Behavioral and electrophysiological responses of female mice to male urine odors

Female discrimination of male dominance by urine odor cues in hamsters

Female hamsters have been found to differentially respond to the odors of dominant as opposed to subordinate males. This study reexamined these responses in an olfactometer allowing the females to choose between urinary odors obtained from males differing in dominance status and clean air source. The behavior of the estrous females was consistent with previous research which indicated that such females exhibit a preference for stimuli obtained from dominant males. Contrary to previous findings in a two-choice apparatus, diestrous females failed to prefer the odors of subordinates. These females spent significantly more time in the area infused with unscented air. These data emphasize the importance of odor cues as they relate to male attractivity and possibly mate choice. They also underscore the need to allow animals to avoid conspecific odors in order to reduce the possibility of forcing animals into an unrealistic choice situation.

Responses to conspecifics' urine by the degu (Octodon degus)

In nature the degu has been observed to deposit and to investigate scents. This study employed a captive group of these animals to investigate their responses to conspecific urinary marks in a neutral arena. Both sex classes served as subjects. They were presented with urine obtained from males, from females and a saline control. The females were found to be more active in responding. On the basis of sniffing frequency, they exhibited greater discriminative abilities than did the males. The urine from female donors was sniffed more frequently by all subjects. The frequency of approaching a mark and the time spent in the vicinity of a stimulus are interpreted as being investigatory responses. It seems that the marks deposited by females have a greater salience and that females are more sensitive to olfactory stimuli.

Identification of a testosterone-dependent unique volatile constituent of male mouse urine: 7-exo-ethyl-5-methyl-6,8-dioxabicyclo[3.2.1]-3-octene

Investigations regarding the chemical composition of the volatiles in male mouse urine have recently enabled the structural elucidation of a hitherto unreported urinary component, 7-exo-ethyl-5-methyl-6,8-dioxabicyclo[3.2.1]-3-octene. This compound's uniqueness to mouse urine and its dependence on testosterone levels in the male suggest its probable role as a mouse pheromone or pheromone adjuvant.

Effects of insulin injection on responses of olfactory bulb and amygdala single units to odors

The effect of insulin injection on transmission of neural activity within the olfactory system of the anesthetized male rat was investigated at the single unit level. It was found that insulin changed the response to odors of approximately 27% of olfactory bulb units and 21% of amygdala units tested. Many of the changes were in the direction of an increase in response magnitude, but there were some reversals in response direction and other complex changes. There was no evidence of a selective facilitation of responses to food odor as compared to non-food odors. Control observations of the response of thalamic somatosensory units to tactual stimulation showed no effects of insulin. These results suggest that hypothalamic hunger mechanisms may normally interact with olfactory mechanisms to augment and otherwise change the response of some olfactory system units to various odors.

Social olfaction: a review of the role of olfaction in a variety of animal behaviors

Behavioral olfactory experiments were reviewed, relating the behavioral effects of pheromones to the psychophysical work in olfaction. Short descriptions of various experiments were used to show the importance of olfaction to the social behavior of animals by tracing the history of the experimental evidence and viewing the behavioral data pertaining to the discharge of pheromones and their effects and to look at the psychophysical evidence for olfactory acuity and the behavioral implications for the role of the physiological structures in olfaction.