Catania Kenneth C
Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
Brain Behav Evol. 2017;89(4):262-273. doi: 10.1159/000475743. Epub 2017 Jun 27.
When approached by a large, partially submerged conductor, electric eels (Electrophorus electricus) will often defend themselves by leaping from the water to directly shock the threat. Presumably, the conductor is interpreted as an approaching terrestrial or semiaquatic animal. In the course of this defensive behavior, eels first make direct contact with their lower jaw and then rapidly emerge from the water, ascending the conductor while discharging high-voltage volleys. In this study, the equivalent circuit that develops during this behavior was proposed and investigated. First, the electromotive force and internal resistance of four electric eels were determined. These values were then used to estimate the resistance of the water volume between the eel and the conductor by making direct measurements of current with the eel and water in the circuit. The resistance of the return path from the eel's lower jaw to the main body of water was then determined, based on voltage recordings, for each electric eel at the height of the defensive leap. Finally, the addition of a hypothetical target for the leaping defense was considered as part of the circuit. The results suggest the defensive behavior efficiently directs electrical current through the threat, producing an aversive and deterring experience by activating afferents in potential predators.
当遇到大型的、部分浸入水中的导体时，电鳗（Electrophorus electricus）常常会通过跃出水面直接电击威胁源来保护自己。据推测，导体被视作正在靠近的陆生或半水生动物。在这种防御行为过程中，电鳗首先用下颌直接接触，然后迅速跃出水面，在放电的同时沿着导体向上攀爬。在本研究中，提出并研究了这种行为过程中形成的等效电路。首先，测定了4条电鳗的电动势和内阻。然后，通过在电路中让电鳗和水参与，直接测量电流，用这些值来估算电鳗与导体之间水体的电阻。接着，根据电压记录，测定了每条电鳗在防御性跳跃高度时从下颌到水体主体的返回路径的电阻。最后，考虑增加一个用于跳跃防御的假想目标作为电路的一部分。结果表明，这种防御行为能有效地引导电流通过威胁源，通过激活潜在捕食者的传入神经产生厌恶和威慑的体验。
