Project Update: Other Scientific Priorities

My husband, Dave Walter, and I are avid acarologists who have worked on the ecology and systematics of mites from soil, water, plants, invertebrates, reptiles, mammals and birds. After spending several years in subtropical and tropical Australia, where almost every mite we came across represented a new species (or genus, or family), we were looking forward to returning to the boreal zone. "We will be able to get back to ecological research", said Dave blithely, "because surely most species in Canada have been described." Hah. Had we read Val Behan-Pelletier’s article in the 2001 Biological Survey newsletter, we would have been better prepared for the taxonomic mysteries presented by terrestrial microarthropods in this country (http://www.biology.ualberta.ca/bsc/news_20_2/soilfauna.htm). The Faunal Analysis Report on mites paints a similar picture, with an estimated 80% of mites in Canada yet to be discovered (http://www.biology.ualberta.ca/bsc/english/acari_old.htm). The hypothetical 7927 unrecorded species are not evenly distributed among mite taxa. Some groups are well known, for example the ticks, Ixodida, with 33 of an estimated 38 species in Canada already recorded. Others have scarcely had their taxonomic surfaces scratched, such as the gall mites (Eriophyoidea), with only 100 of potentially 1000 species known.

Among the lesser known taxa, one ecological group stands out as particularly mysterious: bird mites. This is surprising given the charismatic nature of their habitat. Nevertheless, when one compiles the Faunal Analysis Report’s list of bird-specific taxa (Rhinonyssidae, Syringophilidae, Harpirhynchidae, Turbinoptidae, Freyanoidea, Pterolichoidea Analgoidea), only 21 of an estimated 3275 species are noted as having been reported from birds in Canada. These mites dwell in the respiratory passages, skin, and plumage of their hosts, with the last three superfamilies representing "feather mites" in the strict sense (Gaud and Atyeo 1996) (Fig. 1). When one considers that the above list does not include families that have some but not all members associated with birds (e.g. Macronyssidae, Dermanyssidae, Ereynetidae), there is clearly a huge amount remaining to be discovered about acarine ornithophiles in Canada.

Fig. 1. Male feather mite (Analgoidea: Xolalgidae, Ingrassiella sp.) from the gray catbird, Dumetella carolinenesis. Image by Heather Proctor.

As part of an NSERC Discovery project, I am compiling a list of all reported host-feather mite relationships in published literature. Unlike most of my research, this study actually has some applied value: bird mites can cause serious diseases like scaly-leg in wild birds (Fig. 2) and blood-feeding nest mites are potential agents of West Nile transmission (Fig. 3). Most feather mites, however, appear to be relatively harmless (Proctor 2003). Wheeler and Threlfall (1989) compiled a very useful list of ectoparasites of birds that included most literature records of feather mites in Canada up to the time of publication. Since then, several new records have been published. Based on my literature review there are at least 48 species and 35 genera of feather mites reported from birds in Canada (see Tables 1 and 2). Although this is more than the Faunal Analysis Report’s count of 15 species, it is still a far cry from the 2000 species of feather mites that are expected to occur in this country.

Fig. 2. Grotesquely deformed foot of an evening grosbeak (Coccothraustes vespertinus), and the causal agent, Knemidocoptes sp. cf. intermedius Fain and MacFarlane (Analgoidea: Knemidocoptidae). Image by Wayne Knee and Heather Proctor

Fig. 3. The blood-feeding Dermanyssus quintus Vitzthum (Mesostigmata: Dermanyssidae), from a hairy woodpecker (Picoides villosus). Image by Wayne Knee and Heather Proctor.

How realistic is this predicted number? Another part of my NSERC project, a survey of bird-associated mites from Alberta, may help provide some clues. Compared to other provinces, especially Newfoundland and Manitoba, Alberta has been essentially unexplored with regard to feather mites. Indeed, up to now, only two species of feather mites have been recorded from birds in Alberta (Table 2). Most host specimens for my study have come from the Fish and Wildlife Forensic Lab, with others loaned by the Provincial Museum of Alberta or donated by colleagues who have found window-kills. Each bird’s body is thawed, shaken in a mixture of ethanol, water and dish soap (the ‘martini method’), and the washings poured through a 53 mm sieve. With the help of summer students I have so far extracted mites (and lice) from 112 of the 394 bird species known from Alberta, ranging in size from tiny kinglets and ruby-throated hummingbirds to sandhill cranes and white pelicans (Fig. 4). Although only a small number of these samples have been processed so far, we have recorded representatives of 13 families and 23 genera of feather mites plus Turbinoptidae (considered a ‘feather mite’ by some experts), Epidermoptidae, Knemidocoptidae, Ereynetidae, Harpirhynchidae, Syringophilidae, Trombiculidae, Rhinonyssidae, Dermanyssidae, Laelapidae and Macronyssidae.

