1986] Kane & Brunner — Neaphaenops tellkampfi 247 
degree of dependence on the cave environment. Troglobitic species 
such as N. tellkampfi and P. hirtus, which are restricted to subterra- 
nean routes of dispersal, might be expected to show lower gene flow 
levels and greater genetic differentiation than cave dwelling species 
which are still capable of some dispersal on the surface. Although its 
distribution is restricted to cave regions, H. subterraneus emerges 
from caves on warm humid evenings to feed. Thus, the intermediate 
levels of gene flow inferred for H. subterraneus, as opposed to low 
levels for the two troglobites, may result from limited surface dis- 
persal. Morphological evidence (Hubbell and Norton, 1978) also 
suggests a lesser degree of geographic differentiation in H. suberra- 
neus than in N. tellkampfi over approximately the same area. Mor- 
phological differences occur between southwestern populations of 
H. subterraneus (i.e., in the range of N. t. meridionalis ) and those to 
the north. However, there is no significant morphological differen- 
tiation among the northern populations of H. subterraneus (Hub- 
bell and Norton, 1978), whereas in the same region N. tellkampfi is 
morphologically differentiated into three distinct subspecies (i.e., 
henroti, tellkampfi and viator). Trogloxenes show less cave depend- 
ence than troglophiles. Such species often use caves only sporadi- 
cally and only for shelter. Unfortunately no genetic data are 
available for trogloxenes which are partially or wholly sympatric 
with the species described above. Caccone (1985) does report genetic 
data for Euhadenoecus puteanus, a relative of H. subterraneus, 
which is a forest dweller and a sporadic trogloxene over a range 
from southern New York to Georgia. She finds relatively high levels 
of gene flow between five cave populations of E. puteanus which is 
at least consistent with the expectations for a trogloxene. 
Although degree of cave dependence appears to play a major role 
in determining the degree of gene flow and genetic differentiation 
over the geographic range of cave dwelling species, ecological differ- 
ences between species may also influence their genetic characteris- 
tics. Neaphaenops tellkampfi and P. hirtus are both troglobites and 
show similar biogeographic patterns of genetic differentiation. 
However, ecologically the two species are dissimilar. Whereas N. 
tellkampfi is a specialized predator which tends to establish large 
permanent populations (Kane and Ryan, 1983), P. hirtus is more 
opportunistic. Local populations may develop on small isolated 
patches of organic matter such as carrion or feces from reproduc- 
tion by a few founders (Peck, 1973) and such populations are often 
