The freshwater paddlefish Polyodon spathula (Polyodontidae) feeds primarily on the water flea (Daphnia sp.), and previous studies suggest that these fish detect their planktonic prey using their rostral electrosensory system. Zooplankton produce direct-current and oscillating alternating-current electric fields containing multiple frequencies and amplitudes. We asked whether an inanimate electric field is sufficient to elicit paddlefish strikes equivalent to their feeding behavior. Juvenile paddlefish respond to artificial dipole stimuli by investigating the electric field and striking at the dipole electrode tips. These behavioral responses, scored as strikes, exhibit a bandpass characteristic with a maximum response between 5 and 15 Hz. Responses were less frequent at higher (20, 30, 40, 50 Hz) and lower (0.1, 0.5, 1 Hz) test frequencies, with a steep drop-off below 5 Hz. Strike rates also varied with stimulus intensity. Response frequency was greatest at 0.25 microA peak-to-peak amplitude, with reduced responses at lower and higher amplitudes (0.125 and 1.25 microA). Striking behavior was also influenced by water conductivity: strike rate was reduced at higher water conductivity. Dipole-elicited strikes exhibit behavioral plasticity. Fish habituate to repetitive dipole stimuli that are not reinforced by prey capture, and they dishabituate after food reinforcement. These experiments characterize paddlefish feeding strikes towards dipole electrodes at signal frequencies and intensities simulating the electric fields of zooplankton, their natural prey, and demonstrate that electric fields are sufficient to elicit feeding behavior. The results support the conclusion that paddlefish use their passive electrosensory system for planktivorous feeding.
Celebrating 100 years of discovery
We are proud to be celebrating 100 years of discovery in Journal of Experimental Biology. Visit our centenary webpage to find out more about how we are marking this historic milestone.
Craig Franklin launches our centenary celebrations
Editor-in-Chief Craig Franklin reflects on 100 years of JEB and looks forward to our centenary celebrations, including a supplementary special issue, a new early-career researcher interview series and the launch of our latest funding initiatives.
Looking back on the first issue of JEB
Journal of Experimental Biology launched in 1923 as The British Journal of Experimental Biology. As we celebrate our centenary, we look back at that first issue and the zoologists publishing their work in the new journal.
Biology Communication Workshop: Engaging the world in the excitement of research
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We are delighted to be sponsoring a Biology Communication Workshop for early-career researchers as part of JEB’s centenary celebrations. The workshop focuses on how to effectively communicate your science to other researchers and the public and takes place the day before the CSZ annual meeting, on 14 May 2023. Find out more and apply here.
Mexican fruit flies wave for distraction
Dinesh Rao and colleagues have discovered that Mexican fruit flies vanish in a blur in the eyes of predatory spiders when they wave their wings at the arachnids, buying the flies time to make their escape.
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