Our study parallels research underway at the University of Manitoba by Terry Galloway, who has washed an impressive 213 species of birds with a focus on feather lice. Terry pointed out the scanty knowledge of parasites of birds of Canada several years ago (Galloway and Danks 1990) and is working hard to rectify this. Together, we are collaborating with Sergei Mironov from Zoological Institute of Russia, a renowned feather mite systematist, to identify the Freyanoidea, Pterolichoidea and Analgoidea from Canadian birds. As of June 2004, feather mites from 125 spp. of birds have been identified. They represent 80 genera and 203 species. According to Sergei, 76 of these are species new to science. Extrapolation to the 470 bird species known from Canada (see footnote) implies that a total of 763 feather mite species should inhabit Canadian birds, of which 286 are likely to be new. This does not approach the expected number of 2000 species of feather mites hypothesized in the Faunal Analysis Report; however, one shouldn’t dismiss the higher value as hyperbole. For most bird species we have washed only a few individuals (the modal value is 1). Because it is unusual for an individual bird to carry all mites associated with its species, increasing the number of host specimens washed will likely also increase the number of mite species recorded. Also, there may be geographic differences in feather mite assemblages on the same host such that a cross-country survey of one bird species will result in more mites than concentration on the host species at a single site. Mironov (pers. comm., June 2004) notes that the house martin in the Old World has different mite species at the eastern and western edges of its range, and that the barn swallow in Canada bears a species of Trouessartia that is not represented on this host species in Europe. Likewise, Proctor and Jones (2004) found that different populations of Australian brush turkey hosted different assemblages of mites in northern, central and southern Queensland.

Ultimately, I am interested in what factors determine the diversity of feather mites on different species of birds. Some hosts have no species of feather mites known from them (e.g. penguins), or only one, whereas others have more than 20 species (Proctor 2003). Understanding determinants of diversity is a very long-term goal, in part because the avifauna of several important geographic areas has not been explored, including much of South America and China. I am currently working with Dr. Mauricio Barreto from the University of Valle (Fig. 4) on his huge collection of mites from Colombian birds, and am also involved in an NSF-funded survey of southern Chinese vertebrates and their parasites. These efforts will go some way to filling the gaps in knowledge of global feather mite diversity and host-specificity; however, given the surprisingly large number of new species found from birds sampled from just two provinces in Canada, new material from these tropical areas will likely be overwhelming and require years of dedicated effort from more mite-loving systematists than currently exist. That won’t stop us from trying, though!

Fig. 4. From left, Mauricio Barreto (visiting scientist from Colombia) Heather Proctor, and Wayne Knee (NSERC summer student) with an American white pelican (Pelecanus erythrorhynchos). Image by Michael Pedruski.

References

Atyeo, W.T. and L. Braasch. 1966. The feather mite genus Proctophyllodes (Sarcoptiformes: Proctophyllodidae). Bulletin of the University of Nebraska State Museum 5: 1-354.

Atyeo, W.T. and J.R. Philips. 1984. The feather mite genus Neopetitota (Pterolichoidea: Kramerellidae). Journal of Medical Entomology 21: 409-411.

Banks, N. 1905. A treatise on the Acarina, or mites. Proceedings of the U.S. Natural Museum 28: 1-114.

Banks, N. 1909. New Canadian mites. Proceeding of the Entomological Society of Washington 11: 133-143.

Bonnet, A. 1924. Révision des genres Megninia, Mesalges et genres voisins de la sous-famille des sarcoptides plumicoles (Première Partie). Bulletin de la Société zoologique de France 49: 146-188.

Bourgeois, C. E. and W. Threlfall. 1979. Parasites of the greater shearwater (Puffinus gravis) from Newfoundland, Canada. Canadian Journal of Zoology 57: 1355-1357.

Bourgeois, C.E. and W. Threlfall. 1981. Mallophaga from three species of scoters (Anatidae). Proceedings of the Entomological Society of Washington 83: 799-800.

Boyd, E.M. 1967. Deutonymphs as endoparasites of the eastern belted kingfisher and the eastern green heron in North America. Proceedings of the Entomological Society of Washington 69: 73-81.

Buscher, H.N. 1965. Ectoparasites from anseriform birds in Manitoba. Canadian Journal of Zoology 43: 219-221.

Dabert, J. 2003. The feather mite family Syringobiidae Trouessart, 1896 (Acari, Astigmata, Pterolichoidea). I. Systematics of the family and description of new taxa. Acta Parasitologica 48: S1-S184.

