A little mite for a similar amount of time

A tiny, but complex mite: Nanorchestes sp.

A tiny, but complex mite: Nanorchestes sp.

I’m still swamped at work with too many mites and not enough time to appreciate them. So here’s a tiny example of what mites have to offer when one can take the time to look closely. Although scarcely more than a tenth of a millimetre in length when full grown, this mite comes complete with a highly ornamented cuticle, numerous highly branched (dendritic) setae, 2 pairs of simple eyes, 2 pairs of ciliated trichobothria (one of which forms a latch-trigger setacomplex), mysterious mouthparts, and an astounding ability to jump several times its body length.  Nanorchestes species also have an astounding ecology – a mysterious ability to thrive in cold deserts, including some of the coldest places in the World.

Most mites in this genus are poorly studied, but Nanorchestes antarcticus Strandtmann is well known.  Herds of hundreds of thousands of these mites roam parts of the Antarctic continent, presumably grazing on algae (lacking solid gut contents, the feeding behaviour of these mites is a bit murky).  As tiny as they are, Bill Block has been able to measure individual oxygen consumption rates (Oikos 27: 320-323), which at 5C in an adult female is around 368 micro-litres of O2 per gram per hour.  That may sound like a lot of CO2 entering the Antarctic atmosphere, but on a good day, a full grown mite weighs only about 3.6 micrograms, so no need to dob them in to  Al Gore.  It’s not 5C in Antarctica all that often.

D. E. Rounsevell and Penny Greenslade have a hypothesis  (Hydrobiologia 165: 209-212) that the ornate cuticle in Nanorchestes enables the mites to hold a layer of air around their bodies that increases their respiratory efficiency in seasonally waterlogged soils and perhaps keeps the ice away from their cuticle when they refreeze. Most of the two dozen or so described species in the genus are known from extremely cold areas of the World – but I think this is an artifact of funding. If you want to study animals living in Antarctica, then your are pretty much limited to mites, springtails, nematodes, and rotifers.  Well, I exaggerate, there are a couple of chironomids and I guess a few vertebrates must show up now and then, but who has the time for every little taxon. All those Nanorchestes living outside the Antarctic are pretty much ignored too. You can find Nanorchestes anywhere you can find a dry bit of soil, from the beach to a treehole in a rainforest. I can even find them in my city yard, but then this is Alberta, winter is on the way, and I know they are more cold-adapted than I am. I’d much rather be looking for Nanorchestes on a Queensland beach.

9 Responses to “A little mite for a similar amount of time”

  1. MabrotHoall Says:

    I don’t know If I said it already but …Cool site, love the info. I do a lot of research online on a daily basis and for the most part, people lack substance but, I just wanted to make a quick comment to say I’m glad I found your blog. Thanks,🙂

    A definite great read..

    -Bill-Bartmann

  2. Laurie Says:

    Love your images, I assume they are all done with a SEM?

    I wonder, could I be extremely cheeky? Could you have a quick look at the little red mites in the images on this page:-

    http://www.laurieknight.net/site.php?category=40

    and let me know, if there is enough info to go on, what you think they might be? (I think the last one of the 4 is a velvet mite, but the little tiny red ones on the moth I have no idea about!)

    Cheers!

    • macromite Says:

      Hi Laurie,

      Wow! Those are spectacular pictures. Both the small red and the larger brown mite are related to the velvet mites, but belong to the superfamily Erythraeoidea. Unfortunately, I’m not a specialist in this group, but of the two families (Erythraeidae, Smarididae), it looks the brown mite (probably an adult) probably belongs to the family Smarididae, because they characteristically have broad, flattened setae with serrate edges on their bodies.

      The small red mites attached to the moth are all larval erythraeoids, probably Erythraeidae. These mites are like chiggers, but only attack arthropods. The larva, or first active stage, has only 6 legs (adults and nymphs have 8 legs and are free-living predators). The larvae are parasites and puncture the insect’s cuticle, feed on its fluids, and become immobile. Internally, a couple of layers of new cuticle form representing the protonymph and deutonymph – the latter eventually hatches out and runs around looking for insects or insect eggs to feed on.

      My pictures are SEMs and are hand ‘stacked’ in Photoshop. Most I’ve ever put together into one image is 18 shots, so seeing an image with 93 stacked shots is very impressive. Are you using an automated camera or do you have to do your ‘bracketing’ manually?

  3. Laurie Says:

    Thanks for the kind words, ID help and further information on these!

    At the moment I have to manually adjust the focus for each slice – I use an old Oly BH base/focus block for this.

    Why do you have to stack? I thought SEMs avoided diffraction by using electrons instead of light… Or does this just move the ‘diffraction ball park’ a bit further down?

    Have you tried using auto stacking software? CZP is good and free, IMO Zerene stacker is definitely better (I think the output is marginally better but the main gain is the easy to use interface including retouching facilities) but ZS will be commercial very soon. I think the free Beta is still available for a short while..

  4. Henry Walloon Says:

    Great blog and truely amazing images.

    I’m working up to a mite posting on my own nature blog. Do you know of any reference, accessible to a mite novice (=me!), that gives an introduction to chaetotaxy. I’ve come across numerous mite papers that discuss the setae of specimens in ‘code’ (‘e2’ ‘cha’…etc etc) and I’m struggling to understand how it all works. (i..e. whether these just labels each author is making up to suit themselves, or whether there is some standard nomenclature )

    Any pointers appreciated.

    • macromite Says:

      Hi Henry:

      Chaetotaxy is both a blessing and a bane to Acarology. Many mites have highly reduced and genetically fixed chaetomes and knowing the correct setal designations can be a map to their identity. Unfortunately, every other acarologist who has come along has invented their own names for the setae. The literature is a Tower of Babel! Partly this is because there are at least two major lineages of mites, the Acariformes and the Parasitiformes, and it isn’t at all clear if they form a monophyletic group or if they represent two different evolutions of a mite grade, and it has been impossible so far to homologize their setae. Most of the problem, however, can be laid down to eccentric acarologists each going their own way.

      Over the last couple of decades, there has been a trend towards standardization of setal nomenclature, at least within large groups. The recently published “Manual of Acarology” 3rd Edition (Texas Tech University Press 2009) goes a long way towards standardization. I would recommend the Manual (but since I am one of the authors, of course I would!).

  5. Henry Walloon Says:

    Macromite,

    Thanks for the pointers. I’ll seek out the Manual of Acarology.

    I’ve been writing up a posting about a macrochelidaew mite and have given your splendid site a link.

    regards

    Henry

  6. Of Knots & Worms Not: Gordialycus « Macromite's Blog Says:

    […] dry habitats or dry microhabitats within more mesic ones. Both hot and cold deserts (e.g. see the Nanorchestes I’ve posted on before) have more than their share of endeostigmatans. Members of the Nematalycidae […]

  7. “You’re Getting Colder” – How Terrestrial Animals Survive in Very Cold Climates | Corner of the Cabinet Says:

     The only true terrestrial species I was able to find that persist in the Antarctic proper were a few invertebrates; with the hardy little phytophagous mite Nanorchestes antarcticus claiming the title of “most southernly invertebrate”.  Apparently hundreds of thousands of these mites persist in roving bands grazing on algae.  If you’re curious about them, you can learn a bit more here on Macromite’s blog. […]

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