Abstract
Using operant conditioning procedures, we assessed the olfactory sensitivity of six CD-1 mice and three spider monkeys for mold-associated odorants. We found that with all eight stimuli, the mice detected concentrations as low as 0.1 ppm (parts per million), and with two of them individual animals even detected concentrations as low as 1 ppt (parts per trillion). The spider monkeys detected concentrations as low as 4 ppm with all eight stimuli, and with four of them individual animals even detected concentrations as low as 4 ppb (parts per billion). Between-species comparisons showed that with all eight odorants, the mice displayed significantly lower threshold values, that is, a higher sensitivity than the spider monkeys, but not than human subjects tested in previous studies. Analysis of odor structure–activity relationships showed that in both species, the type of oxygen-containing functional group and the presence versus absence of a double bond as well as the length of the carbon backbone of the odor stimuli had a systematic effect on detectability. We conclude that both mice and spider monkeys are clearly able to detect the presence of molds and thus to assess the palatability of potential food using the volatiles produced by molds during putrefaction.
Highlights
Food selection is the process by which animals try to optimize their energy yield, to meet their nutrient requirements, and to avoid ingestion of potentially harmful substances (Stephens and Krebs 1986)
The quantitatively predominant mold-associated odorants found in the headspace above fungal species such as Aspergillus, Penicillium, and Fusarium include, but are not restricted to, branched and/or unsaturated aliphatic ketones and alcohols (Börjesson et al 1992; Schnürer et al 1999; Li et al 2016)
The rationale for choosing spider monkeys was that data on olfactory detection thresholds for homologous series of aliphatic aldehydes (Laska et al 2006b, c), carboxylic acids (Laska et al 2004; Güven and Laska 2012), and ketones (Eliasson et al 2015; Laska 2014), as well as for structurally related aromatic aldehydes (Larsson and Laska 2011; Kjeldmand et al 2011), alkylpyrazines (Laska et al 2009), monoterpenes (Joshi et al 2006), “green” odors (Løtvedt et al 2012), amino acids (Wallén et al 2012), and sulfurcontaining predator odorants (Sarrafchi et al 2013) were obtained in earlier studies with both species, allowing for direct between-species comparisons of olfactory sensitivity
Summary
Food selection is the process by which animals try to optimize their energy yield, to meet their nutrient requirements, and to avoid ingestion of potentially harmful substances (Stephens and Krebs 1986). The vast majority of terrestrial mammal species rely on, or at least include, their sense of smell for food selection (Stoddart 1980; Hughes 1990). This should not be surprising given that fruits, for example, systematically change their odor in the course of maturation and provide an honest chemical signal of their nutritional value (Goff and Klee 2006; Nevo and Valenta 2018). The quantitatively predominant mold-associated odorants found in the headspace above fungal species such as Aspergillus, Penicillium, and Fusarium include, but are not restricted to, branched and/or unsaturated aliphatic ketones and alcohols (Börjesson et al 1992; Schnürer et al 1999; Li et al 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
