16 FAUNA OF MAYFIELD'S CAVE. 



There are various sources of organic matter in the cave. Mammals 

 leave excrement and hair and sometimes carry seeds and pieces of trash 

 into the cave; water sweeping into the cave through sink-holes brings 

 protozoans and algae, seeds, stray insects, fish-worms, pieces of wood, 

 and bits of plant stems; and human visitors leave drops of tallow, bits 

 of string, paper, etc. The fungus which grows abundantly upon 

 decaying organic matter in moist portions of the cave apparently serves 

 as food, as well as the decaying organic matter itself. I am reason- 

 ably sure the fungus serves as food to the cave thysanuran at least. 



OPTIMUM CONDITIONS FOR CAVE LIFE. 



Cave animals are most abundant under the following three conditions : 

 (1) A considerable degree of moisture; (2) the presence of decaying 

 organic matter; and (3) the occurrence of loose stones and other debris 

 which serve as places of refuge. The drier parts of the cave, from 

 "21" to about "24," from "26" to "29" and from "33" to "34" are 

 very poor collecting-ground. Leria defessa and L. latens may be seen 

 occasionally, but they are about all. A wet portion of the cave or a 

 moist place caused by water coming through the roof is always favor- 

 able collecting-ground, and particularly so provided the other favorable 

 conditions exist. 



Most species of the cave are scavengers and are attracted to organic 

 matter for food. Bait placed in the cave attracts the beetles (except 

 Anopthalmus) and Aphiochseta, while it brings together Limosina, the 

 myriapods, and thysanurans in great abundance. Any decaying organic 

 matter, whether it is a piece of moldy paper or a drop from a candle, 

 becomes a Mecca for these species. Some of the predaceous species are 

 attracted to the baits also, Phanetta suhterranea and Erigone ivfemalis, 

 for example, but possibly they simply follow up the species upon which 

 they prey. 



As will be mentioned again later, many cave species habitually conceal 

 themselves under something. During the first two trips to Mayfield's 

 Cave I did not learn to turn over debris to look for cave inhabitants and 

 the collections made were very small indeed. Learning to search out 

 the places of concealment, on the third trip I obtained much more 

 material than on the first two trips combined. In parts of the cave 

 where there is considerable moisture, where there is an abundance of 

 decaying organic matter, and where there is debris to serve as places 

 of concealment, conditions of cave life approach the optimum and the 

 abundance of life is really surprising. 



