Meeting Abstract
The metabolic costs of animal communication signals range from trivial to a significant fraction of the animal’s energy budget. Signals with the highest costs are typically intermittent and can be stopped entirely to reduce ongoing metabolic demand. Doing so eliminates the benefits associated with social signaling (e.g., territorial defense, mate attraction) but allows a shift to other beneficial activities such as foraging. When metabolically costly communication signals are coupled to active sensory systems, reducing or ceasing signaling effort to conserve energy also degrades or eliminates sensory performance, potentially interfering with navigation and foraging. This is the case for weakly electric fish that generate high-frequency electric organ discharges (EODs) which serve as both an active sensory signal and a social communication signal. I will present studies addressing adaptations and constraints imposed by these energetic demands in this system. At the organismal level, some species modulate signal amplitude on a circadian rhythm to conserve energy and also regulate signal amplitude on the timescale of days to weeks to reduce energetic demands in response to chronic metabolic stress. These effects arise from two different hormonal factors that modulate the electrical output of the electric organ cells. We also find a suite of cellular and molecular adaptations in the electric organ cells that allow the maintenance of this high-frequency, high-cost signal while also providing mechanisms for signal reduction during periods of acute metabolic stress. Taken as a whole, these findings reveal how energetic constraints and adaptations have shaped the physiology of an active sensory and communication signals at the organismal, cellular, and molecular levels.
