Effects of testosterone metabolites and estrogen in the midbrain control of courtship behavior in the male ring dove (Streptopelia risoria).

Relative effectiveness of testosterone (T) and its metabolites in the midbrain to induce courtship behavior was investigated in male ring doves. T, 5 alpha-dihydrotestosterone (5 alpha-DHT), 5 beta-dihydrotestosterone, estradiol-17 beta (E), or cholesterol was implanted in or around the nucleus intercollicularis region (ICo) of the castrated male. Resulting courtship behavior was observed by pairing the treated males with stimulus females. T, 5 alpha-DHT and E activated nest-cooling behavior pattern when placed in the ICo region only. Other male courtship behaviors were not induced, induced in each brain region tested or induced by all the hormones. Hormone diffusions from the implant did not appear to be responsible for these results since many implants within 1 mm of the ICo region failed to activate nest-cooling. These data support the idea that the midbrain along with the hypothalamic region mediate male courtship behavior.