Aggressive display in female Betta splendens as a function of norepinephrine treatment and social experience

Abstract

The present experiment was designed to ascertain the influence of treatment with norepinephrine on the aggressive display (AD) behavior of female Betta splendens. Male-female and female-female pairs were constructed in which either both, one, or neither pair-mate was treated with norepinephrine. A single treatment with norepinephrine was found to increase AD behavior after 12 hours without exogenous norepinephrine present in the testing situation. Some evidence was found for drug induced efforts lasting over 10 days of pairing. Group means for gill cover extension (GCE) tended to occur in the following decreasing order of magnitude, both treated, one treated, neither treated. Males were found to be dominant over females, but treated females emitted substantial AD in the presence of the males. Results were discussed in terms of stimulus adequacy of treated and untreated Ss, effects of social experience, the physiological mechanisms mediating the drug effect, and the differentiation of mechanisms responsible for the drug effect.