Effects of nostril plugging and of habenulectomy on sexual behaviour in the male crested newt

Abstract

In an attempt to gain some insight into the possible involvement of the habenulae in the control of sexual behaviour in the male crested newt, a comparison was made between the effects of olfactory deprivation by bilateral nostril plugging and of habenulectomy on courtship performance and locomotor activity. Both treatments led to a decrease in spontaneous locomotion and to a drastic abolition of the complex courtship ritual characterized by the sequence of male postures displayed prior to spermatophore deposition. Following nostril plug removal, the animals resumed their normal activities. Unilateral plugging had no effect. These results seem to lend further support to the importance of specific olfactory stimuli in sexual behaviour. The main finding obtained here was the strict comparability between the behavioural changes resulting from habenulectomy and the olfactory-related changes following nostril plugging, linking from a functional point of view the habenulae with the olfactory system. According to recent reports available in the literature, the morphological organization of the habenular nuclei in urodeles still needs further clarification. On the basis of the present results, the possible importance of the habenulae in olfactory integration in the crested newt might be postulated.