|Rove beetle, 12 mm Philonthus caeruleipennis - REK|
|Earwig, note pointed cerci - Wikipedia|
|Ventral view of Philonthus caeruleipennis - REK|
Typically rove beetles have short elytra covering small wings that are seldom used. Many have evolved to be flexible, able to used their narrow bodies to crawl into narrow places or to shorten their bodies to reduce their surface area to avoid dehydration. The increased exposed surfaces and junctures in their body means they lose moisture more rapidly. They overcome this by staying under humid detritus, leaves, and bark.
|Gold-and-brown Rove Beetle (Ontholestes cingulatus) - L Bower|
Specialized lifestyles means that they can lose some now redundant body parts and save the energy needed to grow and use them. Some species that live in soil and caves have lost their eyes. Others no longer need long distance transportation to maintain their species and no longer have wings.
As you might expect with such a large number of families, there is a wide variety of foods that various species specialize in. While many are saprophytic including fungi feeders, others are predatory (fly larvae and even mosquitoes) and a few eat only plants. To get even, the Laboulbeniales order of fungi are obligate ectoparasites, living on rove beetles, mites and millipedes. They get their nutrition from the animal while not usually causing significant harm to the host.
|Rove Beetle - Homaeotarsus sp.http://bugguide.net/node/view/1413817|
|Movie monster or rove beetle? - REK|
* I hope that the metric conversions don't bother you. Most scientific articles use metrics so if we are going to continue to read about nature, we need to get used to it.
The University of Florida has a good in depth discussion on rove beetles in this PDF.