Feather mites
As feather mites are called on or in the feathers of birds parasitic mites . They occur worldwide before and according to recent epizootiological studies all recent birds with the exception of penguins are affected. These mites can be detected in about every second animal, but often without symptoms of the disease .
Classification
The various groups of feather mites are in part not closely related and are in different orders of the mites. According to the location of the mites, one differentiates
- Feather mites that grow on the feathers (usually on their underside),
- Quill mites (family Syringophilidae) that live in the quill as well
- Bellows mites (family Harpyrhynchidae) that parasitize in the bellows .
About 2000 species of feather mite are currently known. Most of them can be divided into the superfamilies Analgoidea and Pterolichoidea with 33 families and 444 genera in the suborder Oribatida of the mite order Sarcoptiformes . Quill mites and bellows mites come for the most part from the superfamily Cheyletoidea of the suborder Prostigmata in the order Trombidiformes . A feather mite species was first described in 1775 by Johann Christian Fabricius , the mite Analges phaetontis . Acarus chelopus Herrmann followed in 1804.
Feather mites not only have a strict host specificity, but are for the most part even adapted to certain types of feather (e.g. swinging hands). The great host specificity has recently also been used for systematic studies on the phylogeny of birds.
Morphology and way of life
Feather mites are between 300 and 1500 micrometers in size and very variable in their external shape. Even within a species there are great external differences between males and females ( sexual dimorphism ) and adults and the larval and nymph stages .
The diet has not yet been finally clarified. It is presumed that the diet comes from skin flakes, feathers, bacteria and fungi and, above all, from the secretion of the rump gland , although feather mites also occur in bird species that do not have a rump gland (e.g. woodpeckers ). So far nothing is known about the diet of the quill mites.
The entire development takes place in the plumage. Reproduction is sexual and begins after the moulting of the host. The females mostly lay eggs, and viviparous reproduction is also known in very few species . Eggs are usually laid between the feather branches. The eggs are visible to the naked eye as whitish coatings. The adult mite develops through a larval stage and two nymph stages. The development cycle of the quill mites takes place entirely within the quill.
The infection usually occurs during the first days of life from the parent to the chick when huddling through contact. Indirect transmission to sand bathing areas is also possible. In the case of the cuckoo , which is not raised by its own parents and is not susceptible to the mites of the surrogate parents, the transmission takes place during mating.
proof
If the infestation is severe, both the eggs and the mite colonies can be detected as light or dark spots with the naked eye or a magnifying glass. The examination under a stereo microscope has more precise informative value .
Quill mites can only be detected after opening the quill under the microscope, in some species also by means of characteristic boreholes. Bellows mites can be identified by opening the bellows and then microscopic detection.
After the death of the host, feather mites leave the host very quickly, so that evidence of infestation is only possible on living animals or on animals that were placed in a plastic bag immediately after death.
Harmful effect
The harmful effect caused by feather mites is a controversial issue. The main causes of damage are an increased urge to clean (scientifically controversial) and the withdrawal of the rump gland secretion. Other authors consider the feather mites to be harmless commensals . More recently, its importance as a vector for pathogens and as a trigger of allergies ( proven in pigeons and budgies ) has been discussed.
So far, nothing precise is known about the harmful effects of feather-reel mites.
Bellows mites can lead to nodular inflammation of the bellows and the failure of individual feathers, emaciation or even death if they are heavily infested.
Combat
Feather mites are sensitive to most ectoparasitics and are therefore easy to control. In addition to pyrethroids and carbamates , ivermectin or selamectin can also be used.
swell
- ↑ Schöne, R .; Sachse, M .; Schmidt, V .; Schmäschke, R .: Feather mites - widespread, but little known. Small animal specifically 8 (4) / 2005, pp. 26–32.
- ↑ Gaud, J. and Atyeo, WT: Feather mites of the World. Part 1, Part 2, Annales Sciences Zoologiques 277/1996 .
