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A Checklist of Manitoba Spiders (Araneae)

with notes on geographic relationships

Discussion: Nature of Information on the Spider Fauna of Manitoba

Most intensive spider collecting has been done south of 52N (grids A and B) (Fig. 2), notably in the vicinity of Winnipeg, Riding Mountain National Park, and Taiga Biological Station (5l02'N, 9520'w). Collecting north of 52N includes the collection locations Churchill (5847'N, 94ll'w), Southern Indian Lake (5647'N, 9856'w), and Taiga Biological Station. A total of 1559 grid references were tabulated in the results for the 483 species, an average of 3.2 grid references/species. However, a latitudinal analysis reveals a southern collecting bias, with 885 of the 1559 grid references (57%) in the A and B grids (south of 5 I ON), and 1229 or 79% in the A-C grids, i.e., south of 52N. Hence only 330 or 21 % of the total grid references occur north of 52N, with 151 or 49% of these references for specimens from Southern Indian Lake and Churchill. The largest number of grid references is 237 for A3, which includes the city of Winnipeg (15 % of the total of all grid references for the province). Seventeen grid squares (D4, E3, F5, GI, G4, G5, H3, H5, H6, I1, I2, I3, J1, J2, J3, J5, and K1) have no spider records; these represent more remote and inaccessible areas of Manitoba in the northeast and northwest. We need more collecting there to survey the fauna as a whole. We feel that the species of spiders listed here may represent an estimated 80% of the total for Manitoba. This estimate is based on the total species found in other provinces and on the occurrence of species in adjacent regions and probably to be found in Manitoba with further collecting.

gif: A Grid Map of Manitoba

Figure 2. A grid map of Manitoba, divided by degrees of latitude and longitude defining the labelled squares used to refer to collection localities in the checklist. C = Churchill, SIL = Southern Indian Lake. T = Thompson, TP = The Pas, GR = Grand Rapids, D = Dauphin, TBS = Taiga Biological Station, B = Brandon, and W = Winnipeg.

The biodiversity of species in this province is apparent in a comparison of the provincial land mass (6.5% of Canada) (Payne et al., 1975) with the percentage of the total species within the country; our 483 species represent 37% of the total species in Canada (Dondale, 1979). Likewise we have 20 families, or 59% of those recorded for the country.

In Table 1, we compare Manitoba's spider fauna with that of other Canadian provinces. The Manitoban fauna of 483 species in 20 families compares with British Columbia's 567 species in 28 families (West et al., 1984, 1988), Quebec's 553 species in 19 families (G. Belanger & R. Hutchinson, unpublished data), and Newfoundland's 273 species in 17 families (Hackman, 1954; L. Hollett, unpublished data). If the comparison is based on total species within pairs of provinces, Manitoba shares 253 species (32%) with British Columbia, 371 species (56%) with Quebec, and 203 species (37%) with Newfoundland. We infer that the Manitoba spider fauna is more similar to that of eastern Canada than to that of British Columbia.

Table 1. Numbers of species of spiders from selected geographic regions within Canada (MB=Manitoba, BC=British Columbia, PQ=Quebec, NF=New Foundland)

Family MB BC* PQ** NF***
Uloboridae 1 1 2 0
Dictynidae 21 16 19 7
Amaurobiidae 8 12 7 4
Theridiidae 31 42 46 21
Linyphiidae 51 74 64 46
Erigonidae 128 122 150 91
Araneidae 27 32 29 19
Tetragnathidae 13 9 14 5
Agelenidae 10 29 15 5
Hahniidae 5 6 5 4
Mimetidae 2 2 3 0
Pisauridae 4 1 5 2
Lycosidae 40 46 49 20
Oxyopidae 1 1 0 0
Gnaphosidae 31 46 29 9
Clubionidae 26 23 32 12
Thomisidae 29 32 29 9
Philodromidae 22 28 17 7
Salticidae 33 34 33 10
Other families 0 11 5 2
Total 483 567 553 273
* from West et al., 1984, 1988
** from G. Belanger & R. Hutchinson, unpublished
*** from Hackman, 1954 and L. Hollet, unpublished

Previous Section -- Results: Family Salticidae
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