MITES AND TICKS (ACARI)
Tilling (1987) cites 1500 species “and many more still to be found”; this is the same number that is listed by Turk, F.A. (1953) (including subspecies and excluding gall mites of uncertain status). Acari present a large array of forms and lifestyles. The common names of some of the groups indicate something of the diversity: soil mites, freshwater mites, marine mites (the Halacaridae, discussed under the marine section), spider mites, gall mites, house-dust mites, mange mites, lung mites, flour mites, sugar mites, harvest mites and so on. Some of those that live in leaf-litter play an important part in its reduction, whilst others feed on stored dry products causing much damage. Ticks are implicated in Lyme disease as well as some ailments of livestock, whilst other much smaller mites cause scabies and demodetic mange. Pugh (1988) records a number from the Cornish shores and Hyatt (1993) records 169 species from the Isles of Scilly but has no further to add (2008 pers. comm.). Other Cornish records are included in various papers by F.A.Turk. Their minuteness (most are under 2mm long) and their various means of effective dispersal result in an evenness of distribution.