Report on cave survey supported by the Israel Taxonomy Initiative

Yael Lubin, Efrat Gavish-Regev, Shlomi Aharon, Merav Seifan, Bernhard Huber

We are conducting a collections-based research on species diversity and distribution of pholcid spiders in Israel, and recently we initiated the arachnid cave survey across Israel, supported by the Israel Taxonomy Initiative (ITI) and in collaboration with the Cave Research Unit (CRU), the Hebrew University of Jerusalem (HUJ), Israel.

This research is conducted by the M.Sc. student Shlomi Aharon from Ben-Gurion University (BGU), Israel, under the supervision of Prof. Yael Lubin, Dr. Merav Seifan and Dr. Efrat Gavish-Regev, and in collaboration with Dr. Bernhard A. Huber (the Alexander Koenig Zoological Research Museum (ZFMK), Bonn, Germany), a world expert for the spider family Pholcidae.

Pholcids belongs to the eighth most diverse spider family worldwide, with >1300 described species in 90 genera, and the second largest family of invasive alien spiders in Europe. Yet, it suffers from inadequate research in the Levant in general and in Israel in particular. According to the World Spider Catalog, only six pholcid species are reported from the Levant thus far, with only two species reported from Israel (Pehrforsskalia conopyga Deeleman-Reinhold & van Harten, 2001; Hoplopholcus cecconii Kulczyński, 1908). This low number of species is probably due to inadequate research of this family in the region. Bodenheimer reported two additional cosmopolitan pholcids from "Palestine" in 1935 and 1937: Pholcus phalangioides Fuesslin, 1775 (רעדן), and Artema mauriciana Walckenaer, 1837, while Zonstein and Marusik (2013) in their recent checklist of Israel spiders report a total of five pholcid species from Israel (A. atlanta Walckenaer, 1837; H. cecconii, Holocnemus pluchei (Scopoli, 1763) (מרעידן חום פס), P. conopyga, and P. phalangioides) and one aditional misidentified species (Physocyclus globosus).

Our collections-based research indicates that at least ten pholcid species, belonging to nine genera, have been collected in Israel and deposited in the National Collections of the Hebrew University (HUJ) and of Tel-Aviv University (TAUZM), including the species reported by Zonstein and Marusik (2013). Holocnemus pluchei, is very abundant throughout the country and is a Mediterranean species, while all other species are less common, with two rare species (Pehrforsskalia conopyga; Spermophorides sp.), two cosmopolitan and one non-native species found in buildings and under rocks (Micropholcus fauroti Simon, 1887; Spermophora cf. senoculata  Dugès, 1836; Crossopriza lyioni Simon, 1893), and four species that are restricted to special habitats such as caves and crevices (Artema atlanta; Artema sp.; Hoplopholcus cecconii Kulczyn'ski, 1908; Pholcus phalangioides).

2. First cave survey and main results

On 8-18, September, 2013, we conducted the first excursion together with Dr. Huber (visit supported by TAUZM). We collected spiders from Eilat in the south to Lake Kinneret in the north, mainly along the rift valley, but also in Modi'in and the Mt. Carmel area. We sampled in caves and crevices and near them. We collected a total of 178 (68 live spiders that will be reared to adulthood in the laboratory) spiders belonging to 10 families: 137 Pholcidae; 11 Sicariidae (Loxosceles); 11 Linyphiidae (one male and one female alive); 4 Lycosidae; 4 Filistatidae; 3 Theridiidae; 2 Scytodidae; 1 Uloboridae; 1 Araneidae; 1 Gnaphosidae and 2 unidentified juvenile spiders.

The results of the first survey show that indeed some pholcid species are found in special habitats like caves. This data will be used to build a distribution model of cave pholcids and will be compared with the data from the planned additional cave surveys (March and May 2014).

During October-December, Shlomi Aharon conducted a taxonomical research in the laboratory of Dr. Huber in order to verify the identity of the pholcid species collected on the first cave survey we conducted on September 2013. The results of this survey and the future survey will be published in articles that are currently under preparation, including the description of one new Artema species from Israel, and re-description of the other species in this genus, two of were also found in Israel.

During March and May 2014 we will conduct two additional cave surveys in 35-40 caves of three sizes (small, medium and large) throughout Israel. Half of the caves are ones that we visited in September and half are caves that were not sampled by us (suggested by the CRU and other researchers). We will collect arachnids by hand and using pitfall traps with salt water. In each cave we will measure temperature and light during collection and record using data-loggers the temperatures from March to May. These measurements will be used to prepare the distribution model and list of species in caves.