Olfactory cues

Beker, R., Dafni, A., Eiskowiteh, D. and Ravid, U. 1989. Volatiles of two chemotypes of Majorana syriaca L. (Labiatae) as olfactory cues for the honeybee. Oecologia 79 446 51. 

Kelche C. and Aron C. (1984). Olfactory cues and accessory olfactory bulb lesion effect on sexual behavior in the cyclic female rat. Physiol Behav 33, 45-48. 

Singh P. and Hofer M. (1978). Oxytocin reinstates maternal olfactory cues for nipple orientation and attachment in rat pups. Physiol Behav 20, 385-389. 

Abstract For most mammals, the ability to detect odours and discriminate between them is necessary for survival. Information regarding the availability of food, the presence of predators and the sex, age and dominance status of conspecifics is odour mediated. Probably because of this extraordinary reliance upon odour cues, mice and rats have developed the ability to learn and remember information associated with olfactory cues as effectively as primates recall visually related cues. As a result, these rodents have become the model of choice to study the neural and cognitive processes involved in olfactory discrimination. In this paper, we describe some of the more ethologically based tasks used in assessing olfactory discrimination and the advantages and disadvantages of the different methodologies employed. 

Claims of commercial manufacturers notwithstanding, it is evident that pheromones do not function as behavioural releasers in humans in the same way as they do in other species. Instead of searching for specific reactions to purported human pheromones, it may be that these chemicals are better described as modulators (Jacob and McClintock 2000) which influence psychological states and, thereby, also influence behaviour in a variety of fashions depending on the situation in which they are experienced, or the accompanying cues. The co-occurrence of different cues can affect their interpretation (Rowe 1999). In humans, we know that odour cues provide non-redundant information about potential mates because, while both visual and olfactory cues may be used to gauge physical attractiveness, the information in each is not equivalent (Roberts, Little, Gosling, Jones, Perrett, Carter and Petrie 2005). 

In mammals, olfactory cues play an important role in sexual selection, both during matechoice and male contests (Andersson 1994) and as olfactory cues are almost always multi-component, they provide a multitude of possibilities to encode information (Albone 1984). Chemical signals may provide information about health (Penn and Potts 1998 Kavaliers, Colwell, Braun and Choleris 2003 Zala, Potts and Penn 2004), dominance status (Gosling and Roberts 2001), sex and group membership (Hofer, East, Sammang and Dehnhard 2001 Safi and Kerth 2003) respectively population affiliation (Hayes, Richardson, Claus and Wyllie 2002). 

Abstract Humans produce temporarily stable, genetically mediated odour signatures and possess the ability to recognise, discriminate and identify other people through the sense of smell. The capability of self, gender, kin and non-kin odour recognition plays a role in social interactions. It seems that despite the stability of olfactory cues, the hedonic quality of body odour may vary over time. 

On the whole, it seems that humans are able to recognize their own body odour and women mostly tend to assess it as pleasant and men mostly as unpleasant. The significant results from experiments dealing with the question of the sexual partner s body odour recognition indicate that humans can learn their partner s olfactory cues, probably through their mutual intimacy. 

Porter, R.H. and Moore, J.D. (1981) Human kin recognition by olfactory cues. Physiol. Behav. 27, 493-495. 

Axillary odour might not be the only olfactory cue to women s reproductive status. Due to the cyclic fluctuations in composition of vaginal secretion one may expect similar changes in vaginal odour. This was demonstrated thirty years ago by Doty, Ford, Preti and Huggins (1975). However, as we have suggested previously, we believe that due to bipedality the axillary odour is of higher importance in humans (Havlicek et al. 2006). 

Current evidence strongly suggests the existence of olfactory cues to ovulation in humans. Such cues could be used by men for monitoring their current or potential partner. It should be noted, however, that men cannot determine ovulation exactly but rather in a probabilistic manner. Therefore we believe that cyclic odour cues are rather a byproduct of physiological changes than a specific signal of ovulation. 

Coopersmith, R. and Leon, M. (1984) Enhanced neural response to familiar olfactory cues. Science 225, 849-851. 

Parrott, M.L., Ward, S.J. and Temple-Smith, P.D. (2007) Olfactory cues, genetic relatedness and female mate choice in the agile antechinus (Antechinus agilis). Behav. Ecol. Sociobiol., DOI 10.1007/s00265-006-0340-8. 

Homing by olfactory cues has been the most researched topic in bird navigation research for many years. Homing pigeons and petrels use airborne cues for orientation under certain conditions. However, many experimental results do not clearly show that odors are the crucial stimuli. 

The two blind mice experiment of Alyan and Jander (1994) used the pup-retrieving behavior of female house mice to determine the visual cues they use for orientation in an arena of Im diameter. A strain of blind mice did not orient as well as intact mice. In different experiments, neither sighted nor blind mice appeared to use olfactory cues such as scent trails in sand, or the odors of wooden blocks in the arena, to find their nest after their arena had been rotated by 90 degrees. Such rotation misled them on their way home, despite landmarks in their arena with odor that should have been familiar to them. We know little on the role of olfactory cues in such short-range orientation. 

Male mice learn about female cues. In the presence of females, a male emits ultrasonic vocalizations. These vocalizations become less frequent after extirpation of the VNO. The more experience a male has had with females, the smaller the deficit he suffers. The learning is mediated by interaction between the main olfactory system and the accessory olfactory system after vomeronasal deprivation, olfactory cues maintain the behavior (Wysocki etal., 1986). 

Some experiments have failed to demonstrate an effect of maternal odors on stressed offspring. The heart rate rose in rat pups removed from their home cage and placed in an unfamiliar environment this was taken as an index of fear. Tests with mothers and soiled bedding from mothers or other rat pups showed that tactile and thermal stimuli reduced fear in 16-day old pups, but olfactory cues from the mother or odors from the home cage did not (Siegel et ah, 1988). 

---