Family Chaetodactylidae, Bee Mites

Fig. 1. Mite Chaetodactylus krombeini (Chaetodactylidae). Click here to enlarge

Bee Mites : Acari : Acariformes : Sarcoptiformes

Family Chaetodactylidae Zachvatkin, 1941

Trichodactyliens Donnadieu, 1868: 69 (denoting "Trichodactyle Dufour"; as "subsection of Sarcoptides"; nom. preocc. Trichodactylidae H. Milne Edwards, 1853 in Decapoda)
Chaetodactylinae Zachvatkin, 1941: 347 (part., as subfamily of Glycyphagidae). See Klimov and OConnor (2008) for complete synonymy.

General Description. This family includes 5 genera more than 112 species and subspecies distributed worldwide (show map), except for Antarctica (Klimov and OConnor 2008). Chaetodactylids are obligate associates of long-tongued bees and has developed striking morphological, developmental, and biological adaptations to its hosts. The mites live in nests of bees as mutualists (feeding on nest waste), parasitoids (killing the bee egg or larvae), commensals or cleptoparasites (feeding on provisioned pollen) (Krombein 1962, Qu et al. 2002, Roubik 1987). Some parasitoids and cleptoparasites cause substantial damage to managed colonies of mason bees (Osmia) used as commercial pollinators (Bosch 1992, Bosch and Kemp 2001, Fain 1966, Kurosa 1987, Park et al. 2009).
Chaetodactylids disperse as heteromorphic deutonymphs on the adult insects, and the life cycles of the mites and their hosts are usually synchronized. In the Sennertia vaga species group, the deutonymph is probably lost and the mites disperse as feeding instars on adults of large carpenter bees. This group is unusual among astigmatid mites in that reproduction and feeding may occur during dispersal.
At least some species of the genus Chaetodactylus are able to produce morphologically regressive, non-phoretic, heteromorphic deutonymphs. These remain in the nest cavity to infest a new generation of cells when the cavity is re-used.
Most chaetodactylids are oligoxenous, utilizing several closely related hosts and monophyletic groups of mites are often restricted to monophyletic groups of bees, suggesting that they may share common coevolutionary histories. However, historical dispersal of mites to new hosts, most probably, were governed by ecological factors (Klimov et al. 2007a), such as the bee nest architecture. Several bee species of the genera Tetrapedia, Ceratina and Xylocopa have even developed special pouches for mite transfer (acarinaria) (Klimov et al. 2007b), indicating possible mutualistic relationships.
Central and South America, the probable center of origin of the family, are characterized by an exceptional concentration of endemic lineages of mites and their hosts, unfortunately only a few mite species have been described from these regions (Klimov and OConnor 2007).

Diagnosis. The supracoxal sclerites are enlarged and modified. External vertical setae ve are absent or reduced to alveoli in all instars. Tarsal setae aa I, u and v I-IV are absent from all instars. Solenidion ω₃ is shifted to the posterior part of tarsus I in tritonymphs and females (in males it is on the anterior side). In non-deutonymphs, the anterior oblique ridge of the gnathosoma is well-developed, starting near the posterior transverse ridge and extending anteriorly, meeting the internal wall of the palpcoxae. In heteromorphic deutonymphs, supracoxal setae scx are vestigial, with rounded or blunt tips; setae e and ba I-II are absent.

Note. The family-group name is a junior homonym of Chaetodactylini Tschitscherin, 1903 (Coleoptera) (OConnor, 1993).

