Mites have developed quite a niche for themselves in parasitising other arthropods, even other arachnids. Opiliones, the so-called harvestmen are often singled out by these haemolymph sucking varmints. The mites latch on to the gangly harvestman and search for chinks in its suit of chitinous armour – normally, these are to be found where the legs articulate with the body or on the legs themselves. Once the mites have found a suitable spot they plunge their mouthparts into the body of the harvestman and begin sucking its nutritious haemolymph.
The poor victim in the photo below was found in northern Spain and it was infested with no less than nine of these free-loaders. Just what harm they cause their host is unknown, but they can’t be doing it a world of good. A lot of mites are only parasitic when they’re young, forsaking this lifestyle for free, clean living as predators amongst the leaf litter when they reach adulthood. For the harvestman below this can’t come soon enough.