The Journal of Experimental Biology
Killifishes -- Effect of dehydration on, Diapause, Phenotypic plasticity, Oxygen consumption (Physiology)
Annual killifish survive in temporary ponds by producing drought-tolerant embryos that can enter metabolic dormancy (diapause). Survival of dehydration stress is achieved through severe reduction of evaporative water loss. We assessed dehydration stress tolerance in diapausing and developing embryos. We measured oxygen consumption rates under aquatic and aerial conditions to test the hypothesis that there is a trade-off between water retention and oxygen permeability. Diapausing embryos survive dehydrating conditions for over 1.5 years, and post-diapause stages can survive over 100 days. Diapausing embryos respond to dehydration stress by increasing oxygen consumption rates while post-diapause embryos exhibit the same or reduced rates compared to aquatic embryos. Thus, water retention does not always limit oxygen diffusion. Aerial incubation coupled with hypoxia causes some embryos to arrest development. The observed stage-specific responses are consistent with an intrinsic bet-hedging strategy in embryos that would increase developmental variation in a potentially adaptive manner.
© 2020. Published by The Company of Biologists Ltd.
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Published as: Zajic, D. E., Nicholson, J. P., & Podrabsky, J. E. (2020). No water, no problem: Stage-specific metabolic responses to dehydration stress in annual killifish embryos. The Journal of Experimental Biology, jeb.231985. https://doi.org/10.1242/JEB.231985