Consumption of garlic affects hedonic perception of axillary body odour

Beneficial health properties of garlic, as well as its most common adverse effect – distinctive breath odour – are well-known. In contrast, analogous research on the effect of garlic on axillary odour is currently missing. Here, in three studies varying in the amount and nature of garlic provided (raw garlic in study 1 and 2, garlic capsules in study 3), we tested the effect of garlic consumption on the quality of axillary odour. A balanced within-subject experimental design was used. In total, 42 male odour donors were allocated to either a “garlic” or “non-garlic” condition, after which they wore axillary pads for 12h to collect body odour. One week later, the conditions were reversed. Odour samples were then judged for their pleasantness, attractiveness, masculinity and intensity by 82 women. We foundnosignificant differences in ratings of any characteristics in study 1. However, the odour of donors after an increased garlic dosage was assessed as significantly more pleasant, attractive and less intense (study 2), and more attractive and less intense in study 3. Our results indicate that garlic consumption may have positive effects on perceived body odour hedonicity, perhaps due to its health effects (e.g.,antioxidantproperties,antimicrobialactivity)

Effect of biological relatedness on perfume selection for others: Preliminary evidence

People tend to choose perfumes to complement their body odour. As kin share some body odour qualities, their ability to select complementary perfumes for relatives might be higher compared to selection for non-relatives. We tested this in two studies, comparing selection of a perfume for a target man by himself and by either a familiar but unrelated individual (girlfriend; Study 1) or a relative (sister; Study 2). Target men applied the two perfumes (own/other’s choice) to their axillae and then wore cotton pads for 12h. Collected perfume-body odour blends and perfumes alone were assessed by rater panels. In Study 1, the blends were rated as nominally more pleasant when body odours were mixed with the perfumes selected by girlfriends compared to those selected by target men themselves. In Study 2, body odours mixed with perfumes selected by sisters were rated significantly more attractive than those mixed with perfumes selected by target men. No significant differences were found for attractiveness and pleasantness ratings when perfumes were rated alone, suggesting that it was the resulting blends that were uniquely different. Our results indicate that sisters might be particularly tuned to select suitable perfumes for their siblings

Human Body Odour Composites Are Not Perceived More Positively than the Individual Samples

It is well established that composite facial images are perceived as more attractive compared with individual images, suggesting a preference for heterozygosity. Similarly, there is evidence that preferences for body odours might be linked to heterozygosity. Here, we tested whether blending individual body odours into composites would follow a similar pattern as observed in the perception of faces. We collected axillary odour samples from 38 individuals, which were subsequently assessed individually and as composites of two (N=19) or four (N=9) body odours regarding their pleasantness, attractiveness and intensity. We found no significant differences between mean ratings of individual odour samples or composites of two or four odour samples. Our results indicate that, in contrast to faces, composite body odours are not rated as more attractive. Composite body odours retain similar hedonic perceptual qualities as individual odours, thus highlighting differences in visual and chemosensory perceptual mechanisms

Men’s preferences for women’s breast size and shape in four cultures

The morphology of human female breasts typical for their permanent fat deposits appears to be unique among primates. It has been previously suggested that female breast morphology arose as a result of sexual selection. This is supported by evidence showing that women with larger breasts tend to have higher estrogen levels; breast size may therefore serve as an indicator of potential fertility. However, breasts become less firm with age and parity, and breast shape could thus also serve as a marker of residual fertility. Therefore, cross-culturally, males are hypothesized to prefer breast morphology that indicates both high potential and residual fertility. To test this, we performed a survey on men´s preferences for breast morphology in four different cultures (Brazil, Cameroon, the Czech Republic, Namibia). As stimuli, we used two sets of images varying in breast size (marker of potential fertility) and level of breast firmness (marker of residual fertility). Individual preferences for breast size were variable, but the majority of raters preferred medium sized, followed by large sized breasts. In contrast, we found systematic directional preferences for firm breasts across all four samples. This pattern supports the idea that breast morphology may serve as a residual fertility indicator, but offers more limited support for the potential fertility indicator hypothesis. Future studies should focus on a potential interaction between the two parameters, breast size and firmness, which, taken together, may help to explain the relatively large variation in women's breast sizes

Gonadal suppression alters axillary steroid secretions in men, but does that affect olfactory social signaling?

