Hilchie 1982 QEv18n1_4 91_126 CC released.pdf - College of ...

Philanthus albopilosus Cresson 115
Figure 6. Typical and maculated specimens of female Philanthus albopilosus (northern race). Figures 6a, 6b, and 6d,
head, thorax and abdomen of a dark specimen from Empress, Alberta. Figure 6c, head of maculate specimen of the dark
race at Medicine Hat, Alberta.
Males of P. albopilosus also exhibit some trends in colouration (Figure 5) but these are not
as distinctive. Individuals from northern populations (Areas 7 to 12) tended to be darker
(Figure 8). Males from southern and western areas (Areas 1 to 6) tended to be pale. There is
not a discrete break in index values but a trend to shift to darker forms in the northeast and
lighter forms in the southwest.
Index values for each area were averaged, female index values were plotted against male
index values (Figure 9). The points form loose clusters: northern groups separate together, in
contrast to southwestern populations and geographically intermediate populations. The points
illustrate a break in variation, with the largest break occurring between the geographically
intermediate group and the northern group. The phenotypically intermediate groups are the
extreme southwestern populations which may grade into the geographically intermediate
group.