The "Mitey" Beetle

Explanation: Look closely at this unidentified species of carrion beetle I found one night outside my hut in the heart of the Congo River Basin. It is carrying a number of hitchhikers.

These tiny passengers are mites, which are arthopods like the beetle but belong to the class Arachnida like spiders and scorpions. Worldwide, there are nearly fifty thousand species of mites described thus far. Mites cover an amazing spectrum of life histories including free-living in soil and water, parasites on animals, living on plants, and associated with dust in your home and causing allergies.

But some are symbionts that live on insects, such as bees and, in this week's featured photos, beetles. Although some refer to this association as parasitism -- which in some cases may be true if the host insect is harmed -- there are known cases of beetle-mite mutualism whereby both species benefit. How can that be?

In some cases, such as with carrion beetles, the mites benefit by having free transportation and access to food sources otherwise inaccessible. The carrion beetle benefits by having the mites consume eggs and larvae of other insect such as flies that would otherwise take the beetle's food. So both beetle and mite come out ahead.

In other cases, such as with mites adhering to the bodies of dragonflies, the relationship might be more one way, with the mites getting free rides and possibly access to left-over food, but with the dragonfly being neither harmed nor helped. In this case, the relationship is called commensalism.

Some beetle mites hitch a ride by hiding underneath the beetle's elytra, which is the hardened cover that folds over the wings. The tiny space beneath is a perfect hiding spot for a tiny mite.

The closer I look at the little things that run the world, the more amazed I am, and the more worried I become about their -- and our -- future.

Special notice:
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Stick around!
Next week is EPOW's
tenth anniversary!

EPOW - Ecology Picture of the Week