96 
John R. Holsinger and David C. Culver 
entrance, where one would expect food to be more abundant, had 19.6 
prey items with a volume of 0.14 ml per stomach. By contrast 
salamanders from dark zones had only 3.4 prey items with a volume of 
0.05 ml per stomach. 
Diets 
Our knowledge of the diet of cavernicoles is woefully inadequate. 
While food webs are not available for most communities (see Cohen 
1978) and most published food webs are fanciful, the problem is 
particularly acute for cave communities. Packard (1888) pointed out 
nearly a century ago, that “cave animals, even the carnivorous species, 
take remarkably little food.” Contemporary ecological theory predicts 
that a species faced with scarce resources should increase the range of 
foods taken. That is, one would expect little specificity in diet. One 
obvious fact about cave animals is that even their surface relatives tend 
to be omnivorous. 
Many terrestrial cavernicoles feed directly on dead and decaying 
organic matter and associated microorganisms. Except for crickets, 
millipeds are usually the most abundant terrestial cavernicoles. Millipeds 
are frequently found on dead and decaying organic matter, and they 
often ingest rotting wood (Shear 1969). Other invertebrates that feed 
directly on dead and decaying organic matter include staphylinid beetles, 
isopods, and dipterans. Collembolans apparently concentrate on micro- 
fungi (Christiansen 1964b). 
Carnivores are also very catholic in their diets. Around cave 
entrances the orbweb-building spider Meta menardi is often common; it 
captures a variety of flying insects, especially Diptera. Cantharid beetle 
larvae may also be important predators in entrances (Peck 1975b). In 
the dark zones, nesticid and linyphiid spiders construct several small 
sheet webs in which they capture a variety of walking invertebrates. 
Other web-builders are likely to be in the study area — the larvae of the 
fungus gnat Macrocera nobilis (Peck and Russell 1976). These larvae 
build webs in which they catch mostly other dipterans, but they also 
feed on dead organic matter while constructing their webs (Peck and 
Russell 1976). Trechine beetles, which are often common in caves in the 
Interior Low Plateaus, are generally uncommon in Virginia and east 
Tennessee. In common with the small species of Pseudanopthalmus in 
the Interior Low Plateaus, species of this genus in the study area 
probably eat collembolans, small oligochaetes in the mud, diplurans, 
and small diplopods (Barr 1968, Keith 1975, McKinney 1975). Even less 
is known about other invertebrate predators, such as opilionids, 
pseudoscorpions, and rhagidiid mites; but they probably feed mainly on 
Collembola, spider eggs, and small spiders. Finally, the salamanders, 
Eurycea lucifuga and Gyrinophilus prophyriticus eat a wide range of 
invertebrates. 