Genera included

Achaetodactylus Fain, 1981 (=Chaetodactylus (Ochaetodactylus) Fain)
Roubikia OConnor, 1993
Centriacarus Klimov and OConnor, 2007
Chaetodactylus Rondani, 1866
Sennertia Oudemans, 1905

Species included

Click here for species list

ChaetodactylidaeKey to genera of the family Chaetodactylidae of the world
Heteromorphic deutonymphs

Coxal fields III open. Tarsus III with 4 setae (w, r, q, and p absent). Tarsus IV with maximum of 5 setae (s, p, q always absent). Setae 1a and 3a touching posterior borders of respective coxal fields and filiform at least distally. Gnathosomal setae absent. Dorsal setae c₂ distinctly anterior to level of c₁. Condylophores of tarsi I-III well-developed, long and distinctly asymmetrical: anterior longer, posterior shorter or absent (Sennertia argentina, S. donaldi). Worldwide

... 3

Coxal fields III closed. Tarsus III with 7-8 setae (w, r, and p always present). Tarsus IV with 8 setae (s, p, q present). Setae 1a and 3a not touching posterior borders of respective coxal fields, if touching then inflated. Gnathosomal setae present. Setae c₂ on same transverse level as c₁. Condylophores of tarsi I-III short, almost symmetrical. Neotropical, southern Nearctic

... 2

2(1)

Free palpi present. Empodial claws I-III not spirally twisted. Tarsi I-II with 7 setae (p and q present). Tarsus III with 8 setae (q present). Tarsal setae w IV longer than leg IV. Coxal fields IV open. Associated with Centris ... Centriacarus Klimov and OConnor, 2007

Free palpi absent. Empodial claws I-III spirally twisted. Tarsi I-II with 5 setae (p and q absent). Tarsus III with 7 setae (q absent). Tarsal setae w IV distinctly shorter than leg IV. Coxal fields IV closed. Associated with Tetrapedia ... Roubikia OConnor, 1993

3(1)

Transverse medial extension of posterior apodemes IV well-developed. Gnathosomal solenidion absent. Setae se situated on prodorsal shield. Setae e₂ situated on hysterosomal shield. Associated with Afrotropical Ceratina ... Achaetodactylus Fain, 1981 (=Chaetodactylus (Ochaetodactylus) Fain)

Transverse medial extension of posterior apodemes IV absent. Gnathosomal solenidion present. Setae se situated on soft cuticle. Setae e₂ situated outside hysterosomal shield or touching it. Associated with Megachilidae and Apidae. Worldwide

... 4

4(3)

Prodorsal shield and free palpi present. Posterior apodemes II not extending to posteriorly anterior apodemes III. Cupules ih incorporated into lateral sclerotized borders of attachment organ. Solenidion s III absent, represented by alveolus. Solenidion f IV present. Associated with Lithurgini, Osmiini, Megachilini, Anthidiini (Megachilidae), Emphorini, and Tapinotaspidini (Apidae) ... Chaetodactylus Rondani, 1866

Prodorsal shield and free palpi absent. Posterior apodemes II extending posteriorly to anterior apodemes III. Cupules ih situated on sides of attachment organ. Solenidion s III present. Solenidion f IV absent. Associated with Xylocopini and Ceratinini (Apidae) ... Sennertia Oudemans, 1905

Adults
(unknown for Centriacarus and Achaetodactylus)

Anterior paraxial process of cheliceral body developed; fenestrate area fe1 of cheliceral body vertically striated (Fig. 2 B). Solenidion w₂ I proximal to seta d I. Tarsal setae w III, r III-IV, and tibial seta kT IV present. Females. Proximal ends of anterior apodemes I and pregenital sclerite separated. Inseminatory canal cylindrical, well sclerotized, protruding inside spermatheca. Male. Tarsal setae e III-IV absent; p III-IV absent, q III-IV present. Sclerotized portions of condylophores fused and incorporated to the disto-ventral sclerotized tarsal wall, pretarsal suckers not developed (Fig. 3 A). Heteromorphic males present ... Roubikia OConnor

Anterior paraxial process of cheliceral body absent; fenestrate area fe1 of cheliceral body not striated (Fig. 2A). Solenidion w₂ I distal to d I or on same level. Tarsal setae w III, r III-IV, and tibial seta kT IV absent. Female. Proximal ends of anterior apodemes I and pregenital sclerite fused. Inseminatory canal trumpet-shaped or funnel shaped, weakly sclerotized, not protruding inside spermatheca. Male. Tarsal setae e III-IV present; both p and q III-IV absent. Sclerotized portions of condylophores separate, anterior condylophore modified to bilobed pretarsal sucker (Fig. 3 C,D, F,G). Heteromorphic male absent

