Evidence for the stress-linked immunocompetence handicap hypothesis in humans

Secondary sexual traits that develop under the action of testosterone, such as masculine human male facial characteristics, have been proposed to signal the strength of the immune system due to the sex hormone's immunosuppressive action. Recent work has suggested that glucocorticoid stress hormones may also influence expression of such sexual signals due to their effects on immune function. Precise roles, however, remain unclear. Here we show positive relationships between testosterone, facial attractiveness and immune function (antibody response to a hepatitis B vaccine) in human males, and present some preliminary evidence that these relationships are moderated by naturally co-occurring cortisol (a glucocorticoid stress hormone involved in the fight-or-flight response). We conclude that our results provide support for a role of glucocorticoids in hormonally mediated sexual selection

The contribution of dormice monitoring to the assessment of the conservation status of species in Latvia in accordance with IUCN criteria

In Latvia, four dormouse species have been recorded. In 2016 an annual monitoring of the Hazel Dormouse (Muscardinus avellanarius) and Forest Dormouse (Dryomys nitedula) was commenced within the national biodiversity monitoring programme to obtain data that would allow assessmen of the conservation status of those species and their habitats.The nestbox method was used for the surveys, as it is equally suitable for collecting data on all four species of dormice. Since 2016, 133 temporary study plots with 5–15 nest-boxes each, were established all over the country to record species presence. Sevenadditional permanent study plots collected data on population dynamics, each consisting of at least 50 nestboxes placed within a grid system at 50 m intervals.No Garden Dormice (Eliomys quercinus) were recorded, supporting the presumption that this species has vanished in Latvia. A new location for Edible Dormouse (Glis glis) has been discovered. The Forest Dormouse is found exclusively in a small area near the Latvia-Belarus border, but Hazel Dormice found in Latvia are probably are part of a metapopulation located to the south. No overlapping of distribution areas of species was found.The previous assessment of dormouse species, according to outdated IUCN criteria, was done 20 years ago. Re-assessment according to current IUCN criteria, and using monitoring data, is now carried out within the recently commenced LIFE FOR SPECIES project (2021–2024). Preliminary assessments indicate that each dormouse species will be classified in different categories - rangingfrom Least Concern to Regionally Extinct.

Data from: Senescence in immune priming and attractiveness in a beetle

Age-related decline in immune activity is referred to as immunosenescence and has been observed for both the adaptive immune response of vertebrates and the innate immune system of invertebrates. Since maintaining a basic level of immune defence and mounting an immune response is costly, optimal investment in immune function should vary over a wide range of individual states such as the individual’s age. In this study we tested whether the immune response and immunological priming within individuals become less efficient with age using mealworm beetles, Tenebrio molitor, as a model organism. We also tested whether aging and immunological priming affected the odours produced by males. We found that young males of T.molitor were capable of mounting an immune response a sterile nylon monofilament implant with the potential to exhibit a simple form of immune memory through mechanisms of immune priming. Older males did not increase their immune response to a second immune challenge, which negatively affected their sexual attractiveness and remaining life span. Our results indicate that the immune system of older males in T.molitor is less effective, suggesting complex evolutionary trade-offs between ageing, immune response and sexual attractiveness

The potential antifeedant activity of lichen-forming fungal extracts against the invasive Spanish slug (Arion vulgaris)

The protection of horticultural crops from slug feeding can be achieved using slug pellets; however, application of molluscicides is not always safe to the environment. There is a need for alternative methods to reduce the palatability of crop plants. Chemical properties of secondary compounds from lichens influence the feeding behaviour of slugs. Liquid extracts of three lichen species, Cladonia rangiferina (L.) F.H. Wigg., Cladonia stellaris (Opiz) Pouzar Vězda and Pseudevernia furfuracea (L.) Zopf, were applied to three different crops and tested for their antifeedant properties against an important agricultural pest, the Spanish slug Arion vulgaris (Moquin-Tandon, 1855). All three extracts had specific activity, showing a decrease in grazing intensity and also slug weight loss after feeding on treated food. Slugs significantly gained weight after feeding under control condition; however, they did not gain weight when fed on extract-treated food. The most effective extract was from P. furfuracea. We propose to use properties of lichen extracts to develop new environmentally friendly molluscicides.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Senescence of immunity in Tenebrio molitor - J Evol Biol

This excel file contains the data on encapsulation response of young and old males and their attractiveness. The attractiveness was measured as the total time females spent (s) and number of visits of females on pheromone discs of the males

Data from: Adiposity, compared with masculinity, serves as a more valid cue to immunocompetence in human mate choice

According to the “good genes” hypothesis, females choose males based on traits that indicate the male’s genetic quality in terms of disease resistance. The “immunocompetence handicap hypothesis (ICHH)” proposed that secondary sexual traits serve as indicators of male genetic quality because they indicate that males can contend with the immunosuppressive effects of testosterone. Masculinity is commonly assumed to serve as such a secondary sexual trait. Yet women do not consistently prefer masculine looking men, nor is masculinity consistently related to health across studies. Here we show that adiposity, but not masculinity, significantly mediates the relationship between a direct measure of immune response (Hepatitis B antibody response) and attractiveness for both body and facial measurements. In addition, we show that circulating testosterone is more closely associated with adiposity than masculinity. These findings indicate that adiposity, compared to masculinity, serves as a more important cue to immunocompetence in female mate choice

Data from: Facial attractiveness is related to women’s cortisol and body fat, but not with immune responsiveness

Recent studies suggest that facial attractiveness indicates immune responsiveness in men and that this relationship is moderated by stress hormones which interact with testosterone levels. However, studies testing whether facial attractiveness in women signals their immune responsiveness are lacking. Here, we photographed young Latvian women, vaccinated them against hepatitis B and measured the amount of specific antibodies produced, cortisol levels and percentage body fat. Latvian men rated the attractiveness of the women's faces. Interestingly, in women, immune responsiveness (amount of antibodies produced) did not predict facial attractiveness. Instead, plasma cortisol level was negatively associated with attractiveness, indicating that stressed women look less attractive. Fat percentage was curvilinearly associated with facial attractiveness, indicating that being too thin or too fat reduces attractiveness. Our study suggests that in contrast to men, facial attractiveness in women does not indicate immune responsiveness against hepatitis B, but is associated with two other aspects of long-term health and fertility: circulating levels of the stress hormone cortisol and percentage body fat