Timothy C. Tricas

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Arginine vasotocin (AVT) and the homologous arginine vasopressin (AVP) neuropeptides are involved in the control of aggression, spacing behaviour and mating systems in vertebrates, but the function of AVT in the regulation of social behaviour among closely-related fish species needs further clarification. We used immunocytochemical techniques to test(More)
Ampullary electroreceptor systems in fishes and aquatic amphibians are known to function in prey localization by the movement of the animal through a weak dc field produced by their prey. The round stingray produces an electric field with a complex geometry that is modulated rhythmically by movements of the spiracles and gill slits during ventilation. This(More)
Elasmobranch fishes localize weak electric sources at field intensities of <5 ηV cm−1, but the response dynamics of electrosensory primary afferent neurons to near threshold stimuli in situ are not well characterized. Electrosensory primary afferents in the round stingray, Urolophus halleri, have a relatively high discharge rate, a regular discharge pattern(More)
Inertial suction feeding is known to occur in some sharks, but the sequence and temporal kinematics of head and jaw movements have not been defined. We investigated the feeding kinematics of a suction feeding shark, the nurse shark Ginglymostoma cirratum, to test for differences in the timing and magnitude of feeding components with other shark taxa when(More)
Sounds provide important signals for inter- and intraspecific communication in fishes, but few studies examine fish acoustic behavior in the context of coevolution of sound production and hearing ability within a species. This study characterizes the acoustic behavior in a reproductive population of the Hawaiian sergeant fish, Abudefduf abdominalis, and(More)
This study examined the response properties of skate electrosensory primary afferent neurons of pre-hatch embryo (8–11 weeks), post-hatch juvenile (1–8 months), and adult (>2 year) clearnose skates (Raja eglanteria) to determine whether encoding of electrosensory information changes with age, and if the electro-sense is adapted to encode natural bioelectric(More)
The mating season of the Atlantic stingray (Dasyatis sabina), which begins in August and continues through April, is the longest documented for any elasmobranch fish. Despite this protracted mating period, female stingrays ovulate synchronously at the end of the mating season and there is no evidence for sperm storage by females. Thus, the proximate causal(More)
Gonadotropin-releasing hormone (GnRH) and arginine vasotocin (AVT) are critical regulators of reproductive behaviors that exhibit tremendous plasticity, but co-variation in discrete GnRH and AVT neuron populations among sex and season are only partially described in fishes. We used immunocytochemistry to examine sexual and temporal variations in neuron(More)
Sharks and rays are highly sensitive to chemical stimuli in their natural environment but several hypotheses predict that hammerhead sharks, with their expanded head and enlarged olfactory epithelium, have particularly acute olfactory systems. We used the electro-olfactogram (EOG) technique to compare the relative response of the scalloped hammerhead shark(More)
The adaptations of elasmobranch sensory systems can be studied by linking the morphological structure with the natural behavior and ecology of the organism. This paper presents the first step in a ‘neuroecological’ approach to interpret the spatial arrangement of the electrosensory ampullary organs in elasmobranch fishes. A brief review of the structure and(More)