1. Mitrani Dept of Desert Ecology; the Jacob Blaustein Inst. for Desert Research, Ben-Gurion Univ. of the Negev; IL-8499000 Midreshet Ben-Gurion Israel
2. Dept of Biology, PO Box 351800; Univ. of Washington; Seattle WA 98195-1800 USA
3. Inst. of Environmental Sciences, Jagiellonian Univ.; PL-30-387 Kraków Poland
4. Inst. of Evolution, Dept of Evolutionary and Environmental Biology; Faculty of Natural Sciences, Univ. of Haifa; 199 Abba Hushi Rd Haifa IL-3498838 Israel