Olfactory sensitivity for aliphatic alcohols and aldehydes in spider monkeys (Ateles geoffroyi)

Abstract

Using a conditioning paradigm, the olfactory sensitivity of five spider monkeys for homologous series of aliphatic 1-alcohols (1-propanol to 1-octanol) and n-aldehydes (n-butanal to n-nonanal) was investigated. With the exception of 1-propanol, the animals significantly discriminated concentrations below 1 ppm from the odorless solvent, and in several cases, individual monkeys even demonstrated detection thresholds below 10 ppb. The results showed 1) spider monkeys to have a well-developed olfactory sensitivity for both substance classes, which for the majority of alcohols tested matches or even is better than that of the rat, and 2) a significant negative correlation between perceptibility in terms of olfactory detection thresholds and carbon chain length of the alcohols, but not of the aldehydes tested. These findings lend further support to the growing body of evidence suggesting that between-species comparisons of the number of functional olfactory receptor genes or of neuroanatomical features are poor predictors of olfactory performance, and that general labels such as "microsmat" or "macrosmat" (which are usually based on allometric comparisons of olfactory brain structures) are inadequate to describe a species' olfactory capabilities.

Olfactory sensitivity for putrefaction-associated thiols and indols in three species of non-human primate

“…It should be mentioned, however, that these studies employed changes in respiration frequency and heart rate, respectively, to determine olfactory detection thresholds, and both methods are known to be less sensitive than operant conditioning procedures (Hastings, 2003). A within-species comparison between the detection threshold values of the present study with those obtained in earlier studies using the same methods and animals but with other classes of odorants such as aliphatic esters (Hernandez Salazar et al, 2003;Laska and Seibt, 2002a), alcohols (Laska and Seibt, 2002b;Laska et al, 2006a), aldehydes (Laska et al, 2003b;Laska et al, 2006a), ketones (Laska et al, 2005a), carboxylic acids , terpenes (Laska et al, 2006c), thiazoles (Laska et al, 2005b), or steroids (Laska et al, 2005c;Laska et al, 2006b) reveals that in all three species of primate at least one of the putrefaction-associated odorants employed here (indol with squirrel monkeys and pigtail macaques, ethanethiol and 3-methyl indol with the spider monkeys) yielded the lowest detection thresholds among the more than 50 odorants tested so far. This finding is in line with reports showing that human subjects are particularly sensitive to thiols and indols (van Gemert, 2003).…”

“…Corresponding correlations between olfactory sensitivity and length of the carbon chain backbone have also been found in all three species of non-human primate as well as in human subjects for homologous series of esters, alcohols, aldehydes, ketones and carboxylic acids (Laska and Seibt, 2002a;Laska and Seibt, 2002b;Laska et al, 2000;Laska et al, 2003b;Laska et al, 2005a;Laska et al, 2006a;Cometto-Muniz and Cain, 1994). This suggests that this type of correlation might not be restricted to classes of odorants with oxygencontaining functional groups but may represent a more general phenomenon.…”

“…Both views, however, have recently been called into question (Shepherd, 2004;Smith and Bhatnagar, 2004). An increasing number of studies now suggest that the behavioural relevance of odour stimuli rather than neuroanatomical features or the size of the repertoire of olfactory receptors may determine both a species' olfactory sensitivity and its discrimination performance Laska et al, 2003a;Laska et al, 2006a).…”

Brain Connectivity in Ateles geoffroyi: Resting-State Functional Magnetic Resonance Imaging of Working Memory and Executive Control

“…This adaptation of the sensory system speaks to the behavioral importance of olfactory memory for these primates, which is crucial in their natural setting [Fletcher and Henson, 2001;Hernandez Salazar et al, 2003;Laska et al, 2006]. In this respect, we assume that the intense correlation of the amygdala in Ateles is involved in the formation of emotional experiences associated with olfactory as well as auditory and visual memories, since it is crucial to create memories of stimuli that contribute to their survival.…”

“…The memory and other cognitive skills of the spider monkey have been reported to be outstanding under experimental conditions, particularly in relation to its olfactory memory [Hernandez Salazar et al, 2003;Laska et al, 2003Laska et al, , 2006Amici et al, 2008Amici et al, , 2010. For example, Laska et al [2003] conducted a comparative study originally proposed for assessing olfactory performance in an Old World primate, the macaque pigtail.…”