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The Gefen Lab- Scorpion and Insect Physiology
Current projects
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Gas exchange patterns in insects- Insects exchange respiratory gases with their environment in a variety of patterns, often categorized into continuous, cyclic and discontinuous gas-exchange cycles (DGCs). We are interested in the mechanistic basis and the adaptive value of DGCs.

We both employ a comparative approach and use phase-polyphenism in locusts in order to test predictions of the existing adaptive hypotheses for the evolution of DGCs. Recent findings in our lab suggests that DGCs help conserve water in some grasshopper species, but not in others (Huang et al., 2015). We also selected locusts for desiccation resistance, and showed that DGCs did not contribute to body water conservation in the more resistant selected locusts.

Additionally, we found neural plasticity of ventilatory control, where DGCs require neural output from head ganglia in solitarious, but not gregarious Schistocerca gregaria (Berman et al., 2013).

We are currently investigating the neural basis for variation in gas exchange patterns in grasshoppers.









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Genetic diversity of scorpion populations in Israel- Molecular analyses carried out in the lab confirm previous suspicions  that the two Israeli subspecies of the scorpion Scorpio maurus (Scorpionidae) are distinct species, genetically distinct from the Moroccan subspecies, S. m. mogadorensis, and revealed unexpected genetic diversity in S. m. palmatus. In a study comprising specimens from 40 localities across Israel, we identified seven clades based on mitochondrial and nuclear genes. Despite close geographical proximity, samples of fuscus from Nahal Bohu and palmatus from Nahal Sharsheret in the semi-arid Western Negev area, only 6 km apart, respectively grouped with the other samples of fuscus and palmatus collected as far as 150km away.  Samples of palmatus from the Dead Sea area were genetically divergent from other Israeli palmatus samples, suggesting that palmatus may be a species complex. Interestingly, Golan Heights samples were represented by separate branches, which included both yellow and dark morphs. Our recently published data (Talal et al., 2015) indicate at least four Scorpio species in Israel.

We are currently further studying the
diversity, origins and affinities of the Israeli scorpion fauna in a collaborative project with Prof. Lorenzo Prendini of the American Museum of Natural History.




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