There are currently 154 species of fleas recorded in Canada in four superfamilies and seven families. Only two species have been added to the list since the previous summary by Holland (1979) one of which is unlikely to be established in Canada. There have been a number of significant nomenclatural changes since then most notable of which is the split of the Hystrichopsyllidae into two families Hystrichopsyllidae and Ctenophthalmidae. An additional 23 species may eventually be recorded based on presence of suitable hosts and proximity to known distributions. Six species are introduced and one species is adventive. Although total diversity is reasonably well known there are numerous gaps in distribution of fleas throughout the country. Barcode Index Numbers are available for only 22 species of fleas collected in Canada.

biodiversity assessment, Biota of Canada, fleas, Siphonaptera

Fleas are a relatively small group, with more than 2200 species known worldwide. Species in Canada range in size from <2 mm (the introduced sticktight flea, Echidnophaga gallinacea (Westwood)) to >9 mm (Hystrichopsylla schefferi Chapin, likely the largest flea in the world). Fleas have profound medical and veterinary significance, and are best known for their role as vectors for the bacterial agent of bubonic plague. Their consequent historic impact on humans and society has been immeasurable. Flea vectors and bubonic plague have been recorded in Canada, and although known to occur in humans, have not been of major concern in recent years. However, the fear of plague epidemics was the stimulus for some of the early work on fleas in western Canada. As a result, our knowledge of the flea fauna of Canada is very good, largely through the efforts of George P. Holland. He produced two monographs (Holland 1949, 1985), the most recent of which included nearly all species recorded for Canada, as well as those for Alaska and Greenland. Today, fleas are mostly regarded as a source of annoyance to humans and to their pets. For example, the introduced cat flea is widespread, and a primary target for pest control in the home.

The following account is for the 154 species known to occur in Canada (Table 1). There have been some nomenclatural changes since Holland (1979, 1985), but only two species, E. gallinacea and Myodopsylla borealis Lewis, have been added to our fauna since that time (Chilton et al. 2000, Galloway et al. 2000). With these exceptions in mind, it is possible to identify the majority of taxa in Canada using Holland’s more recent monograph (Holland 1985). The number of species recorded in Canada represents about 51% of the 303 species found in North America (Lewis and Eckerlin, in press). By far the greatest diversity of species occurs in British Columbia, and more than two thirds of species in Canada are found only in the provinces west of Ontario. There are six species of fleas introduced into North America north of Mexico that have been recorded in Canada (Pulicidae, 3; Leptopsyllidae, 1; Ceratophyllidae, 2), mostly ectoparasites of synanthropic rodents, poultry, and pets. One species of Pulicidae, E. gallinacea, is adventive on migratory birds from the United States and unlikely to become established in Canada.

The higher classification of Lewis (1993a, 1998, 2000) is adopted here. Because of his recognition of the Ctenophthalmidae at the family level, including the Stenoponiinae, Neopsyllinae, Rhadinopsyllinae, Ctenophthalminae, Doratopsyllinae, and Anomiopsyllinae, compared to Holland’s Ctenophthalminae (as part of the Hystrichopsyllidae), the tables here and in Holland (1979) do not compare readily. As well, Holland (1979) cited all taxa, including subspecies, known for Canada as well as for Alaska and Greenland, further complicating comparison of numbers of taxa from 1979 to now. Taxonomic and nomenclatural changes introduced by Smit (1983) in his treatment of the Ceratophyllidae were published too late for Holland to consider and make changes to his 1985 monograph, though these changes were mostly at the generic level and have no effect on numbers of taxa in Holland (1985). There are recent monographs and regional lists of fleas in biogeographic areas outside Canada, where flea species not yet recorded for Canada occur. These include Traub et al. (1983), Lewis et al. (1988), Haas et al. (1989), Lewis (1990), Larson (1997), and Lewis (1998). The papers of RE Lewis (1972, 1973, 1974, 1975, 1993b, Lewis and Lewis 1985) on distribution and host preferences in fleas and on classification of the Siphonaptera are valuable references. As well, Lewis and colleagues published several recent reviews of genera of fleas in North America (Lewis 2000, 2002, 2003, 2008a, b, 2009, Lewis and Galloway 2001, Lewis and Haas 2001, Lewis and Jameson 2002, Lewis and Wilson 2006) wherein there are relevant nomenclatural changes from taxa cited by Holland (1985). In addition, volumes I-V of the Illustrated Catalogue of the Rothschild Collection of Fleas (Hopkins and Rothschild 1953–1971) are essential companions for anyone studying fleas in Canada.

The flea fauna of Canada is relatively well known; it is expected that at least another 23 species may be discovered, more than half of these in the family Ceratophyllidae. These estimates were generated by considering the fauna of adjacent jurisdictions (northern United States, including Alaska) that include species with ranges in close proximity and for which known hosts occur in Canada. I know of no undescribed species of fleas in Canada.

There are enormous gaps in the known ranges of various species across the country. For example, Tarsopsylla octodecimdentatus coloradensis (Baker) is a nest flea of red squirrel, Tamiasciurus hudsonicus (Erxleben), and Kueichenlipsylla atrox (Jordan) is a winter-active flea that infests mustelids. Known records are few and widely scattered. They no doubt occur in many other parts of Canada, but apparent rarity and gaps in distribution are probably the result of insufficient targeted collecting effort. There is also scant information on the seasonal dynamics and life histories of fleas, though there are some recent studies on important aspects of ecology and flea/host interactions (e.g., Reichardt and Galloway 1994, Lindsay and Galloway 1997, 1998, Thomas and Shutler 2001, Perez-Orella and Schulte-Hostedde 2005, Shutler and Campbell 2007, Gorrell and Schulte-Hostedde 2008, Guderham and Schulte-Hostedde 2011, Waterman et al. 2014, Raveh et al. 2015). Larval taxonomy is in its infancy in Canada (but see Elbel 1991, Pilgrim and Galloway 2000, 2007, Galloway and Pilgrim 2001, Harriman et al. 2011). There are extensive or partial larval descriptions for only 16 of the taxa found in Canada, seven of which are for introduced and adventive species.

The Canadian fauna has been poorly characterised using DNA barcodes; there are only about 14% as many BINs as there are described species in Canada, most of which (18 of 22) are from Ceratophyllidae (Table 1). Recent and current studies are focussed on a small number of flea taxa, and there are few broad surveys being undertaken where additional taxa for DNA barcoding could be collected. This represents a significant gap in our knowledge of the fleas of Canada. There are certainly taxonomic problems that could benefit from careful research in which DNA barcoding is a component. For example, there are four species of Ceratophyllus that infest cliff swallows (Petrochelidon pyrrhonota Veillot) in Canada: Ceratophyllus celsus celsus Jordan, C. scopulorum Holland, C. calderwoodi Holland, C. arcuegens Holland. Although their geographic distributions are largely allopatric, there are critical areas of overlap (Galloway 1988). DNA barcoding might be a valuable tool to examine species status among these taxa. It is important that people continue to collect adult fleas and larvae from identified hosts and their nests throughout the country to add to our understanding of this important group of ectoparasites.

Thanks to Wayne Knee and Owen Lonsdale for access to the Canadian National Collection of Insects, Arachnids, and Nematodes database for fleas, and to Jeremy deWaard for his assistance with the BINs for the table. I also thank the Department of Entomology and the Faculty of Agricultural and Food Sciences for their continued support for research on ectoparasites.