Response properties and biological function of the skate electrosensory system during ontogeny

SUMMARY Elasmobranch fishes (sharks, skates and rays) possess highly sensitive electrosensory systems, which enable them to detect weak electric fields such as those produced by potential prey organisms. Different species have unique electrosensory pore numbers, densities and distributions. Functional differences in detection capabilities resulting from these structural differences are largely unknown. Stingrays and other batoid fishes have eyes positioned on the opposite side of the body from the mouth. Furthermore, they often feed on buried prey, which can be located non-visually using the electrosensory system. In the present study we test functional predictions based on structural differences in three stingray species (Urobatis halleri, Pteroplatytrygon violacea and Myliobatis californica)with differing electrosensory system morphology. We compare detection capabilities based upon behavioral responses to dipole electric signals(5.3–9.6 μA). Species with greater ventral pore numbers and densities were predicted to demonstrate enhanced electrosensory capabilities. Electric field intensities at orientation were similar among these species, although they differed in response type and orientation pathway. Minimum voltage gradients eliciting feeding responses were well below 1 nVcm–1 for all species regardless of pore number and density.

Section: Further Considerationsmentioning

confidence: 69%

Functional consequences of structural differences in stingray sensory systems. Part II: electrosensory system

Jordan

Kajiura

Gordon

2009

“…In Platyrhinoidis triseriata and Raja erinacea, mean rates of PA are 8-18·Hz (New, 1990;Bodznick et al, 2003). Only Raja eglanteria shows PA rates as high as 45·Hz (Sisneros et al, 1998) that are similar to the 44·Hz found in the paddlefish. Spontaneous rates in sturgeons are 20-60·Hz (Teeter et al, 1980) and in catfish 50-100·Hz (Finger, 1986), values comparable to or exceeding the ones in the paddlefish.…”

Section: Discussionmentioning

confidence: 85%

Response properties of electrosensory afferent fibers and secondary brain stem neurons in the paddlefish

Hofmann

Chagnaud

Wilkens

2005

SUMMARY The passive electrosense is used by many aquatic animals to detect weak electric fields from other animals or from geoelectric sources. In contrast to the active electrosense, `passive' means that there are no electric organs,and only external fields are measured. Electroreceptors are distributed in the skin, but are different from other skin senses because they can detect and localize sources a considerable distance away. Distant sources, however,stimulate a large number of receptors at the same time and central circuits have to compute the exact location of the source from this distributed information. In order to gain insights into the algorithms involved, we compared the response properties of units in the dorsal octavolateral nucleus(DON) with primary afferent fibers in the paddlefish. The following parameters were tested: spontaneous activity, sensitivity, frequency tuning, receptive field size, movement sensitivity, and topography within the DON. Although there are some differences in spontaneous activity and receptive field size,there are no major differences between primary afferents and DON units that could reveal any substantial amount of spatial information processing. In particular the lack of any topographic order whithin the DON renders a lateral interaction between neighboring receptive fields unlikely.

“…This sensory capability has been demonstrated to function in the detection and localization of weak bioelectric fields of less than 0.5 nV cm -1 generated by prey (Kalmijn, 1971;Tricas, 1982;Haine et al, 2001;Kajiura and Holland, 2002) and conspecifics (Tricas et al, 1995). It has also been shown to detect the relatively low-frequency electric fields produced by predators (Sisneros et al, 1998), and is theorized to aid in geomagnetic orientation and navigation (Kalmijn, 1974;Paulin, 1995).…”

Section: Introductionmentioning

confidence: 99%

Electroreception in the euryhaline stingray, Dasyatis sabina

McGowan

Kajiura

2009