Background and objective: Luteinizing hormone-releasing hormone agonists (LHRHa) suppress gonadal hormone production and are commonly used to treat prostate cancer (PC) in men and conditions ranging from uterine fibroids to estrogen-sensitive cancers in women. They are also used to delay sexual development in children considering gender reassignment or experiencing premature puberty. As chemically castrating agents, LHRHa may affect cutaneous steroid secretions, which, in turn, could alter body odor and influence the psycho-sexual dynamics between individuals. The objectives of the present study were to determine (1) if LHRHa indeed alter cutaneous skin secretions, and (2) whether this leads to perceivable changes in body odor. Material and methods: Axillary skin secretions were collected on new cotton T-shirts worn by men undergoing androgen deprivation therapy with an LHRHa to treat PC (n = 10), both before starting the LHRHa and 3 months later. Healthy heterosexual university students (50 males, 50 females) were recruited to smell and rate the shirts for their masculinity, attractiveness, and intensity of odor. Liquid chromatography-mass spectrometry (LC-MS) was also used to analyze steroids extracted from the shirt samples. Results: LC-MS showed a statistically significant decline in the concentration of the androgenic metabolites, androsterone and 5α-androstane-3,17-dione. This confirms that LHRHa drugs that suppress gonadal hormone production markedly reduce cutaneous secretion of androgenic metabolic intermediates in adult males. However, no differences in odor were detected in the ratings of the shirts by male, female, nor male and female raters combined for any of the three variables assessed. Possible reasons why the human sniffers failed to perceive a change in odor are explored. Conclusion: Our data document that LHRHa alter steroid skin secretions in older men, but whether such changes alter the olfactory signals that might influence psychosocial interactions remains unresolved

Bird Diversity as a Support Decision Tool for Sustainable Management in Temperate Forested Floodplain Landscapes

Sustainably managed forests provide multiple ecosystem services in cultural landscapes, including maintaining biodiversity. Better understanding of the benefits regarding the biodiversity of different silvicultural practices is important for sustainable landscape management. Conservation targets in forested landscapes should be determined by land managers and policy-makers, based on serious ecological research. This study deals with response of bird diversity to three different habitat types of temperate hardwood floodplain forests, which reflect specific forms of forest management. Research was based on long-term field bird census in the years 1998 to 2002 applying the point count method. Data was analysed using regression analysis with dummy variables. The results of the study indicate that hardwood floodplain forest heterogeneity, supported by different types of forest management (old-growth forest protection, group-selection harvesting and forest edge protection), provides large-scale habitat mosaic conditions suitable for many breeding bird species with different ecological niches. This result suggests that comparison of bird diversity response to different forest management types can be used as a decision support tool for sustainable landscape management strategy and local management practices in forested cultural lowland landscapes. Improvements in both regional and local ecological knowledge are generally needed in order to control floodplain land use decisions, which are typically made on the scale of landscape management

Urban Forest Recreation and Its Possible Role throughout the COVID-19 Pandemic

Urban forests provide benefits in terms of the environment and society. Many people living in urban areas could profit from the recreational services provided by urban forests to alleviate the physical and psychological stresses caused by closure restrictions during the COVID-19 epidemic. However, limited research has been conducted on the role of forest recreation during the COVID-19 lockdown to support future policy decisions regarding such dramatic circumstances. The study aims to investigate the frequency of visitors in the reference Training Forest Enterprise Masaryk Forest Křtiny in Brno, Czech Republic, and to verify if the lockdown led to its intensified use, under the context of weather conditions. Data were collected using a Pyro Box Compact reader and TRAFx Infrared Trail Counter. Regression analysis was performed to determine whether individual weather factors significantly influenced the intensity of forest visitations before and during COVID-19. The number of visits in 2021 during the strict lockdown and post-lockdown periods was significantly higher during spring and autumn than in 2016 and 2017, respectively. The frequency pattern of forest users visibly changed in 2021, and the total number of visits was much higher, even though 2021 had worse weather than the reference years before the pandemic. The results show the recreational use and importance of the forest, especially during the pandemic. This work is a continuation of our previous research with regard to this area, which indicated the importance of forest recreational services for the well-being and health of city dwellers

Cross-modal associations of human body odour attractiveness with facial and vocal attractiveness provide little support for the backup signals hypothesis: A systematic review and meta-analysis

Potential mating partners are typically assessed for their attractiveness by integrating multiple sensory modalities, including olfactory, visual, and auditory cues. There have been diverging predictions on how the individual modalities should relate to each other. According to the backup signals hypothesis, the assessment of multimodal cues provides redundant information, whereas the multiple messages hypothesis suggests that different modalities provide independent and non-redundant information about an individual’s mating-related quality. The backup signals hypothesis predicts a positive association between assessments of different modalities, whereas no substantial correlation across modalities is expected under the ‘multiple messages‘ hypothesis. Previous studies testing the two hypotheses have provided mixed results, but a systematic evaluation is currently missing. We performed a systematic review and a meta-analysis of published and unpublished studies to examine the congruence in assessments between body odour and facial attractiveness, and body odour and vocal attractiveness, in humans. We found positive but weak associations between attractiveness ratings of body odours and faces ( r = 0.1, k = 25), and between body odours and voices ( r = 0.1, k = 9). No sex differences were observed in the magnitudes of effects. Our results suggest that assessments of human body odour and facial and vocal attractiveness may provide independent and non-redundant information about mating-related qualities. The findings of the resent study provide little support for the backup signals hypothesis and may be better explained by the multiple messages hypothesis.Output Status: Forthcoming/Available Onlin