143 
Appalachian Trechus of the vandykei Group 
Table 4. F-statistics and heterogeneity Chi-square values for four subgroups of 
the Trechus vandykei species group. 
F a 
IT 
F b 
is 
F c 
ST 
2 d 
X 2 
Subgroup 
CAH locus 
bowlingi 
0.670 
0.613 
0.147 
56.825*** 
pisgahensis 
— 
— 
— 
— 
tusquitee 
0.157 
0.033 
0.128 
22.906*** 
vandykei 
0.018 
-0.011 
0.029 
15.747*** 
PGI locus 
bowlingi 
0.199 
0.094 
0.166 
24.153*** 
pisgahensis 
0.184 
0.114 
0.078 
32.506*** 
tusquitee 
0.175 
0.146 
0.034 
6.857** 
vandykei 
0.122 
0.062 
0.065 
104.830*** 
o • 
F - correlation between uniting gametes relative to the gametes of the total 
IT population. 
°F s = average correlation over subdivisions of uniting gametes relative to those 
of their own subdivision. 
p 
F st = correlation of random gametes within subdivisions relative to gametes of 
the total population. 
d ** = P < 0.01; *** = P < 0.005. 
approximately 0.90 or greater for comparisons between local populations 
within subgroups (Table 5). 
Differentiation between subgroups is substantial in some cases. 
Intersubgroup genetic similarities (Table 5) range from values that are 
not very different from infrasubgroup similarities ( haoe vs. vandykei, S 
= 0.921) to values suggesting more distant affinity (pisgahensis vs. 
vandykei, S = 0.776). Clustering of Rogers’ Distance values for the 19 
populations using UPGMA (Sneath and Sokal 1973) produces five 
clearcut groupings (Fig. 2.). The six populations of the pisgahensis 
subgroup form the most distinct cluster. Thus, this subgroup, which 
appears to have lower genetic variability than the other four, is also the 
most biochemically dissimilar of the five subgroups (i.e., S = 0.826 for 
all between-subgroup comparisons). Closer affinities are observed between 
the cluster containing the two tusquitee- subgroup populations and the 
cluster of the four bowlingi populations. The six populations in the 
fourth cluster include all of the populations of the vandykei subgroup, 
