The telencephalon and hypothalamus of the bluegill (<i>Lepomis macrochirus</i>): Evoked feeding, aggressive and reproductive behavior with representative frontal sections

Abstract

Abstract Bluegills were stimulated electrically while swimming free in an aquarium containing other bluegills, a mirro, gravel and food. Stimulation sites have been plotted on representative frontal sections for which a nomenclature system was developed. Nestbuilding was evoked in both sexes by stimulation near the area dorsalis telencephali pars centralis, while strong after‐responses were elicited from the ventral preoptic region. Stimulation in the preoptic region slightly rostral to the habenula simultaneusly inhibited aggressive behavior and evoked courtship. Feeding (snaping up prey, gravel or debris) and aggressive behavior (chasing and biting another bluegill) resulted from stimulation in the region surrounding the lateral recess of the third ventricle of the inferior lobe of the hypothalamus. In several cases feeding and aggressive responses alternated during stimulation; a similar pattern was observed as an after‐response to stimulation in the nucleus rotundus. These results are discussed with regrard to stimulation in the nucleus rotundus. These results are discussed with regard to possible anatomical systems controlling reproductive, feeding and aggressive behavior in fishes.