Of all the creatures in the animal kingdom, few have adaptations as remarkable as insects. Living in virtually every corner of the world, insects have evolved in ways that enable them to thrive within their respective ecosystems.
Exoskeletons and Molting
The big thing that separates us from insects is where we keep our skeletons. While we keep our bones inside our bodies, insects have exoskeletons: hard, shell-like structures made of a tough substance called chitin. Exoskeletons provide insects with solid protection against the dangers of the outside world.
Exoskeletons do not grow along with the insect, as our bones do. To solve this problem, insects periodically go through a process called molting, in which they crawl out of their old exoskeleton and develop a new one. Insects are very soft and vulnerable in their newly molted state, but the protection that an exoskeleton provides is well worth the risk.
Stingers, Pincers and Poison
While we may not like bugs that bite or sting, these adaptations give certain insects a remarkable advantage. By being able to cause pain to animals exponentially larger than themselves, insects have a solid means of defense in a world where they would otherwise be extremely vulnerable.
The use of venom does not come without a price. It takes a lot of energy for insects to bite or sting, and so they will not do so without provocation. In the case of the honeybee, leaving a stinger behind typically rips them in half, resulting in death.
Insects are not generally poisonous to humans, though their bites and stings can be very painful. Some people may suffer allergic reactions to their venom. More commonly, the danger with biting insects comes from the diseases that they can spread.
Insects can live in just about any climate. There are few places on land where we haven't found insects. In hot climates, insects may burrow in the sand to keep cool, or adopt nocturnal behavior to avoid the heat of the day.
Insects have been found in cold climates as well. For example, the Nebria beetle, also known as the ice beetle, makes its home on icy tundras and glaciers. Its body contains a fluid that acts much like antifreeze, keeping the beetles alive and healthy in temperatures that most animals would find very inhospitable.
Insects have compound eyes, which are made of multiple lenses known as facets. The number of facets in a compound eye can range from the tens to the tens of thousands, depending on species. This strange adaptation means that insects have very poor long-distance eyesight, but when dealing with objects up close, they can see in nearly every direction.
If you've ever seen a housefly up close, then you've probably noticed the hairs on its feet. Believe it or not, they can taste through these, as can many other species of insects. Other insects may have similar hairs on their abdomens or their antennae.
Taste is not the only sensation that insects have evolved to process uniquely. Some insects have receptors on their abdomens or wings that make them highly sensitive to surface vibrations or changes in air currents.