The data about the biology of bird-associated prostigmatans are very fragmental and far from complete; nothing is known about the biology of Pneumophaginae and Speleognathinae.
All prostigmatans permanently associated with birds possess piercing chelicerae and feed on live host (or prey) tissues. The exception are males of Pneumophagus bubonis, their chelicerae are lost but oral opening is still present. There are two types of food specialization in skin-inhabiting prostigmatans: lymphophagy (most prostigmatans) and haematophagy (Bakericheyla). Females of these mites lay eggs on the host body. Normally their life-cycle includes active larva, two nymphal stages and adults, females and males; no cases of parthenogenesis were recorded. The immatures of Pneumophagines, however, are still unknown and all nymphal stages of Speleognathinae are calyptostatic. The life-cycle of prostigmatans studied in this relationship is short. In free-living cheyletids (Cheyletus) the time of life-cycle critically depends from temperature and takes from 10 to 80 days. In syringophilids, it takes about 40 days. In symbiotic cheyletids and harpirhynchids these characteristics should probably be similar.
Prostigmatans, being permanent symbionts, colonize new hosts by two main ways – from parents to nestlings and in the time of contacts between adults (particularly during molt of gregarious birds or at breeding time). The first way is especially characteristic for syringophilids. Is worth to note that in syringophilid mites only fertilized females disperse from one host to another, whereas the males never leave the feather quills.
The population ecology of bird-associated prostigmatans is weakly studied. They are characterized by relatively low prevalence index (IP). For parasitic cheyletids (Bakericheyla chanayi and Ornithocheyletia sp.) it was estimated for different seasons and hosts as 0.4-8%. According to Kethley (1971) and Skoracki (2011) , IP in syringophilids is very low for the wild, non-social, and separately nesting hosts, for example, IP for Lanius excubitor parasitized by Syringophiloidus weiszi is 3.5% (N=508). In the same time IP for Hirundo rustica infected with Syringophiloidus hirundus is 17% (N=208). The data about syringophilid IP on wild birds has been recently summarized and discussed by Skoracki et al. (2010). The highest IP was shown for social and domestic birds, e.g. IPfor Passer domesticus infested by Syringophiloidus minor is 82% (N=492), or IPfor Gallus gallus domesticus is 75% (N=1.500). In Harpirhynchidae, various species of the genus Neharpyrhynchus demonstrated on the European birds 2-14% IPs and 15-21% on birds in Peru; mites of the genus Harpirhynchus dusbabeki from Panurus biarmicus in Europe showed IP 7.4% (N=378).
The damage caused by prostigmatans to their avian hosts is markedly varied. Most of these mites (probably) do not cause a huge loss of bird condition. Some cyst-forming harpirhynchids are considered as harmful parasites. At the same time Henry et al. (2004) did not find a markedly negative impact of the lesions by harpirhynchids on the health status of birds infected. According to Literak et al. (2005), the traumatic effect from harpirhynchid cysts was also not too serious and it seems that birds with cysts survived for a long period.
In contrast to some reports about the clinical signs of feather’s picking caused by syringophilid mites (mostly Syringophilus bipectinatus) in domesticated birds Skoracki (2011) found no evidences that quill mites induce the pathological changes in the structure of skin in wild birds, even during heavy infestations. Casto’s (1974) observations also indicate that the exit channels and many small holes produced during feeding activity of syringophilids, do not seem to weaken the structure of the feather.
The role of prostigmatan mites as vectors of bird diseases is almost unstudied. It is only known, that syringophilids could be potential vectors of bacterium Anaplasma phagocytophilum - an obligate intracellular pathogen.
References: Bochkov and OConnor 2008; Akimov and Gorgol 1990; Kethley 1971; Andre and Fain 2000; Skoracki 2011; Literak et al. 2005, 2012; Martinu et al. 2008; Moss 1979; Rebrassier and Martin 1932; Schwabe 1956; Hwang 1959; Gritschenko 1973; Schmaschke et al.2003; Principato et al. 2005; Skoracki et al. 2006.
