Chaetodactylus

Harmfulness rating

HARMFUL | NOT HARMFUL | UNCERTAIN

kleptoparasitic and predatory; feeds on pollen in bee nests and can attack and kill developing bees

Name

Chaetodactylus Rondani, 1866

Taxonomy

Superorder Acariformes » Order Sarcoptiformes » Suborder Oribatida » Infraorder Desmonomata » Hyporder Astigmata » Family Chaetodactylidae » Genus Chaetodactylus

Type species

Trichodactylus osmiae Dufour, 1839

Common synonyms

Trichodactylus, Tricho tarsustarsus:
Terminal segment (also known as podomere or palpomere) of legs or palps. In Parasitoformes it can be subdivided into telotarsus and basitarsus.

Common names

hairy-footed mites, pollen mites

Diagnosis

Phoretic deutonymphphoretic deutonymph:
An active nymphal stage in Astigmata that serves for dispersal on arthropod or vertebrate hosts. A subtype of heteromorphic deutonymph. See Life stages page for more details.
: Gnathosomal solenidionsolenidion:
Thin-walled, terminally rounded or pointed filiform or peglike structure that is not birefringent in polarized light (unlike common setae in Acariformes). Often appears striated because of its internal structure. Found on the palpal tarsus on the gnathosoma and may also occur on the tarsus and tibia, less frequently on the genu, and occasionally on the femur of legs I-IV. In Acariformes, leg solenidia often arise from unsclerotized areas.
present, setae on free palpi absent, and free palpi present (Fig. 13).

Immobile deutonymphimmobile deutonymph:
Also known as non-phoretic deutonymph. Applies to Astigmata only. Nymphal stage that serves for survival in severe conditions. Morphology regressive, cyst-like; mouthparts, legs, and attachment organ severely reduced and non-functional.
: present (Fig 4)

Female: Sternum present and fused to epigynum (=progenital scleritesclerite:
A component section of an exoskeleton; a plate forming the skeleton of an arthropod.
, i.e., unpaired scleritesclerite:
A component section of an exoskeleton; a plate forming the skeleton of an arthropod.
situated anterior to the oviporus) (Fig. 6).

Homeomorphic male: Progenital scleritesprogenital sclerite:
A paired or unpaired sclerite situated anterior to the oviporus (female) or genital apparatus (male). In some astigmatid females it is a single, enlarged sclerite, which is often called an epigynum in descriprive works. 
completely fused, forming large unpaired scleritesclerite:
A component section of an exoskeleton; a plate forming the skeleton of an arthropod.
(Fig. 14). Lateral processes (horns) of dorsal supporting scleritesclerite:
A component section of an exoskeleton; a plate forming the skeleton of an arthropod.
with secondary processes (Fig. 14). Distinct anterodorsal protuberance on tarsitarsus:
Terminal segment (also known as podomere or palpomere) of legs or palps. In Parasitoformes it can be subdivided into telotarsus and basitarsus.
I-IV present (Fig. 15).

Heteromorphic male: absent

Species identification

A dichotomous key to phoretic deutonymphsphoretic deutonymph:
An active nymphal stage in Astigmata that serves for dispersal on arthropod or vertebrate hosts. A subtype of heteromorphic deutonymph. See Life stages page for more details.
, males, and females is available from the bee-associated mites website and Klimov and OConnor, 2008Klimov and OConnor, 2008:
Klimov, P. B. amp; B. M. OConnor. 2008. Morphology, evolution, and host associations of bee-associated mites of the family Chaetodactylidae (Acari: Astigmata), with a monographic revision of North American taxa. Miscellaneous Publications Museum of Zoology University of Michigan.199: 1-243..

Distribution

Worldwide (except Antarctica)

Bee hosts

family Megachilidae: tribes Lithurgini (Lithurgus, Trichothurgus, and Microthurge), Osmiini (Osmia, Hoplitis, and Chelostoma), Anthidiini (Rhodanthidium and Anthidium), and Megachilini (Megachile)

family Apidae: tribes Emphorini (Melitoma, Diadasia, Ptilothrix, and Ancyloscelis), and Tapinotaspidini (Chalepogenus)

Most species occur on Osmia and Lithurgus, while only a single species is associated with each of the remaining host genera.

