Abstract
Dose-response characteristics were evaluated for two groups (I and II) of pheromonesensitive neurones in the antennal lobes of the brain of adult male Periplaneta americana. Group I neurones react with about equal sensitivity to periplanone A and periplanone B, two major components of the female sexual attractant. Group II neurones are much less sensitive to B than is group I, but A is similarly effective with this group. Each group reveals a specific innervation pattern of the sex-specific macroglomerulus in the olfactory neuropile of the deutocerebrum.