Chaetodactylus

''Chaetodactylus'' is a genus of parasitic mite primarily associated with solitary bees with over 20 species.

These mites usually kill young bee larvae and feed on provisioned pollen and nectar. In nests with partitions (''Osmia''), bees that develop in the innermost cells chew their way out of the nest, and phoretic deutonymphs from the opened cells may attach to them. The mites in the innermost cell may die because of their inability to break through the partition. In nests without partitions (''Lithurgus''), some young bees may complete development and transform to adults that disperse the mites.

In colonies of ''Osmia cornifrons'' managed for pollination of blueberries in the US, '' Ch. krombeini'' phoretic deutonymphs could disperse from a nest to nearby nests by walking through nest entrances and holes made by parasitic wasps. Cross-nest dispersal via blueberry flowers visited by multiple individuals of '' O. cornifrons'' was proven to be negligible.

Life cycle

Feeding stages live in bee nests. They are mostly kleptoparasitic, but they may kill developing bee larvae via direct attack.

Phoretic deutonymphs (non-feeding stage) disperse from one nest to another on adult bees. They cause no direct harm, but large mite loads may affect the bee's flying abilities and survival. In managed and aggregated bee colonies, they may infect new nests by active dispersal (walking).

Non-phoretic deutonymphs (non-feeding stage) can survive in the nest cavity to infest new bee generations, if the same nest is reused.

File:Chaetodactylus micheneri immob.jpg, ''Chaetodactylus micheneri'' non-phoretic (immobile) deutonymph.
File:Ontogeny Chaetodactylus krombeini.jpg, Life stages of Chaetodactylus krombeini (Astigmata); non-phoretic deutonymph and male not shown.

The presence of the inert non-phoretic deutonymph along with the phoretic deutonymph is the most conspicuous feature in the life-cycle of this genus. The inert deutonymph is a highly regressive, cyst-like morph with legs and most setae greatly reduced. It is capable of surviving in old bee nests and infesting new hosts that reuse these nests or the nest material. When mites are trapped in the innermost cells of an infested nest or all bee larvae are killed and therefore cannot transfer mites to a new nest as adults, inert deutonymphs can be very important for mite survival.

Systematics

* Subgenus Chaetodactylus Rondani, 1866 (Also called ''Trichotarsus'' Canestrini, 1888)
** ''Chaetodactylus chrysidis'' Fain & Baugnee, 1996 — host: Chrysura trimaculata;
** ''Chaetodactylus dalyi'' Fain, 1974
** ''Chaetodactylus hirashimai'' Kurosa, 1987 — host: Osmia excavata;
** ''Chaetodactylus ludwigi'' (Trouessart, 1904)
** ''Chaetodactylus nipponicus'' Kurosa, 1987 —host: Osmia cornifrons;
** ''Chaetodactylus osmiae'' (Dufour, 1839) (Previously called ''Trichodactylus osmiae'' Dufour, 1839)
** ''Chaetodactylus panamensis'' Baker, Roubik & Delfinado-Baker, 1987
** ''Chaetodactylus reaumuri'' Oudemans, 1905
* Subgenus Ochaetodactylus Fain, 1981
** ''Chaetodactylus decellei'' Fain, 1974
* Subgenus Spinodactylus Fain, 1981
** ''Chaetodactylus claviger'' Oudemans, 1928
** ''Chaetodactylus krombeini'' Baker, 1962
* Subgenus Achaetodactylus Fain, 1981
** ''Chaetodactylus ceratinae'' Fain, 1976
** ''Chaetodactylus dementjevi'' Zachvatkin, 1941
** Chaetodactylus leleupi Fain, 1974
* Unknown
** ''Chaetodactylus zachvatkini'' Klimov and OConnor, 2008
** ''Chaetodactylus micheneri'' Klimov and OConnor, 2008

References

{{Taxonbar, from=Q4036015

Parasitic acari
Sarcoptiformes
Taxa named by Camillo Rondani