Shlomi Aharon

I am a Ph.D. student at the National Arachnid Collection, at the Hebrew University of Jerusalem, working on the “Phylogeny, Taxonomy & Ecology of the Spider Genus Tegenaria Latreille, 1804 (Agelenidae) in Israel – a Model for Speciation and Evolution in Caves” advised by Dr. Efrat Gavish-Regev and Dr. Dror Hawlena supported by the Israel Taxonomy Initiative.

The Agelenidae (Koch, 1837) is the 10th species-rich spider family in the world. A taxonomical revision of Israel agelenids by Levy in 1996 reported 19 species. In the past 20 years taxonomical changes have been made in the family in general, and in particular in the Mediterranean genus Tegenaria Latreille, 1804. Tegenaria includes 105 species with many cave-dwelling species; The European Tegenaria was revised by Bolzern in 2013, leaving most of the South-West Asian species un-revised. Recently I discovered un-described species of Tegenaria with reduced eyes from caves in Israel. Caves are excellent field laboratories to study evolution and speciation as they are a unique and isolated underground ecosystem. Limitation of light and resources may act as filters and select for adapted species resulting in many endemics. This research will test whether the origins of the agelenid cave-dwelling fauna of Israel is the result of climatic shifts undergone by this region or of exploitation of new habitat. In addition it will provide new taxonomical knowledge on the Agelenidae of Israel and the Middle East, including a revision of the genus Tegenaria, an updated morphological and molecular phylogeny, a key to the species and descriptions of new troglobitic species found in caves in Israel. .

 .Tegenaria sp

Photo: Shlomi Aharon

 .Tegenaria sp, משפכן מערות עיוור. צילום: שלומי אהרון

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M.Sc.

My M.Sc. was conducted at Ben Gurion University of the Negev, co-advised by  Prof. Yael Lubin, Dr. Efrat Gavish-Regev and Dr. Merav Seifan  and in collaboration with Dr. Bernhard A. Huber (the Alexander Koenig Zoological Research Museum, Bonn, Germany), a world expert for the spider family Pholcidae. The thesis title was “Ecology and taxonomy of the family Pholcidae in Israel: Species richness, geographic distributions and taxonomical revision of the genus Artema (Pholcidae, Araneae)

I conducted a collections-based research on the species diversity and distribution of the pholcid spiders in Israel, together with an arachnid cave survey across Israel, supported by the Israel Taxonomy Initiative and in collaboration with the Cave Research Unit, the Hebrew University of Jerusalem, Israel.

Israel is situated at a biogeographical crossroads, with a mixture of different biogeographical zones. Various geographical features together with diverse climatic conditions result in a unique composition of fauna. However, the diversity of many groups in this region, especially arthropods, remains unknown. The Pholcid spider family is the ninth species-rich family of spiders world-wide, however it is the first time it is studied in Israel.

According to the World Spider Catalog, only five pholcid species are reported from the Levant and only two from Israel thus far. This research examines the species richness and geographical distribution of the pholcid family in Israel, and specifically the taxonomy and the ecology of the genus Artema in Israel.

The collections-based research

The taxonomical revision and the field survey revealed the existence of twelve pholcid species in Israel, including two troglophile species. The first, a species new to science, Artema nephilit sp. nov., is distributed mostly along the Rift Valley. The second species, A. doriai, previously known from Iran only, was found to be rare in the survey. Using statistical models and the data from the cave survey in combination with the physical attributes of the caves and environmental variables, I tested which environmental variables affect the distribution of Artema.

The cave survey

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 conducted a taxonomic survey of arachnids in 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.

This was the first specific survey for arachnids in caves in Israel and except two specimens from Ayalon Cave no true troglobite arachnid were reported from Israel before this survey. However, first findings from a collection-based study and personal observations, indicates a great potential of troglobite species in Israel. This survey aimed 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. Between September 2013 and June 2014 I sampled in more than 40 caves and in crevices in Israel. The survey was conducted in three different seasons: summer, autumn and spring. We collected arachnids by means of pitfall-traps with NaCl solution and hand collecting at caves with different length. In addition we recorded physical and climatic attributes of each cave including temperature (using Temperature Loggers) and luminance. 

In addition, as part of this cave survey we collected for the first time from Israel the troglophile family Leptonetidae, and for the first time from caves in Israel the Afrotropical family Phyxelididae. In addition we found individuals from additional arachnid orders and described recently a species of Amblypygi new to science..

Holocnemus pluchei Scopoli, 1763

Photo: Shlomi Aharon

רעדן

 

Scientific Publications

Aharon S., B.A. Huber, and Gavish-Regev, E., 2017. Daddy-long-leg giants: Revision of the spider genus Artema Walckenaer, 1837 (Araneae, Pholcidae). European Journal of Taxonomy 376: 1-57. DOI: https://doi.org/10.5852/ejt.2017.376

Miranda, G.S.,  Aharon S., Gavish-Regev, E., Giupponi, A.P.L., and G. Wizen, 2016. A new species of Charinus Simon, 1892 (Arachnida: Amblypygi: Charinidae) from Israel and new records of C. ioanniticus (Kritscher, 1959). European Journal of Taxonomy 234: 1-17. DOI: http://dx.doi.org/10.5852/ejt.2016.234

Gavish-Regev, E., Aharon S., Armiach I., and Y. Lubin, 2016. Cave survey yields a new spider family record for Israel. Arachnologische Mitteilungen / Arachnology Letters 51: 39-42. Doi: 105431/aramit5105

Berger-Tal R., Berner-Aharon N., Aharon S., Tuni C., and Lubin Y. 2016. Good reasons to leave home: proximate dispersal cues in a social spider. Journal of Animal Ecology 85: 1035-1042. doi: 10.1111/1365-2656.12534.

Aharon S., Danin A., Al-Shehbaz I., and Greuter W. 2010. Note on Cakile arabica. Med Checklist Notulae, 29 Willdenowia 40: 195-196. doi:https://doi.org/10.3372/wi.40.40205