Black-and-White Soil Mite from Terrarium

2022 January 30

I decided that now would be a good time to get more practice using my extreme macro lens to look for extremely tiny arthropods in the soil. Everything outside is buried under several feet of snow as of now (January 30, 2022), and so our best option is to look for things in the soil for our houseplants. This one is an extremely tiny mite that we found in soil from a terrarium that we have had in a 2-gallon glass jar for, oh, probably three years now.

When I say “extremely tiny”, I mean “almost invisible to the naked eye”. In this next picture you can see the mite down in the lower left corner. And in the upper right corner, you can see the very tip of a standard ball-point pen. The ball on the tip of the pen is around 0.8 millimeters, which makes the mite itself maybe half that, or about 0.4 mm.

It was also pretty well camouflaged, allowing it to blend in with the general debris in the soil. Honestly, the only reason we spotted it at all was because it crawled over a larger crumb of dirt, and made it wiggle visibly.

So anyway, this is definitely a mite, which is a large group of arachnids that have eight legs and only one body segment. I expect it is one of the Acariformes. According to BugGuide, this is a superorder with at least 30,000 known and described species, and probably hundreds of thousands of species that have not yet been characterized. It also says that “they inhabit every biotic or abiotic habitat in the world”. But many of them (like this one) are so very, very tiny that they never get noticed unless somebody looks really closely.

Anyway, this is obviously one of the “soil mites”, which just means it is one of the mites that eat decomposing matter in the soil. It isn’t like they are an actual group of closely related mites, they just happen to have all moved into the soil habitat. Almost all of these are beneficial organisms, breaking down the soil in a way that allows plants to extract nutrients from it. So if you find little mites crawling around in the soil of your houseplants, this is not only not something to get concerned about, it is probably inevitable.

I don’t think that this particular species has been photographed and put up on the internet before, at least I’m not finding anything like it. Which, given how many undescribed soil mite species there are, is completely unsurprising.

One Response
  1. February 4, 2022

    Here’s your chance to classify a new mite! I can see it now: Acari Oribatida Caticus! The name just rolls off the tongue, don’t you think?

    A bug that tiny must be dining on liquids, no? Does it have any way to chew things?

    Also – Fabulous photography, as always. What a lens! It deserves a skilled hand, which you have.

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