Ecology of Cave Arthropods

Why some species of animals would lose such obviously adaptive characters as eyes and pigmentation to live only in the seemingly inhospitable environ­ ment of caves has long intrigued both laymen and biologists. Evidence that early man recognized cave invertebrates dates back to an engraving of a cave cricket, Troglophilus sp., on a bison bone, discovered in a cave in the French Pyrenees (161), and believed to be 18,000 years old (86). However, serious studies on cave faunas began only about 150 years ago (5, 6). Vandel's monograph (161) provides the most recent overview of the whole science of biospeleology from a worldwide perspective, with an em­ phasis on Europe where most work has been done. Barr provided a thor­ ough review of ecological and evolutionary studies, drawing primarily on work in North America (6). Poulson's review (131) of the ecology and physiology of cave fauna emphasized aquatic species; Poulson & White (139) pointed out the potential for further ecological studies; Ueno (159) reviewed lava tube faunas in Japan; and Reddell (144), the Central Ameri­ can cave faunas. In general, the science of bios pel eo logy in the United States has lagged far behind studies in Europe, and it was not until the 1950s that the modern period of cave biology began in North America (5). The early studies were primarily taxonomic, since detailed ecological and physi­ ological studies require an accurate base of properly identified species. Advances in cave biology have followed the development of cave explora­ tion techniques, and the improvements in the last few decades have allowed biologists to visit and study longer and more complex cave systems in relative safety (e.g. 36, 105). In addition, the increasing ease of world travel has made possible the exploration of the more inaccessible, rugged tropical caves (e.g. see 16, 73, 128).