Andrew H . Bass

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An electric fish in the African family Mormyridae recognizes members of its own species by "listening" to electric organ discharges, which are species-specific signatures. Reactions of fish in the field and of individual electroreceptors to both normal and modified computer-synthesized discharges emphasize the importance of the waveform (time-domain cues)(More)
The neuropeptide arginine vasotocin (AVT; non-mammals) and its mammalian homologue, arginine vasopressin (AVP) influence a variety of sex-typical and species-specific behaviors, and provide an integrational neural substrate for the dynamic modulation of those behaviors by endocrine and sensory stimuli. Although AVT/AVP behavioral functions and related(More)
Plasma levels of 11-ketotestosterone, 11-beta-OH-testosterone, testosterone, and 17-beta-estradiol were measured in reproductive Porichthys notatus, a teleost fish with two male morphs and alternative reproductive tactics. The two male types had contrasting androgen profiles. 11-Ketotestosterone was the predominant androgen in the Type I male morph which(More)
Hypopomus pinnicaudatus, an electric fish, has a marked sexual dimorphism in its tail filament. Sexually mature males have long, 'feathered' tails as compared with females. The sexual dimorphism emerges when a fish reaches about 110 mm total length. Mature males have larger electrocytes which are more widely spaced and more numerous than those in mature(More)
In one species of vocalizing (sonic) fish, the midshipman (Porichthys notatus), there are two classes of sexually mature males--Types I and II--distinguished by a number of traits including body size, gonad size, and reproductive tactic. The larger Type-I males (unlike Type-II males and females) build nests, guard eggs, and generate several types of(More)
Although teleost fish have higher levels of brain aromatase activity than any other vertebrate group, its function remains speculative, and no study has identified its cellular basis. A previous study determined aromatase activity in a vocal fish, the plainfin midshipman (Porichthys notatus), and found highest levels in the telencephalon and lower levels in(More)
The present study investigated the relationship between plasma steroid hormone levels and the expression ofpaternal behavior in the plainfin midshipman fish (Porichthys notatus), where males may simultaneously care for multiple clutches in different stages of development. Blood samples were collected from free-living parental males during that part of the(More)
The midshipman fish, Porichthys notatus, generates acoustic signals for intraspecific communication. Nesting males produce long-duration “hums” which attract gravid females and can be effectively mimicked by pure tones. In this study we examine the encoding of tonal signals by the midshipman peripheral auditory system. Single-unit recordings were made from(More)
Evolutionary neurobiologists want to know how neuronal properties (or traits) have been modified to subserve adaptive changes in behavioral phenotypes. Homology can provide a conceptual framework to distinguish the separate contributions of phylogenetic factors and current adaptive modifications to extant traits and behaviors. In this essay, a suite of nine(More)
The peptide arginine-vasopressin (mammals) and its evolutionary precursor arginine-vasotocin (non-mammals) modulate reproductive physiology and numerous related social behaviours, as do oxytocin (mammals) and its homologues mesotocin and isotocin (fish). The distributions in the brain and/or the behavioural functions of these peptides often differ between(More)