Dr. Eran Gefen
Department of Biology and Environment,
Faculty of Natural Sciences,
University of Haifa- Oranim,
Tel: +972 4 9838837
Fax: +972 4 9539608
My area of research is the environmental physiology of animals. More specifically, I am interested in respiratory physiology, water relations and energetics of terrestrial arthropods in the context of evolution of desiccation resistance and tolerance. One of the major physiological challenges resulting from transition to terrestrial life is conserving body water in what is a predominantly dry environment. The small size of arthropods, and thus their relatively high body surface area to volume ratio, further compounds the problem. Still, arthropods are the most successful terrestrial animals in both biomass and diversity, and many arthropod species inhabit some of the hottest and driest habitats on earth.
• Terrestrial arthropods lose water to the environment mainly through cuticular and respiratory transpiration. We are currently studying the potential contribution of gas exchange regulation to the water budget of scorpions under stressful conditions.
• We investigate whether interspecific variation in desiccation resistance in scorpions is correlated with different patterns of metabolic fuel storage, and utilization under stressful conditions.
• We are studying the hydrocarbon composition of the scorpion cuticle. We are interested in interspecific variation and its relation to desiccation resistance. We also investigate whether the cuticular hydrocarbon composition changes during prolonged desiccation in order to increase the integument resistance to water loss.
• Adaptation to local environments could lead to non-random mating between locally adapted and ancestral populations. We are currently studying the adaptive changes that may be involved in reproductive isolation and divergence of desiccation-resistant Drosophila populations.
Refereed papers (* undergraduate co-author):
16. Gefen E. and Brendzel O.* (in press) Desiccation resistance and mating behavior in laboratory populations of Drosophila simulans originating from the opposing slopes of Lower Nahal Oren (Israel). Journal of Evolutionary Biology.
15. Gefen E. (2011). The relative importance of respiratory water loss in scorpions is correlated with species habitat type and activity pattern. Physiological and Biochemical Zoology 84: 68-76.
14. Gefen E. and Gibbs A.G. (2009). Interactions between environmental stress and male mating success may enhance reproductive isolation of stress-resistant Drosophila populations. Evolution 63: 1653-1659.
13. Gefen E., Ung C.* and Gibbs A.G. (2009). Partitioning of transpiratory water loss of the desert scorpion, Hadrurus arizonensis (Iuridae). Journal of Insect Physiology 55: 544:548.
12. Gefen E. (2008). Sexual dimorphism in desiccation responses of the sand scorpion Smeringurus mesaensis (Vaejovidae). Journal of Insect Physiology 54: 798-805.
11. Gefen E., Marlon A.J.* and Gibbs A.G. (2006). Selection for desiccation resistance in adult Drosophila melanogaster affects larval development and metabolite accumulation. Journal of Experimental Biology 209: 3293-3300.
10. Gefen E. and Ar A. (2006). Temperature dependence of water loss rates in scorpions and its effect on the distribution of Buthotus judaicus (Buthidae) in Israel. Comparative Biochemistry and Physiology A 144: 58-62.
9. Haspel G., Gefen E., Ar A., Glusman J.G., and Libersat F. (2005). Parasitoid wasp affects metabolism of cockroach host to favor food preservation for its offspring. Journal of Comparative Physiology A 191: 529-534.
8. Gefen E. and Ar A. (2005). The effect of desiccation on water management and compartmentalisation in scorpions: the hepatopancreas as a water reservoir. Journal of Experimental Biology 208: 1887-1894.
7. Gefen E. and Ar A. (2004). Comparative water relations of four species of scorpions in Israel: evidence for phylogenetic differences. Journal of Experimental Biology 207: 1017-1025.
6. Gefen E., Stone L., Rosenfeld M. and Westernhagen H. (2003). Biological indicators in marine and coastal waters: a statistical and modelling analysis of the MARS campaign. Helgoland Marine Research 57: 272-284.
5. Fishelson L., Bresler V., Abelson A., Stone L., Gefen E., Rosenfeld M. and Mokady O. (2002). The two sides of man-induced changes in littoral marine communities: Eastern Mediterranean and the Red Sea as an example. Science of the Total Environment 296: 139-151.
4. Gefen E. and Ar A. (2001). Morphological description of the developing ostrich embryo: A tool for embryonic age estimation. Israel Journal of Zoology 47: 87-97.
3. Gefen E. and Ar A. (2001). Gas exchange and energy metabolism of the ostrich (Struthio camelus) embryo. Comparative Biochemistry and Physiology A 130: 689-699.
2. Tazawa H., Ar A., Moriya K., Gefen E., and Pearson J. T. (2000). Embryonic heart rate measurements during artificial incubation of emu eggs. British Poultry Science 41: 89-93.
1. Tazawa H., Ar A., Pearson J. T., Moriya K., and Gefen E. (1998). Heart rate in developing ostrich embryos. British Poultry Science 39: 161-166.
Chapters in books:
1. Gibbs A.G. and Gefen. E. (2009). Physiological Adaptation in Laboratory Environments. In: Experimental Evolution (eds. T. Garland and M.R. Rose). University of California Press.
............Dr. Bhawna Kalra (postdoc) .................................Orit Brendzel (M.Sc. student)