Host association level

permanentpermanent:
associated exclusively with bees or their close relative, wasps; cannot live without these hosts

Host associations, feeding, and dispersal

• Feeding stages live in bee nests (Fig. 18). They are mostly kleptoparasitic, but they may kill developing bee larvae via direct attack.
• Phoretic deutonymphsphoretic deutonymph:
  An active nymphal stage in Astigmata that serves for dispersal on arthropod or vertebrate hosts. A subtype of heteromorphic deutonymph. See Life stages page for more details.
  (non-feeding stage) disperse from one nest to another on adult bees (Figs. 16, 17). 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 deutonymphsnon-phoretic deutonymph:
  See immobile deutonymph.
  (non-feeding stage) can survive in the nest cavity to infest new bee generations, if the same nest is reused.

Biology

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 deutonymphsphoretic deutonymph:
An active nymphal stage in Astigmata that serves for dispersal on arthropod or vertebrate hosts. A subtype of heteromorphic deutonymph. See Life stages page for more details.
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 USA, Ch. krombeini phoretic deutonymphsphoretic deutonymph:
An active nymphal stage in Astigmata that serves for dispersal on arthropod or vertebrate hosts. A subtype of heteromorphic deutonymph. See Life stages page for more details.
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 (Park et al., 2009Park et al., 2009:
Park, Y.-L., V. Kondo, J. White, T. West, B. McConnell amp; T. McCutcheon. 2009. Nest-to-nest dispersal of Chaetodactylus krombeini (Acari, Chaetodactylidae) associated with Osmia cornifrons (Hym., Megachilidae). Journal of Applied Entomology.133: 174-180.).

The presence of the inert non-phoretic deutonymphnon-phoretic deutonymph:
See immobile deutonymph.
along with the phoretic deutonymphphoretic deutonymph:
An active nymphal stage in Astigmata that serves for dispersal on arthropod or vertebrate hosts. A subtype of heteromorphic deutonymph. See Life stages page for more details.
is the most conspicuous feature in the life-cycle of this genus. The inert deutonymphdeutonymph:
Ontogenetic stage between protonymph and tritonymph (or adult, if tritonymph is absent).  See Life stages page for more details.
is a highly regressive, cyst-like morph with legs and most setae greatly reduced (Fig. 4). 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 deutonymphsdeutonymph:
Ontogenetic stage between protonymph and tritonymph (or adult, if tritonymph is absent).  See Life stages page for more details.
can be very important for mite survival.

Biology has been studied for Chaetodactylus osmiae (Chmielewski, 1993Chmielewski, 1993:
Chmielewski, W. 1993. Biologia Chaetodactylus osmiae (Duf., 1866) (Acarida, Chaetodactylidae - pylkozernego rozkruszka foretycznie zwiazanego z pszczolami samotnymi (Apoidea). Pszczelnicze Zeszyty Naukowe . 37 : 133-143.; Fain, 1966Fain, 1966:
Fain, A. 1966. Notes sur la biologie des acariens du genre Chaetodactylus et en particulier de C. osmiae , parasite des abeilles solitaires Osmia rufa et O. cornuta en Belgique (Sarcoptiformes: Chaetodactylidae). Bulletin et Annales de la Societe Royale d'Entomologie de Belgique . 102: 249-261.; Lith, 1957Lith, 1957:
Lith, J. P. v. 1957. On the behaviour of Chaetodactylus mites (Acar., Tyr.) in the nests of Osmia rufa L. and Chelostoma florisomne (L.) (Apidae, Megachilidae). Entomologische Berichten . 17: 197-198.; Popovici-Baznosanu, 1913Popovici-Baznosanu, 1913:
Popovici-Baznosanu, A. 1913. Etude biologique sur l'acarien Trichotarsus osmiae Duf. Archives de Zoologie Expérimentale et Générale, Paris. 52: 32-41.), Ch. birulai (Lith, 1957Lith, 1957:
Lith, J. P. v. 1957. On the behaviour of Chaetodactylus mites (Acar., Tyr.) in the nests of Osmia rufa L. and Chelostoma florisomne (L.) (Apidae, Megachilidae). Entomologische Berichten . 17: 197-198.), and Ch. krombeini (Krombein, 1962Krombein, 1962:
Krombein, K. V. 1962. Natural history of Plummers Island, Maryland. XVI. Biological Notes on Chaetodactylus krombeini Baker, a parasitic mite of the megachilid bee, Osmia (Osmia) lignaria Say (Acarina, Chaetodactylidae). Proceedings of the Biological Society of Washington . 75 : 237-250., 1967).