Print
Thysanoptera of Canada
expand article infoRobert G. Foottit, H. Eric L. Maw
‡ Agriculture and Agri-Food Canada, Ottawa, Canada
Open Access

Abstract

The known Canadian Thysanoptera fauna currently consists of 147 species, including 28 non-native species, and there are five additional species found only indoors. DNA barcoding data, presence of species in adjacent regions, and preliminary evidence of the presence of host-associated cryptic species suggest that there may be as many as 255 additional species awaiting discovery or description in Canada.

Keywords

Barcode Index Number (BIN), biodiversity assessment, Biota of Canada, DNA barcodes, thrips, Thysanoptera

The order Thysanoptera (commonly known as ‘thrips’, not to be confused with the genus Thrips) is relatively small, with 6200 species known worldwide (Mound 2018). However, the order is most diverse in the tropical zones where the faunas have received relatively little attention; thus many additional species are expected. About 765 species are recorded in North America north of Mexico (unpublished records for the United States collated by Richard zur Strassen and presented in ThripsWiki 2018, plus 16 additional species in Canada based on specimens in the Canadian National Collections of Insects, Arthropods and Nematodes [CNCI]). The number of species of Thysanoptera known from Canada has increased by about 45% (Table 1) since Heming’s (1979) synopsis. One species of each of two small families, Heterothripidae and Merothripidae, have been detected since then, with an additional family, Melanthripidae, currently represented by an unidentified species of Ankothrips based on a DNA sequence in the Barcode of Life Data System database (www.boldsystems.org).

Census of Thysanoptera in Canada.

Taxon1 No. species reported in Heming (1979) No. species currently known from Canada2 No. BINs3 available for Canadian species Est. no. undescribed or unrecorded species in Canada General distribution by ecozone4 Information sources5
Suborder Terebrantia
Aeolothripidae 13 17 41 30 widespread south of Arctic Chaisson 1986; CNCI, UASM
Heterothripidae 0 1 0 4 Mixedwood Plains Chaisson 1986; CNCI
Thripidae 59 85 (20) 192 120 all ecozones including a few species in the southern Arctic Chaisson 1986; CNCI, UASM, USNM
Merothripidae 0 1 0 0 Mixedwood Plains CNCI
Melanthripidae 0 0 1 0 Pacific Maritime BIOUG
Suborder Tubulifera
Phlaeothripidae 30 43 (8) 104 100 all ecozones except Arctic Chaisson 1986; CNCI, UASM, USNM
Total 102 147 (28) 338 255

Since 1979, there have been several important advances in the knowledge of Canadian thrips diversity. Chasson (1986) made a major contribution to the knowledge of the Canadian fauna, providing keys and descriptions of the genera, and collection data for all species known at that time. She reported 140 identified species, with an additional 42 undetermined or undescribed species, and estimated that 65 more species should occur in this country based on distributions of Thysanoptera in the northern USA. The current total (147 identified established species plus five occurring indoors) is only a marginal increase since Chaisson’s (1986) work.

DNA Barcode Index Numbers (BINs) which give a label to clusters of similar mitochondrial COI sequences (DNA barcodes) correspond approximately to species in many groups (Ratnasingham and Hebert 2013). The relationship between BINs and species concepts has not been critically assessed in Thysanoptera. However, assuming that BIN diversity approximates species diversity (see Ratnasingham and Hebert 2013), derived mainly from untargeted sampling by the Biodiversity Institute of Ontario, University of Guelph, suggests that the number of species sampled could potentially be more than twice the current recognized fauna. There is also preliminary evidence that at least a few species consist of complexes of host-associated lineages (R Foottit and E Maw unpubl. data). Based on the presence of species in adjacent parts of the United States, and on the geographic and taxonomic distribution of unidentified BINs in the DNA barcoding data, we estimate that a further 255 species may eventually be found in Canada (Table 1). However, the Phlaeothripidae, many of which are associated with fungi and decaying wood, are particularly poorly collected, and the estimate of 100 undetected phlaeothripid species in Canada is quite imprecise.

