Gunnar wanted to see some different kinds of microarthropods, so here is one that is too little seen – the front end of an acerentomid proturan. Proturans seem to be fairly common in forest soils in many parts of the world (this one is from Queensland), but I have yet to see one in Alberta. Of course, 10,000 years ago Alberta was buried under a kilometer of ice, so they may be on their way, but yet to arrive.
According to The Insects of Australia, proturans “are said to feed on mycorrhizal fungi”, but if I remember the paper this is probably based on, it was more correlation than actual observation. It seems strange that the feeding behaviour of an entire Class of Arthropoda remains unclear, but last I heard what the Pauropoda eat was unknown too. I should add that I tried several times to obtain feeding observations on both groups and all I got was deceased animals (and probably bad karma).
Proturans are blind: the eye-like structure on the head is a pseudoculus and is thought to have ‘olfactory or chemosensory’ (Insects of Australia) functions, but a similar appearing organ in pauropods is thought to sense vibrations. There are a number of published studies of the ultrastructure of the organ in both groups, but alas, the journals are not available at my library. Unfortunately, this is often true for publications on the biology and morphology of soil microarthropods.