Copepod Neurophysiology

Copepod antennule architecture

The implicit assumptions of studying animal behavior are that organisms can discern different signals and that the uniqueness of the signals is the basis for their response. Interpreting mechanosensory behavior of copepods therefore requires an understanding of the characteristics of the fluid signal, the physical coupling and physiological response of the sensor to the fluid signal, and the relationship between the physiology and animal behavior.

Fig. 1. Gaussia princeps. Photograph of the right antennule. Antennule is oriented such that the anterior of the copepod is towards the top of the photo. Setae are identified throughout the site using the numbering scheme shown on this figure.

Fig. 2. Gaussia princeps. Maximum angular displacement of distal seta on the antennule. Letters represent the different durations that the solenoid remained opened; each location is the maximum displacement of the seta at that duration (for scale, width of pipette tip is 150 μm). In both photographs, A represents the seta orientation with no stimulation and when the solenoid remained open for 3 ms; each subsequent letter represents a 2 ms increase in the length of time the solenoid remained open. Left: water jet is aimed at the tip of Seta #8; right: water jet is aimed at Seta #7 (note that when Seta #7 was stimulated in the configuration shown, Setae #6 and #9 did not begin to bend until the solenoid remained open for 7 to 9 ms longer)

Fig 3. Antennule from the male Pleuromamma xiphias. Long hair like structures are mechanoreceptors. Palp-like structures located primarily in the proximal region are chemoreceptors.

SEM of the antennule (Segment 3) of Gaussia princeps.