Recent revisions affecting the Canadian fauna have been published for Thrips (Nakahara 1994), for Anaphothrips (Nakahara 1995), and for Chirothrips and related genera (Nakahara and Foottit 2012), including descriptions of new species which occur in Canada (Thrips aurentulus Nakahara, Thrips fallaciosus Nakahara, Thrips intricatus Nakahara, Chirothrips hemingi Nakahara and Foottit).

Most recent literature on Thysanoptera in Canada treats arising economic issues. The eastern species Echinothrips americanus Morgan became a problem in greenhouses in British Columbia (Opit et al. 1997). The non-native Taeniothrips inconsequens (Uzel) was reported as a significant pest on sugar maple (Nystrom and Syme 1994). Old World Frankliniella intonsa (Trybom) has become established in the Fraser Valley of British Columbia (Nakahara and Foottit 2007) and has recently been found in Québec (specimens in CNCI). Drepanothrips reuteri Uzel now occurs on grapes in British Columbia (Lowery 2015). Burgess and Weegar (1988) surveyed the Thysanoptera associated with canola crops in Saskatchewan.

This analysis clearly indicates that the Thysanoptera of Canada are understudied. Much of the non-agricultural regions of the country are only sparsely sampled, and the relative knowledge of species occurring in the various provinces and regions is not uniform. The best known region is the province of Alberta (87 species, or about 60% of the species known to occur in Canada; specimens in the Strickland Museum, University of Alberta and CNCI) due primarily to the efforts of Bruce Heming. There are no recent identification tools available for most groups in the order.

Acknowledgments

We would like to dedicate this work to the late Dr. Bruce Heming (1939-2018), for his contributions to the understanding of Thysanoptera biology and the fauna of Canada. The authors express their thanks to Jeremy deWaard for updates to the number of available Barcode Index Numbers. We thank David Langor and Cory Sheffield for their critical comments.

References

  • Chaisson H (1986) A synopsis of the Thysanoptera (thrips) of Canada. Lyman Entomological Museum and Research Laboratory Memoir No. 17, 153 pp.
  • Langor DW (2019) The diversity of terrestrial arthropods in Canada. In: Langor DW, Sheffield CS (Eds) The Biota of Canada – A Biodiversity Assessment. Part 1: The Terrestrial Arthropods. ZooKeys 819: 9–40. https://doi.org/10.3897/zookeys.819.31947
  • Mound LA (2018) Biodiversity of Thysanoptera. In: Foottit RG, Adler PH (Eds) Insect Biodiversity: Science and Society. Volume II. Wiley Blackwell, Chichester, 483–499. https://doi.org/10.1002/9781118945582.ch18
  • Nakahara S (1994) The genus Thrips Linnaeus (Thysanoptera: Thripidae) of the New World. United States Department of Agriculture, Agricultural Research Service, Technical Bulletin Number 1822, 183 pp.
  • Nakahara S (1995) Review of the Nearctic species of Anaphothrips (Thysanoptera: Thripidae). Insecta Mundi 9: 221–248.
  • Nakahara S, Foottit RG (2007) Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae), an invasive insect in North America. Proceedings of the Entomological Society of Washington 109: 733–734.
  • Nakahara S, Foottit RG (2012) Review of Chirothrips and related genera (Thysanoptera: Thripidae) of the Americas, with descriptions of one new genus and four new species. Zootaxa 3251: 1–29.
  • Nystrom KL, Syme PD (1994) Pear thrips, Taeniothrips inconsequens (Uzel) (Thysanoptera: Thripidae) on sugar maple in Ontario. Proceedings of the Entomological Society of Ontario 125: 19–28.
  • Opit GP, Peterson B, Gillespie DR, Costello RA (1997) The life cycle and management of Echinothrips americanus (Thysanoptera: Thripidae). Journal of the Entomological Society of British Columbia 94: 3–6.