A REPORT ON INVESTIGATIONS IN THE DENEHOLES 11
although most pieces of wood found in the holes were covered
with the fluffy white mycelia of a fungus, and orange fruiting-
bodies have been noted. Food-cycles independent of microflora
are certainly possible, and depend on the introduction of organic
refuse, and animals from outside, for the support of predators and
refuse-feeders, which live permanently in the dark. The deneholes
are admirably suited to the introduction of food-material produced
external to the holes. Large amounts of vegetable matter, large
numbers of small animals, and occasionally mammals fall into the
holes. The small animals may be attacked by predators or, when
dead, form food for carrion-feeders. Bat excrement is another
possible source of food for the cave fauna, but little excrement
would probably be left by the small number of bats hibernating.
The accidental trogloxenes occurring at the base of the open
shafts are of interest apart from the affect they will have on any
true cave fauna. The species, and the proportion of the different
species occurring at the base of the open shafts, undoubtedly
differ from the proportions entering. Species depending on green
plants, such as Apion dichroum Bedel and the other weevils would
probably not survive for long. The species of beetle found com-
monly on the heaps of debris are detritus and carrion-feeders,
and large predators. The food-cycle at the foot of the open shafts
may be largely closed, and the accidental trogloxenes may con-
tribute little to the food of the true cave fauna.
The following is a complete list of the species so far obtained
from the holes. Nomenclature of the insects is that of Kloet and
Hincks (1945). Species which have been considered by Culling-
ford (1953) as troglophiles, trogloxenes and threshold troglophiles
are indicated by "tp.", "tx.", and "thtp." respectively. An
asterisk (*) indicates species previously unrecorded for Essex, and
all species except those marked ( + ) have only been found within
20 feet of the foot of the open shafts.
MOLLUSCA
PULMONATA
Oxychilus cellarius (Muller) tp.
ARTHROPODA
ISOPODA
Philoscia muscorum Scop.
+ Oniscus asellus L. tx.
Porcellio scaber Lat. tx.
Armadillidium vulgare Lat.
DIPLOPODA
+ Polymicrodon polydesmoides (Leach) tp.
Brachydesmus superus Latzel tp.
*Polydesmus coriaceus Porat tx.
* + Brachyiulus pusillus (Leach)