... 2

2(1)

Female. Proximal ends of anterior apodemes I fused, forming sternum. Male. Main part of progenital sclerites anterior to genital capsule (medial sclerite) (Fig. 4). Progenital sclerites completely fused forming large unpaired sclerite (Fig. 4). Lateral processes (horns) of dorsal supporting sclerite of genitalia with secondary processes (Fig. 5). Tarsi I-IV distinctly thicker than in females, with distinct anterio-dorsal protuberance (Fig. 6). Larva. Claparède's organ present ... Chaetodactylus Rondani

Female. Proximal ends of anterior apodemes I separated from each other by large pregenital sclerite. Male. Main part of progenital sclerites lateral to genital capsule (Fig. 4). Progenital sclerites separate (Fig. 4).. Lateral processes (horns) of dorsal supporting sclerite of genitalia simple or vestigial (Fig. 5). Tarsi I-IV as thick as in females, without distinct anterio-dorsal protuberance (Fig. 6). Larva. Claparède's organ absent ... Sennertia Oudemans

References

Bosch, J. 1992. Parasitism in wild and managed populations of the almond pollinator Osmia cornuta Latr. (Hymenoptera: Megachilidae). Journal of Apicultural Research.31: 77-82.

Bosch, J. & W. P. Kemp. 2001. How to manage the blue orchard bee as an orchard pollinator. Beltsville, MD: Sustainable Agriculture Network. 88 pp.

Donnadieu, A. L. 1868. Sur le genre Trichodactyle. Annales des Sciences Naturelles. 5th Sér. Zoologie et Paléontologie.10: 69-85.

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). Bull. Annls Soc. ent. Belg.102: 249-261.

Klimov, P. B. & B. M. OConnor. 2007. Ancestral area analysis of chaetodactylid mites (Acari: Chaetodactylidae), with description of new early derivative genus and six new species from the Neotropics. Annals of the Entomological Society of America.100: 810-829.

Klimov, P. B. & 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: 243.

Klimov, P. B., B. M. OConnor & L. L. Knowles. 2007a. Museum specimens and phylogenies elucidate ecology' s role in coevolutionary associations between mites and their bee hosts. Evolution.61: 1368-1379.

Klimov, P. B., S. B. Vinson & B. M. OConnor. 2007b. Acarinaria in associations of apid bees and chaetodactylid mites. Invertebrate Systematics.21: 109-136.

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.

Kurosa, K. 1987. Two new Chaetodactylus (Acari, Chaetodactylidae) associated with Osmia (Hymenoptera, Megachilidae) in Japan. Kontyu.55: 373-381.

OConnor, B. M. 1993. Generic relationships in the Chaetodactylidae (Acari: Astigmata) with description of a new genus. Acarologia.34: 345-362

Park, Y.-L., V. Kondo, J. White, T. West, B. McConnell & 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.

Qu, D., Y. Maeta, M. Goubara, K. J. Nakatsuka, J. Kozo & K. Kenji. 2002. Reproductive strategy in the two species of cleptoparasitic astigmatid mites, Chaetodactylus nipponicus and Tortonia sp. (Acari: Chaetodactylidae and Suidasiidae), infesting Osmia cornifrons (Hymenoptera: Megachilidae). I. Invasion/infestation patterns and partial use of the host food. Japanese Journal of Entomology (New Series).5: 121-141.

Roubik, D. W. 1987. Notes on the biology of anthophorid bee Tetrapedia and the mite Chaetodactylus panamensis Baker, Roubik and Delfinado-Baker (Acari: Chaetodactylidae). International Journal of Acarology.13: 75-76.

Zachvatkin, A. A. 1941. Tiroglifoidnue kleshchi Tyroglyphoidea [=Tyroglyphoid mites Tyroglyphoidea]. In Fauna SSSR: Paukoobraznuye, ed. S. A. Zernov, 475. Moscow-Leningrad: Akademiya Nauk SSSR.