Living organisms adapt to the world around them in a variety of different ways. Some may blend in to hide from predators, while others may use exotic bright colors to signal their poisonous nature to the world. Some, like the elephant, grow to large sizes. Others, like the Fairyfly (echmepterygis), prefer to shrink instead. Let's unravel how these fairies of the insect world have adapted to their microenvironment.
Physical Description and Behavior
Despite being called Fairyflies, these insects are actually wasps. The males are blind and wingless, having fairly long legs and dull grayish-brown coloration. Their antenna has no segments, which are shorter on males than females. Females of this species are black and have mandibles with teeth that overlap, which they use to chew through the eggs of their host.
Females also have a set of wings that look more like a feather than a wing. Due to their size, the air works more like a liquid, allowing them to fly around on breezes. Their eyes are so small that it is hard for them to see, causing them to rely more on smell to get around.
Fun fact: This insect is so small that it is actually smaller than certain cells, amoeba, and even a human neuron. They are actually so small that they are almost impossible to see with the human eye, yet are overall more complex than many cells. While they are small altogether, males of this species are 40% smaller than females, measuring as low as 139 μm across,
While it is possible for these insects to mate with members outside of their families, most copulation occurs via incest. Males attach themselves to females to copulate, and may still be hanging on as the female leaves to search for other places to lay eggs. Females only breed once before dying, making the lifespan of this species from only a couple of hours, to a few days.
Their eggs are so small that they need to be injected by these wasps into the eggs of host flies in order to reproduce. It is believed that the lack of resources inside of their host egg is the reason for their sexual dimorphism.
This size seems to be about the smallest that any animal can be before any of its parts stop functioning. The small number of neurons they hold are all vital, and cannot be shrunk any further. Some species even have males that have forgone their mouths, as eating and digesting doesn't matter much if you only live for a few hours.
Habitat and Location
They are mainly found in the Eastern part of North America, where their host (the bark louse, Echmepteryx hageni) lives. Since they spend a majority of time inside of the eggs of their host, they can mostly be found in the bark of trees. I cannot find any form of distribution map for this species.
These insects are parasites, killing off some insects that can harm crops. As a result, they can be used in agriculture as a form of pesticide.
You can learn some more about these creatures by checking out the video below: