Sennertia alfkeni
Fig. 1. Sennertia alfkeni, heteromorphic deutonymph, China, ex Xylocopa appendiculata (BMOC 90-1212-001). Click here to enlarge
Bee Mites : Acari : Acariformes : Sarcoptiformes : Chaetodactylidae : Sennertia

Sennertia alfkeni (Oudemans, 1900)

Trichotarsus alfkeni Oudemans, 1900: 115, Fig. 18-20 (lectotype and 3 paralectotype HDNs in RMNH, designated by Fain, 1974b); Oudemans, 1901: 82 (included in key); Oudemans, 1903a: 147 (included in key, assigned to group D in Trichotarsus);
Trichotarsus Alfkeni: Vitzthum, 1912c: 233 (part., only specimens from X. circumvolans); Vitzthum, 1912d: 290 (comparison with S. horrida)
Trichotarsus japonicus Oudemans, 1900: 117, Fig. 21 (holotype HDN (Japan: Kōbe, ex Xylocopa circumvolans) in RMNH (Fain, 1974b)), synonymized by Zachvatkin (1941), confirmed by Okabe et al., 2008 and Kawazoe at al., 2008; Oudemans, 1901: 83 (included in key); Oudemans, 1903a: 147 (included in key, assigned to group D in Trichotarsus); Trägårdh, 1904: 156 (comparison with S. simplex)
Sennertia alfkeni: Oudemans, 1905a: 22; Sennertia alfkeni: Vitzthum, 1919: 31 (comparison of HDN with S. morstatti, S. horrida); Oudemans, 1924: 329 (comparison with S. sumatrensis); Vitzthum, 1941: 308 (comparison with Sennertia frontalis; species year description given as 1899); Zachvatkin, 1941: 389, Figs 672-644 (Japan, Korea, China, ex Xylocopa circumvolans (as "X. kalinovskii Rad." =Xylocopa kalinowskii Radoszkowski; redescription of HDN, included in key, Sennertia japonica considered as junior synonym of S. alfkeni; species description year given as 1901); Fain, 1974b: 229, Figs. 11-12, 15-16 (redescription of lectotype; species description year given as 1901); Delfinado & Baker, 1976: 85 (comparison with S. americana); Okabe & Makino, 2002: 73, Fig: 5, 6 (SEM pictures, preferred attachment site on host: dorsolateral hairs); Klimov and OConnor, 2008: 222; Okabe et al., 2008: 1361 (description of feeding stages, confirming synonymy with Sennertia japonica based on rearing experiments)
Sennertia japonica: Oudemans, 1905a: 22 (as Tr. japonicus); Vitzthum, 1914: 323 (comparison with HDN of S. morstatti); Vitzthum, 1919: 43 (comparison with S. morstatti and S. horrida, species year description indicated as 1899); Vitzthum, 1941: 308 (comparison with S. frontalis; species year description given as 1899); Okabe & Makino, 2002: 73, Fig: 2a, 3 (color photos in acarinaria), Fig. 4 (ESEM picture; preferred attachment sites: mesosomal and metasomal acarinaria)
Sennertia japonicus: Fain, 1974b: 224, Figs. 5-6 ("species description year given as 1901")
Sennertia ?bifilis: Womersley, 1941: 480, Fig. 17 (Australia: Queensland, ex Xylocopa (Koptortosoma) bryorum (as "Mesotricha bryorum")) (after Fain, 1982)
Sennertia (Sennertia) alfkeni: Fain, 1981a: 163 (redescription of HDN, included in key, subgeneric assignment, assigned to japonica-group, stated that type in RMNH, species description year given as 1901); Fain, 1982: 70 (species description year given as 1901); OConnor, 1993a: 362 (genus-level character acquisition; species description year given as 1901); Kawazoe at al., 2008: 504 (COI sequence data indicate 4 groups corresponding to 4 allopatric hosts, except for mite populations from the northern range of Xylocopa amamensis, which are similar to mites from X. circumvolans)
Sennertia (Sennertia) japonicus: Fain, 1981a: 163 (included in key, subgeneric assignment, assigned to japonica-group; year of species description indicated as 1901)
Trichotarsus Alfkeni: Vitzthum, 1912c: 233, Figs 19-20 (ex Xylocopa (Koptortosoma) aestuans (as Koptorthosoma aestuans) (East Sumatra), Xylocopa (Koptortosoma) caerulea (as Koptorthosoma coerulea) (Java))

Material (show database records).
Biology. This species was known as two separate species Sennertia alfkeni and S. japonica, but it was later shown that these two are genetically the same (Kawazoe et al., 2008) and morphological differences between them are probably continuous and size-dependant (Zachvatkin, 1941; Okabe and Makino, 2008).
Phoretic deutonymphs of the alfkeni-type attach themselves to the dorsoalateral hairs, while those of the japonica-type were common in the mesosomal and metasomal acarinaria of the host. The deutonymphs of both groups display allometric differences. The alfkeni-type deutonymphs are larger (311.8±36.9 μm), with the claw measuring 50.5±8.2 μm, and the ambulacra with a projection, whereas japonica-type deutonymphs are smaller (232.0±18.5 μm), with the claw size 14.7±2.2 μm, and lacking ambulacral projection (Okabe and Makino, 2002; Okabe et al., 2008; Kawazoe et al., 2008). The ambulacral projection found in alfkeni-type deutonymphs apparently aids in the attachment to the host’s hair. In contrast, deutonymphs of the japonica-type do not attach to hairs and are phoretic inside acarinaria, specialized internal structures on the host body serving for mite transfer.
Adults also expressed variation in the form of the dorsal setae, ranging from narrow to broad (Okabe et al., 2008).

Xylocopa (Alloxylocopa) appendiculata Smith, 1852 (=Xylocopa appendiculata circumvolans) (type host).
Xylocopa (Alloxylocopa) amamensis Sonan, 1934
Xylocopa (Alloxylocopa) flavifrons Matsumura, 1912
Xylocopa (Alloxylocopa) albinotum Matsumura, 1926

Distribution (show map). Japan, including Kōbe (type locality), mainland China; "Korea"; Australia (Fain, 1974b; Fain, 1982; Zachvatkin, 1941; Okabe & Makino, 2002; Kawazoe at al., 2008).


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B. OConnor and P. Klimov ©
Created: Jun 09, 2011
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