A survey of the arachnid assemblages in caves in Israel

Shlomi Aharon, Yael Lubin, Amos Frumkin, and Efrat Gavish-Regev.
Caves are a unique underground ecosystem isolated from the outside world and home to many exceptional organisms which have adapted to life in the dark. The study of organisms that live in caves, their evolution, ecology, and conservation has great potential, yet there is little knowledge regarding many animal groups, especially invertebrates. We propose below a taxonomic survey of arachnids in dry caves in Israel. One of the most important groups inhabiting subterranean environments are the arachnids. The number of species in each cave varies according to the latitude and biogeographical region. The areas richest in troglobite (obligate cave dwelling and adapted  to  cave  life)  species  are  those  of  temperate  climates,  mainly Mediterranean. Of the 11 orders of Arachnida, nine have subtreranean representatives. In Israel, there are representatives of eight orders of arachnids (Araneae, Scorpiones, Pseudoscorpiones, Acari, Amblypygi, Opiliones, Palpigradi and Solifugae), six of which are known to have cave living or cave associated species. No specific survey for arachnids in caves has yet been done in Israel and except two specimens from Ayalon Cave no true troglobite arachnid were reported from Israel. However, first findings from a collection-based study and personal observations, indicates a great potential of troglobite species in Israel. This proposed survey aims at studying the arachnid assemblages of caves in Israel, habitats that were never surveyed systematically before, and is part of an ongoing study on the Pholcidae (Araneae) family in Israel and of the Cave Research Unit, The Hebrew University of Jerusalem.