A Proposal of New Category, Scotophile Visitors, within Trogloxenes in Korean Limestone Caves

Based on the habitats investigation of cave organisms in Korean limestone caves from 1996 to 2005, cave environments can be divided into four zones such as entrance zone, twilight zone and dark zone including unstable Dark Zone with Varying Temperature (DZVT) and stable Dark Zone with Constant Temperature (DZCT). Cave dwelling organisms can be conventionally divided into a troglobite, a troglophile and a trogloxene depending upon the degree of adaptation to dark cave environments, and each life tends to live in its favorable habitat. Detailed investigation of their habitat adaptation patterns for five years in the limestone caves in Korea revealed that troglobites (including stygobites) mostly spend their lifetime in DZCT, however they sometimes migrate to DZVT, but rarely to twilight zone throughout the year. Meanwhile, troglophiles (including stygophiles) spend most of their lifetimes in DZVT, and they tend to migrate to twilight zone or DZCT throughout the year. Among trogloxenes, regular visitors have their own favorable ecological niches to stay in cave. There is also another category of cave organisms that live in twilight zone where organic matter is rich in sediments brought in from the outside. These organisms also tend to migrate to the surface and/or even to DZVT throughout the year. This category of cave organisms tends to be easily found outside and does not seem to be satisfied with stable conditions such as constant temperature and humidity. Therefore, new category may be needed to enlist the habitat patterns of these organisms which were conventionally classified as a trogloxene. Therefore, it is proposed here that new “scotophile” visitors within the category of trogloxenes, should be considered in addition to normal trogloxenes such as bats.