Dabert, J. and R. Ehrnsberger. 1995. Zur Systematik und Phylogenie der Gattung Thecarthra Trouessart, 1896 (Astigmata, Pterolichoidea, Syringobiidae) mit Beschreibung zweier neuer Arten. Mitteilungen, Hamburgisches Zoologisches Museum und Institut 92: 87-116.

Dabert, J. and R. Ehrnsberger. 1999. Systematics of the feather mite genus Montchadskiana Dubinin, 1951 (Pterolichoidea, Pterolichidae, Magimeliinae) with descriptions of five new species. Acta zoologica cracoviensia 42: 219-249.

Galloway, T.D. and H.V. Danks. 1991. Arthropod ectoparasites of vertebrates in Canada. A brief. Bulletin of the Entomological Society of Canada. 23(1), Suppl. 11 pp.

Gaud, J. and W.T. Atyeo. 1996. Feather mites of the world (Acarina, Astigmata): the supraspecific taxa. Musée Royal de l’Afrique Centrale, Annales, Sciences Zoologiques, 277, Pt. 1, 193 pp; Pt. 2. 436 pp.

Hood, D.E. and H.E. Welch. 1980. A seasonal study of the parasites of the red-winged blackbird (Agelaius phoeniceus L.) in Manitoba and Arkansas. Canadian Journal of Zoology 58: 528-537.

McKenzie, C.E. and D.I. MacKenzie. 1981. Comparison of the ectoparasitic fauna of eastern and western kingbirds at Delta Marsh, Manitoba. Canadian Journal of Zoology 59: 717-721.

Miller, M.J.R., P.J. Ewins, and T.D. Galloway. 1997. Records of ectoparasites collected on ospreys from Ontario. Journal of Wildlife Diseases 33: 373-376.

Mironov, S.V. 2000. A review of the feather mite genus Scutomegninia Dubinin, 1951 (Acarina: Analgoidea: Avenzoariidae). Acarina: 8 9-58.

Mironov, S.V. and J. Dabert. 1997. A systematic review of the feather mite genus Bychovskiata Dubinin (Analgoidae: Avenzoariidae) with description of 11 new species. Mitteilungen, Hamburgisches Zoologisches Museum und Institut 94: 91-123.

Mironov, S.V. and T.D. Galloway. 2002. Four new species of feather mites (Acari: Analgoidea). The Canadian Entomologist: 134: 605-618.

Mironov, S.V. and T.D. Galloway. 2003. Two new feather mites (Acari: Astigmata) from the turkey vulture (Ciconiiformes: Cathartidae) in Canada. The Canadian Entomologist 135: 655-667.

Mitchell, W.R. 1953. Observations on poultry diseases in Ontario. Ontario Veterinary College Report 1952: 78-79.

Peterson, P.C. 1971. A revision of the feather mite genus Brephosceles (Proctophyllodidae: Alloptinae). Bulletin of The University of Nebraska State Museum 9: 89-172.

Peterson, P.C., W.T. Atyeo, and W.W. Moss. 1980 The feather mite family Eustathiidae (Acarina: Sarcoptifomes) Academy of Natural Sciences of Philadelphia Monograph 21: 1-143.

Philips, J.R. and A. Fain. 1991. Acarine symbiotes of louseflies (Diptera: Hippoboscidae). Acarologia 32: 377-384.

Proctor H.C. 2003. Feather mites (Acari: Astigmata): ecology, behavior, and evolution. Annual Review of Entomology 48: 185-209.

Proctor, H.C. and D.N. Jones. 2004. Geographical structuring of feather mite assemblages from the Australian brush-turkey (Aves: Megapodiidae). Journal of Parasitology 90: 60-66.

Threlfall, W. and T.A. Wheeler. 1986. Ectoparasites from birds in Newfoundland. Journal of Wildlife Diseases 22: 273-275.

Twinn, C.R. 1935. Records of Mallophaga and other external parasites from birds at Churchill, Manitoba. The Canadian Entomologist 67: 157-159.

Tyrrell, J.B. 1882. On some Canadian ectoparasitic Sarcoptidae. Transcript of the Ottawa Field Naturalist Club 3: 43-48.

Wheeler, T.A. and W. Threlfall. 1986. Observations on the ectoparasites of some Newfoundland passerines (Aves: Passeriformes). Canadian Journal of Zoology 64: 630-636.

Wheeler, T.A. and W. Threlfall. 1989. Synopsis of the parasites of vertebrates of Canada: ectoparasites of birds. M.J. Kennedy (Ed.). Alberta Agriculture, Animal Health Division, Edmonton. 85 pp.

Footnote: Avibase lists 671 as the number of bird species in Canada. However, once extinctions, extirpations, rarities and accidentals are removed, the count is 470 ‘truly’ Canadian birds.

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Volume 23 No. 2, Fall 2004