible.
So the question is, do insects take fall damage? Let’s find out.
- Many insects fly. Let’s just get the obvious one out of the way. If an insect can fly, it is unlikely to reach the ground. And even if they do, they would have already decreased their falling speed by a rapid flapping of wings.
- Sturdy exoskeleton. Insects don’t have inner bones as we do. Their skeletons are on the outside, and their muscles reside inside them, protected from shocks. Of course, true, you can squish an insect, at least a small one, between your fingers easily, but you are quite strong comparatively. For their size, the insect exoskeleton is noticeably stronger than our bones. It is actually very similar to a crab’s shell and we actually use tools to get inside one, even after hours of cooking. And besides being strong, the exoskeleton is made from a protein called chitin. It is very flexible, thus less likely to fracture, and provides shock absorption for what’s inside.
- The terminal velocity of insects is small. Now, what is that? Terminal velocity is the maximum velocity that a falling object can achieve. Physics assignments usually ask to ignore the air resistance as negligible. But it isn’t, especially for smaller critters, such as insects. Air resistance increases as the object falls and gains speed. At a certain speed, the force of air resistance will be equal to the force of gravity, and they will cancel each other out. And no, the bug will not levitate; it will continue to fall with a constant speed but won’t accelerate any further. This speed is the terminal velocity, which in general, is lower for small and flat objects. Definitely smaller for insects compared to elephants or cats. Speaking of cats.
- Insects have the righting reflex. Cats always land on their feet but are certainly not the only animal to manage this skill. Many animals can do it, with varying success, and insects are among the ones that are good at it. For example, flies and bees can right themselves mid-flight if they collide with something and lose balance. Flightless insects, such as ants and stick bugs, on the other hand, can right themselves when falling. Even more so, certain ants have even learned to glide. One tree-climbing ant species even dive from a tree branch if an ant-eating bird arrives. They will right themselves mid-air, glide toward the tree trunk, attach to it and climb back up when the danger is gone.
- But sometimes insects do take fall damage. Especially larger ones that may have terminal velocities of up to 20 m/s. The authors who observed gliding ants also mention that some of them will fall to the ground anyway, and some will get injured. Then there’s also a weird part of science where insects (fruit flies, for that matter) are model organisms for head injury research. There are many ways how a scientist can induce a head injury in a fly, but all of them involve rapid acceleration and rapid stopping. However, for a head-on collision with a glass surface, it is known that an impact speed of as little as four meters per second is enough to induce a head injury, which results in behavior changes and a reduced lifespan.
There is one conclusion that we can make of the latter, and it’s that fly scientists are not normal. And that is coming from me, who also studies these little critters in the lab. However, it lets us know that, though insects usually don’t take fall damage due to low terminal velocity and sturdy exoskeleton, sometimes they do.