Miniaturized Insects

There are insects that are smaller than single cells. These are the fairy flies or fairy wasps, and they are thought to be the smallest size insects can physically get to.

Their bodies are extremely simple. They have structures analogous to the antennae and legs of larger insects, but with fewer segments. They can also afford an extremely miniaturized circulatory and respiratory system because they obtain oxygen directly by diffusion, so much so that the smaller species have no blood vessels and hearts.

Some tradeoffs due to the small size cannot be avoided, however. The tiny space in their heads is at the limit of what is needed to bend and absorb light, thus they have lower visual acuity than most insects. The males of some species lack eyes altogether, since they rely mainly on their sense of smell. Some also lack wings, and even their mouth. Because if you only live a few days, you don’t need to eat.

In the few species that have them, the wings are oar-shaped, with a frill around the edge that looks like a feather. They act more like a paddle, since at that size the air feels much thicker.

Even their cells, in addition to being fewer, are smaller. Some of them super-condense their DNA to shrink down their nuclei and overall size.