| Abstrakt: |
The weakly electric fish, Apteronotus leptorhynchus, produces a wave-like electric organ discharge (EOD) utilized for electrolocation and communication. Both sexes communicate by emitting 'chirps': transient increases in EOD frequency. In males, chirping behavior and the jamming avoidance response (JAR) can be evoked by an artificial EOD stimulus delivered to the water at frequencies 1-10 Hz below the animal's own EOD. In contrast, females rarely chirp in response to this stimulus even though they show consistent JARs. To investigate whether this behavioral difference is hormone dependent, we implanted females with testosterone (T) and monitored their chirping activity over a 5 week period. Our findings indicate that elevations in blood levels of T cause an enhancement of chirping behavior and a lowering of basal EOD frequency in females. Elevated blood levels of T also appear to modulate the quality of chirps produced by hormone treated females. The effects of T on female chirping behavior and basal EOD frequency appear specific, since the magnitude of the JAR was not affected by the hormonal treatment. These findings suggest that seasonal changes in circulating concentrations of T may regulate behavioral changes in female chirping behavior and basal EOD frequency. [ABSTRACT FROM AUTHOR] |
Full text from SpringerLink