Monday 13 March 2023

Velvet Mites

This animal is: real


Note: There are several families of velvet mites, here I talk about the True Velvet Mites belonging to the family Trombidiidae. The above picture depicts a generic true velvet mite rather than any particular species. This is because information on specific species is hard to come by. So, here I talk about true velvet mites in general. There will be both vague remarks and sweeping generalisations! 

These mites can be found walking about in plant litter (and on walls) pretty much the world over. Typically bright red (although some are orange or come with pretty white splotches) they are some of the most conspicuous mites around. They are also HUGE (by mite standards), most are around 4 mm in length, but the mighty Giant Velvet Mites of the genus Dinothrombium reach up to 12 mm long. 12mm!! That’s like the size of a fingernail! 

When I think of velvet mites, I think of the adults. The eight-legged fluff nuggets wandering around looking for little bugs to eat or sometimes stuff to scavenge. 

But they don’t look like this all their life – they actually have quite a complex life cycle involving lots of stages: egg, pre-larva, larva, protonymph, deutonymph, tritonymph and adult. Basically, as babies they only have six legs. These youngsters are parasitic and feed on the haemolymph (bug blood) of insects and arachnids. They are the shiny red dots you may have seen clustered on the legs of harvestmen or the bodies of butterflies. Most do not harm their host (although I can’t imagine the host enjoys carrying the little vampires around). Once they’re done sucking, they detach and moult, becoming eight-legged adults. The adults of most species are covered in lovely velvety fuzziness and have small eyes on little stalks. 

Royal Natural History volume 6 (1896) edited by Richard Lydekker has a section on the species Trombidium holosericeum which includes a little picture, and has some delightful description of the animals, which are referred to as “Velvety Mites”: “They are beautiful and striking objects, resembling tufts of bright blood-red plush.” 

Its bright colour results from carotenoids and warns predators that the mite is toxic if eaten. 

I’m usually not keen on parasites, but I will make an exception for these fluffy fellas. 

External links:

The bit of Royal Natural History volume 6 (1896) I quoted from on Wikimedia Commons

Some photos of a giant velvet mite from Malawi on iNaturalist. You can see how huge it is! 

A photo of a baby velvet mite on Wikimedia commons. It actually looks kinda cute as it drinks the innards of a harvestman. 

Information on velvet mites from the genus Allothrombium on Les carnets nature de Jessica (Jessica's nature notebooks)

Information on mites, including velvet mites, on A Chaos of Delight